sharpetronics/PostgreSQL
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-17 00:06:40 -04:00
Code Issues Projects Releases Wiki Activity
PostgreSQL/src/backend/optimizer/plan/planner.c
Robert Haas 9da0cc3528 Support parallel btree index builds. 
To make this work, tuplesort.c and logtape.c must also support
parallelism, so this patch adds that infrastructure and then applies
it to the particular case of parallel btree index builds.  Testing
to date shows that this can often be 2-3x faster than a serial
index build.

The model for deciding how many workers to use is fairly primitive
at present, but it's better than not having the feature.  We can
refine it as we get more experience.

Peter Geoghegan with some help from Rushabh Lathia.  While Heikki
Linnakangas is not an author of this patch, he wrote other patches
without which this feature would not have been possible, and
therefore the release notes should possibly credit him as an author
of this feature.  Reviewed by Claudio Freire, Heikki Linnakangas,
Thomas Munro, Tels, Amit Kapila, me.

Discussion: http://postgr.es/m/CAM3SWZQKM=Pzc=CAHzRixKjp2eO5Q0Jg1SoFQqeXFQ647JiwqQ@mail.gmail.com
Discussion: http://postgr.es/m/CAH2-Wz=AxWqDoVvGU7dq856S4r6sJAj6DBn7VMtigkB33N5eyg@mail.gmail.com
2018-02-02 13:32:44 -05:00

6437 lines
201 KiB
C
Raw Blame History

/*-------------------------------------------------------------------------
*
* planner.c
* The query optimizer external interface.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/optimizer/plan/planner.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <limits.h>
#include <math.h>
#include "access/htup_details.h"
#include "access/parallel.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/pg_constraint_fn.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "executor/nodeAgg.h"
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "lib/bipartite_match.h"
#include "lib/knapsack.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#ifdef OPTIMIZER_DEBUG
#include "nodes/print.h"
#endif
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parsetree.h"
#include "parser/parse_agg.h"
#include "rewrite/rewriteManip.h"
#include "storage/dsm_impl.h"
#include "utils/rel.h"
#include "utils/selfuncs.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/* GUC parameters */
double cursor_tuple_fraction = DEFAULT_CURSOR_TUPLE_FRACTION;
int force_parallel_mode = FORCE_PARALLEL_OFF;
bool parallel_leader_participation = true;
/* Hook for plugins to get control in planner() */
planner_hook_type planner_hook = NULL;
/* Hook for plugins to get control when grouping_planner() plans upper rels */
create_upper_paths_hook_type create_upper_paths_hook = NULL;
/* Expression kind codes for preprocess_expression */
#define EXPRKIND_QUAL 0
#define EXPRKIND_TARGET 1
#define EXPRKIND_RTFUNC 2
#define EXPRKIND_RTFUNC_LATERAL 3
#define EXPRKIND_VALUES 4
#define EXPRKIND_VALUES_LATERAL 5
#define EXPRKIND_LIMIT 6
#define EXPRKIND_APPINFO 7
#define EXPRKIND_PHV 8
#define EXPRKIND_TABLESAMPLE 9
#define EXPRKIND_ARBITER_ELEM 10
#define EXPRKIND_TABLEFUNC 11
#define EXPRKIND_TABLEFUNC_LATERAL 12
/* Passthrough data for standard_qp_callback */
typedef struct
{
List *tlist; /* preprocessed query targetlist */
List *activeWindows; /* active windows, if any */
List *groupClause; /* overrides parse->groupClause */
} standard_qp_extra;
/*
* Data specific to grouping sets
*/
typedef struct
{
List *rollups;
List *hash_sets_idx;
double dNumHashGroups;
bool any_hashable;
Bitmapset *unsortable_refs;
Bitmapset *unhashable_refs;
List *unsortable_sets;
int *tleref_to_colnum_map;
} grouping_sets_data;
/* Local functions */
static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind);
static void preprocess_qual_conditions(PlannerInfo *root, Node *jtnode);
static void inheritance_planner(PlannerInfo *root);
static void grouping_planner(PlannerInfo *root, bool inheritance_update,
double tuple_fraction);
static grouping_sets_data *preprocess_grouping_sets(PlannerInfo *root);
static List *remap_to_groupclause_idx(List *groupClause, List *gsets,
int *tleref_to_colnum_map);
static void preprocess_rowmarks(PlannerInfo *root);
static double preprocess_limit(PlannerInfo *root,
double tuple_fraction,
int64 *offset_est, int64 *count_est);
static bool limit_needed(Query *parse);
static void remove_useless_groupby_columns(PlannerInfo *root);
static List *preprocess_groupclause(PlannerInfo *root, List *force);
static List *extract_rollup_sets(List *groupingSets);
static List *reorder_grouping_sets(List *groupingSets, List *sortclause);
static void standard_qp_callback(PlannerInfo *root, void *extra);
static double get_number_of_groups(PlannerInfo *root,
double path_rows,
grouping_sets_data *gd);
static Size estimate_hashagg_tablesize(Path *path,
const AggClauseCosts *agg_costs,
double dNumGroups);
static RelOptInfo *create_grouping_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *target,
const AggClauseCosts *agg_costs,
grouping_sets_data *gd);
static void consider_groupingsets_paths(PlannerInfo *root,
RelOptInfo *grouped_rel,
Path *path,
bool is_sorted,
bool can_hash,
PathTarget *target,
grouping_sets_data *gd,
const AggClauseCosts *agg_costs,
double dNumGroups);
static RelOptInfo *create_window_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *input_target,
PathTarget *output_target,
List *tlist,
WindowFuncLists *wflists,
List *activeWindows);
static void create_one_window_path(PlannerInfo *root,
RelOptInfo *window_rel,
Path *path,
PathTarget *input_target,
PathTarget *output_target,
List *tlist,
WindowFuncLists *wflists,
List *activeWindows);
static RelOptInfo *create_distinct_paths(PlannerInfo *root,
RelOptInfo *input_rel);
static RelOptInfo *create_ordered_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *target,
double limit_tuples);
static PathTarget *make_group_input_target(PlannerInfo *root,
PathTarget *final_target);
static PathTarget *make_partial_grouping_target(PlannerInfo *root,
PathTarget *grouping_target);
static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist);
static List *select_active_windows(PlannerInfo *root, WindowFuncLists *wflists);
static PathTarget *make_window_input_target(PlannerInfo *root,
PathTarget *final_target,
List *activeWindows);
static List *make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
List *tlist);
static PathTarget *make_sort_input_target(PlannerInfo *root,
PathTarget *final_target,
bool *have_postponed_srfs);
static void adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel,
List *targets, List *targets_contain_srfs);
static void add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *grouped_rel, PathTarget *target,
PathTarget *partial_grouping_target,
const AggClauseCosts *agg_costs,
const AggClauseCosts *agg_final_costs,
grouping_sets_data *gd, bool can_sort, bool can_hash,
double dNumGroups, List *havingQual);
static void add_partial_paths_to_grouping_rel(PlannerInfo *root,
RelOptInfo *input_rel,
RelOptInfo *grouped_rel,
PathTarget *target,
PathTarget *partial_grouping_target,
AggClauseCosts *agg_partial_costs,
AggClauseCosts *agg_final_costs,
grouping_sets_data *gd,
bool can_sort,
bool can_hash,
List *havingQual);
static bool can_parallel_agg(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *grouped_rel, const AggClauseCosts *agg_costs);
/*****************************************************************************
*
* Query optimizer entry point
*
* To support loadable plugins that monitor or modify planner behavior,
* we provide a hook variable that lets a plugin get control before and
* after the standard planning process. The plugin would normally call
* standard_planner().
*
* Note to plugin authors: standard_planner() scribbles on its Query input,
* so you'd better copy that data structure if you want to plan more than once.
*
*****************************************************************************/
PlannedStmt *
planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
{
PlannedStmt *result;
if (planner_hook)
result = (*planner_hook) (parse, cursorOptions, boundParams);
else
result = standard_planner(parse, cursorOptions, boundParams);
return result;
}
PlannedStmt *
standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
{
PlannedStmt *result;
PlannerGlobal *glob;
double tuple_fraction;
PlannerInfo *root;
RelOptInfo *final_rel;
Path *best_path;
Plan *top_plan;
ListCell *lp,
*lr;
/*
* Set up global state for this planner invocation. This data is needed
* across all levels of sub-Query that might exist in the given command,
* so we keep it in a separate struct that's linked to by each per-Query
* PlannerInfo.
*/
glob = makeNode(PlannerGlobal);
glob->boundParams = boundParams;
glob->subplans = NIL;
glob->subroots = NIL;
glob->rewindPlanIDs = NULL;
glob->finalrtable = NIL;
glob->finalrowmarks = NIL;
glob->resultRelations = NIL;
glob->nonleafResultRelations = NIL;
glob->rootResultRelations = NIL;
glob->relationOids = NIL;
glob->invalItems = NIL;
glob->paramExecTypes = NIL;
glob->lastPHId = 0;
glob->lastRowMarkId = 0;
glob->lastPlanNodeId = 0;
glob->transientPlan = false;
glob->dependsOnRole = false;
/*
* Assess whether it's feasible to use parallel mode for this query. We
* can't do this in a standalone backend, or if the command will try to
* modify any data, or if this is a cursor operation, or if GUCs are set
* to values that don't permit parallelism, or if parallel-unsafe
* functions are present in the query tree.
*
* (Note that we do allow CREATE TABLE AS, SELECT INTO, and CREATE
* MATERIALIZED VIEW to use parallel plans, but this is safe only because
* the command is writing into a completely new table which workers won't
* be able to see. If the workers could see the table, the fact that
* group locking would cause them to ignore the leader's heavyweight
* relation extension lock and GIN page locks would make this unsafe.
* We'll have to fix that somehow if we want to allow parallel inserts in
* general; updates and deletes have additional problems especially around
* combo CIDs.)
*
* For now, we don't try to use parallel mode if we're running inside a
* parallel worker. We might eventually be able to relax this
* restriction, but for now it seems best not to have parallel workers
* trying to create their own parallel workers.
*
* We can't use parallelism in serializable mode because the predicate
* locking code is not parallel-aware. It's not catastrophic if someone
* tries to run a parallel plan in serializable mode; it just won't get
* any workers and will run serially. But it seems like a good heuristic
* to assume that the same serialization level will be in effect at plan
* time and execution time, so don't generate a parallel plan if we're in
* serializable mode.
*/
if ((cursorOptions & CURSOR_OPT_PARALLEL_OK) != 0 &&
IsUnderPostmaster &&
dynamic_shared_memory_type != DSM_IMPL_NONE &&
parse->commandType == CMD_SELECT &&
!parse->hasModifyingCTE &&
max_parallel_workers_per_gather > 0 &&
!IsParallelWorker() &&
!IsolationIsSerializable())
{
/* all the cheap tests pass, so scan the query tree */
glob->maxParallelHazard = max_parallel_hazard(parse);
glob->parallelModeOK = (glob->maxParallelHazard != PROPARALLEL_UNSAFE);
}
else
{
/* skip the query tree scan, just assume it's unsafe */
glob->maxParallelHazard = PROPARALLEL_UNSAFE;
glob->parallelModeOK = false;
}
/*
* glob->parallelModeNeeded is normally set to false here and changed to
* true during plan creation if a Gather or Gather Merge plan is actually
* created (cf. create_gather_plan, create_gather_merge_plan).
*
* However, if force_parallel_mode = on or force_parallel_mode = regress,
* then we impose parallel mode whenever it's safe to do so, even if the
* final plan doesn't use parallelism. It's not safe to do so if the
* query contains anything parallel-unsafe; parallelModeOK will be false
* in that case. Note that parallelModeOK can't change after this point.
* Otherwise, everything in the query is either parallel-safe or
* parallel-restricted, and in either case it should be OK to impose
* parallel-mode restrictions. If that ends up breaking something, then
* either some function the user included in the query is incorrectly
* labelled as parallel-safe or parallel-restricted when in reality it's
* parallel-unsafe, or else the query planner itself has a bug.
*/
glob->parallelModeNeeded = glob->parallelModeOK &&
(force_parallel_mode != FORCE_PARALLEL_OFF);
/* Determine what fraction of the plan is likely to be scanned */
if (cursorOptions & CURSOR_OPT_FAST_PLAN)
{
/*
* We have no real idea how many tuples the user will ultimately FETCH
* from a cursor, but it is often the case that he doesn't want 'em
* all, or would prefer a fast-start plan anyway so that he can
* process some of the tuples sooner. Use a GUC parameter to decide
* what fraction to optimize for.
*/
tuple_fraction = cursor_tuple_fraction;
/*
* We document cursor_tuple_fraction as simply being a fraction, which
* means the edge cases 0 and 1 have to be treated specially here. We
* convert 1 to 0 ("all the tuples") and 0 to a very small fraction.
*/
if (tuple_fraction >= 1.0)
tuple_fraction = 0.0;
else if (tuple_fraction <= 0.0)
tuple_fraction = 1e-10;
}
else
{
/* Default assumption is we need all the tuples */
tuple_fraction = 0.0;
}
/* primary planning entry point (may recurse for subqueries) */
root = subquery_planner(glob, parse, NULL,
false, tuple_fraction);
/* Select best Path and turn it into a Plan */
final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
top_plan = create_plan(root, best_path);
/*
* If creating a plan for a scrollable cursor, make sure it can run
* backwards on demand. Add a Material node at the top at need.
*/
if (cursorOptions & CURSOR_OPT_SCROLL)
{
if (!ExecSupportsBackwardScan(top_plan))
top_plan = materialize_finished_plan(top_plan);
}
/*
* Optionally add a Gather node for testing purposes, provided this is
* actually a safe thing to do.
*/
if (force_parallel_mode != FORCE_PARALLEL_OFF && top_plan->parallel_safe)
{
Gather *gather = makeNode(Gather);
/*
* If there are any initPlans attached to the formerly-top plan node,
* move them up to the Gather node; same as we do for Material node in
* materialize_finished_plan.
*/
gather->plan.initPlan = top_plan->initPlan;
top_plan->initPlan = NIL;
gather->plan.targetlist = top_plan->targetlist;
gather->plan.qual = NIL;
gather->plan.lefttree = top_plan;
gather->plan.righttree = NULL;
gather->num_workers = 1;
gather->single_copy = true;
gather->invisible = (force_parallel_mode == FORCE_PARALLEL_REGRESS);
/*
* Since this Gather has no parallel-aware descendants to signal to,
* we don't need a rescan Param.
*/
gather->rescan_param = -1;
/*
* Ideally we'd use cost_gather here, but setting up dummy path data
* to satisfy it doesn't seem much cleaner than knowing what it does.
*/
gather->plan.startup_cost = top_plan->startup_cost +
parallel_setup_cost;
gather->plan.total_cost = top_plan->total_cost +
parallel_setup_cost + parallel_tuple_cost * top_plan->plan_rows;
gather->plan.plan_rows = top_plan->plan_rows;
gather->plan.plan_width = top_plan->plan_width;
gather->plan.parallel_aware = false;
gather->plan.parallel_safe = false;
/* use parallel mode for parallel plans. */
root->glob->parallelModeNeeded = true;
top_plan = &gather->plan;
}
/*
* If any Params were generated, run through the plan tree and compute
* each plan node's extParam/allParam sets. Ideally we'd merge this into
* set_plan_references' tree traversal, but for now it has to be separate
* because we need to visit subplans before not after main plan.
*/
if (glob->paramExecTypes != NIL)
{
Assert(list_length(glob->subplans) == list_length(glob->subroots));
forboth(lp, glob->subplans, lr, glob->subroots)
{
Plan *subplan = (Plan *) lfirst(lp);
PlannerInfo *subroot = lfirst_node(PlannerInfo, lr);
SS_finalize_plan(subroot, subplan);
}
SS_finalize_plan(root, top_plan);
}
/* final cleanup of the plan */
Assert(glob->finalrtable == NIL);
Assert(glob->finalrowmarks == NIL);
Assert(glob->resultRelations == NIL);
Assert(glob->nonleafResultRelations == NIL);
Assert(glob->rootResultRelations == NIL);
top_plan = set_plan_references(root, top_plan);
/* ... and the subplans (both regular subplans and initplans) */
Assert(list_length(glob->subplans) == list_length(glob->subroots));
forboth(lp, glob->subplans, lr, glob->subroots)
{
Plan *subplan = (Plan *) lfirst(lp);
PlannerInfo *subroot = lfirst_node(PlannerInfo, lr);
lfirst(lp) = set_plan_references(subroot, subplan);
}
/* build the PlannedStmt result */
result = makeNode(PlannedStmt);
result->commandType = parse->commandType;
result->queryId = parse->queryId;
result->hasReturning = (parse->returningList != NIL);
result->hasModifyingCTE = parse->hasModifyingCTE;
result->canSetTag = parse->canSetTag;
result->transientPlan = glob->transientPlan;
result->dependsOnRole = glob->dependsOnRole;
result->parallelModeNeeded = glob->parallelModeNeeded;
result->planTree = top_plan;
result->rtable = glob->finalrtable;
result->resultRelations = glob->resultRelations;
result->nonleafResultRelations = glob->nonleafResultRelations;
result->rootResultRelations = glob->rootResultRelations;
result->subplans = glob->subplans;
result->rewindPlanIDs = glob->rewindPlanIDs;
result->rowMarks = glob->finalrowmarks;
result->relationOids = glob->relationOids;
result->invalItems = glob->invalItems;
result->paramExecTypes = glob->paramExecTypes;
/* utilityStmt should be null, but we might as well copy it */
result->utilityStmt = parse->utilityStmt;
result->stmt_location = parse->stmt_location;
result->stmt_len = parse->stmt_len;
return result;
}
/*--------------------
* subquery_planner
* Invokes the planner on a subquery. We recurse to here for each
* sub-SELECT found in the query tree.
*
* glob is the global state for the current planner run.
* parse is the querytree produced by the parser & rewriter.
* parent_root is the immediate parent Query's info (NULL at the top level).
* hasRecursion is true if this is a recursive WITH query.
* tuple_fraction is the fraction of tuples we expect will be retrieved.
* tuple_fraction is interpreted as explained for grouping_planner, below.
*
* Basically, this routine does the stuff that should only be done once
* per Query object. It then calls grouping_planner. At one time,
* grouping_planner could be invoked recursively on the same Query object;
* that's not currently true, but we keep the separation between the two
* routines anyway, in case we need it again someday.
*
* subquery_planner will be called recursively to handle sub-Query nodes
* found within the query's expressions and rangetable.
*
* Returns the PlannerInfo struct ("root") that contains all data generated
* while planning the subquery. In particular, the Path(s) attached to
* the (UPPERREL_FINAL, NULL) upperrel represent our conclusions about the
* cheapest way(s) to implement the query. The top level will select the
* best Path and pass it through createplan.c to produce a finished Plan.
*--------------------
*/
PlannerInfo *
subquery_planner(PlannerGlobal *glob, Query *parse,
PlannerInfo *parent_root,
bool hasRecursion, double tuple_fraction)
{
PlannerInfo *root;
List *newWithCheckOptions;
List *newHaving;
bool hasOuterJoins;
RelOptInfo *final_rel;
ListCell *l;
/* Create a PlannerInfo data structure for this subquery */
root = makeNode(PlannerInfo);
root->parse = parse;
root->glob = glob;
root->query_level = parent_root ? parent_root->query_level + 1 : 1;
root->parent_root = parent_root;
root->plan_params = NIL;
root->outer_params = NULL;
root->planner_cxt = CurrentMemoryContext;
root->init_plans = NIL;
root->cte_plan_ids = NIL;
root->multiexpr_params = NIL;
root->eq_classes = NIL;
root->append_rel_list = NIL;
root->pcinfo_list = NIL;
root->rowMarks = NIL;
memset(root->upper_rels, 0, sizeof(root->upper_rels));
memset(root->upper_targets, 0, sizeof(root->upper_targets));
root->processed_tlist = NIL;
root->grouping_map = NULL;
root->minmax_aggs = NIL;
root->qual_security_level = 0;
root->hasInheritedTarget = false;
root->hasRecursion = hasRecursion;
if (hasRecursion)
root->wt_param_id = SS_assign_special_param(root);
else
root->wt_param_id = -1;
root->non_recursive_path = NULL;
/*
* If there is a WITH list, process each WITH query and build an initplan
* SubPlan structure for it.
*/
if (parse->cteList)
SS_process_ctes(root);
/*
* Look for ANY and EXISTS SubLinks in WHERE and JOIN/ON clauses, and try
* to transform them into joins. Note that this step does not descend
* into subqueries; if we pull up any subqueries below, their SubLinks are
* processed just before pulling them up.
*/
if (parse->hasSubLinks)
pull_up_sublinks(root);
/*
* Scan the rangetable for set-returning functions, and inline them if
* possible (producing subqueries that might get pulled up next).
* Recursion issues here are handled in the same way as for SubLinks.
*/
inline_set_returning_functions(root);
/*
* Check to see if any subqueries in the jointree can be merged into this
* query.
*/
pull_up_subqueries(root);
/*
* If this is a simple UNION ALL query, flatten it into an appendrel. We
* do this now because it requires applying pull_up_subqueries to the leaf
* queries of the UNION ALL, which weren't touched above because they
* weren't referenced by the jointree (they will be after we do this).
*/
if (parse->setOperations)
flatten_simple_union_all(root);
/*
* Detect whether any rangetable entries are RTE_JOIN kind; if not, we can
* avoid the expense of doing flatten_join_alias_vars(). Also check for
* outer joins --- if none, we can skip reduce_outer_joins(). And check
* for LATERAL RTEs, too. This must be done after we have done
* pull_up_subqueries(), of course.
*/
root->hasJoinRTEs = false;
root->hasLateralRTEs = false;
hasOuterJoins = false;
foreach(l, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
if (rte->rtekind == RTE_JOIN)
{
root->hasJoinRTEs = true;
if (IS_OUTER_JOIN(rte->jointype))
hasOuterJoins = true;
}
if (rte->lateral)
root->hasLateralRTEs = true;
}
/*
* Preprocess RowMark information. We need to do this after subquery
* pullup (so that all non-inherited RTEs are present) and before
* inheritance expansion (so that the info is available for
* expand_inherited_tables to examine and modify).
*/
preprocess_rowmarks(root);
/*
* Expand any rangetable entries that are inheritance sets into "append
* relations". This can add entries to the rangetable, but they must be
* plain base relations not joins, so it's OK (and marginally more
* efficient) to do it after checking for join RTEs. We must do it after
* pulling up subqueries, else we'd fail to handle inherited tables in
* subqueries.
*/
expand_inherited_tables(root);
/*
* Set hasHavingQual to remember if HAVING clause is present. Needed
* because preprocess_expression will reduce a constant-true condition to
* an empty qual list ... but "HAVING TRUE" is not a semantic no-op.
*/
root->hasHavingQual = (parse->havingQual != NULL);
/* Clear this flag; might get set in distribute_qual_to_rels */
root->hasPseudoConstantQuals = false;
/*
* Do expression preprocessing on targetlist and quals, as well as other
* random expressions in the querytree. Note that we do not need to
* handle sort/group expressions explicitly, because they are actually
* part of the targetlist.
*/
parse->targetList = (List *)
preprocess_expression(root, (Node *) parse->targetList,
EXPRKIND_TARGET);
/* Constant-folding might have removed all set-returning functions */
if (parse->hasTargetSRFs)
parse->hasTargetSRFs = expression_returns_set((Node *) parse->targetList);
newWithCheckOptions = NIL;
foreach(l, parse->withCheckOptions)
{
WithCheckOption *wco = lfirst_node(WithCheckOption, l);
wco->qual = preprocess_expression(root, wco->qual,
EXPRKIND_QUAL);
if (wco->qual != NULL)
newWithCheckOptions = lappend(newWithCheckOptions, wco);
}
parse->withCheckOptions = newWithCheckOptions;
parse->returningList = (List *)
preprocess_expression(root, (Node *) parse->returningList,
EXPRKIND_TARGET);
preprocess_qual_conditions(root, (Node *) parse->jointree);
parse->havingQual = preprocess_expression(root, parse->havingQual,
EXPRKIND_QUAL);
foreach(l, parse->windowClause)
{
WindowClause *wc = lfirst_node(WindowClause, l);
/* partitionClause/orderClause are sort/group expressions */
wc->startOffset = preprocess_expression(root, wc->startOffset,
EXPRKIND_LIMIT);
wc->endOffset = preprocess_expression(root, wc->endOffset,
EXPRKIND_LIMIT);
}
parse->limitOffset = preprocess_expression(root, parse->limitOffset,
EXPRKIND_LIMIT);
parse->limitCount = preprocess_expression(root, parse->limitCount,
EXPRKIND_LIMIT);
if (parse->onConflict)
{
parse->onConflict->arbiterElems = (List *)
preprocess_expression(root,
(Node *) parse->onConflict->arbiterElems,
EXPRKIND_ARBITER_ELEM);
parse->onConflict->arbiterWhere =
preprocess_expression(root,
parse->onConflict->arbiterWhere,
EXPRKIND_QUAL);
parse->onConflict->onConflictSet = (List *)
preprocess_expression(root,
(Node *) parse->onConflict->onConflictSet,
EXPRKIND_TARGET);
parse->onConflict->onConflictWhere =
preprocess_expression(root,
parse->onConflict->onConflictWhere,
EXPRKIND_QUAL);
/* exclRelTlist contains only Vars, so no preprocessing needed */
}
root->append_rel_list = (List *)
preprocess_expression(root, (Node *) root->append_rel_list,
EXPRKIND_APPINFO);
/* Also need to preprocess expressions within RTEs */
foreach(l, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
int kind;
ListCell *lcsq;
if (rte->rtekind == RTE_RELATION)
{
if (rte->tablesample)
rte->tablesample = (TableSampleClause *)
preprocess_expression(root,
(Node *) rte->tablesample,
EXPRKIND_TABLESAMPLE);
}
else if (rte->rtekind == RTE_SUBQUERY)
{
/*
* We don't want to do all preprocessing yet on the subquery's
* expressions, since that will happen when we plan it. But if it
* contains any join aliases of our level, those have to get
* expanded now, because planning of the subquery won't do it.
* That's only possible if the subquery is LATERAL.
*/
if (rte->lateral && root->hasJoinRTEs)
rte->subquery = (Query *)
flatten_join_alias_vars(root, (Node *) rte->subquery);
}
else if (rte->rtekind == RTE_FUNCTION)
{
/* Preprocess the function expression(s) fully */
kind = rte->lateral ? EXPRKIND_RTFUNC_LATERAL : EXPRKIND_RTFUNC;
rte->functions = (List *)
preprocess_expression(root, (Node *) rte->functions, kind);
}
else if (rte->rtekind == RTE_TABLEFUNC)
{
/* Preprocess the function expression(s) fully */
kind = rte->lateral ? EXPRKIND_TABLEFUNC_LATERAL : EXPRKIND_TABLEFUNC;
rte->tablefunc = (TableFunc *)
preprocess_expression(root, (Node *) rte->tablefunc, kind);
}
else if (rte->rtekind == RTE_VALUES)
{
/* Preprocess the values lists fully */
kind = rte->lateral ? EXPRKIND_VALUES_LATERAL : EXPRKIND_VALUES;
rte->values_lists = (List *)
preprocess_expression(root, (Node *) rte->values_lists, kind);
}
/*
* Process each element of the securityQuals list as if it were a
* separate qual expression (as indeed it is). We need to do it this
* way to get proper canonicalization of AND/OR structure. Note that
* this converts each element into an implicit-AND sublist.
*/
foreach(lcsq, rte->securityQuals)
{
lfirst(lcsq) = preprocess_expression(root,
(Node *) lfirst(lcsq),
EXPRKIND_QUAL);
}
}
/*
* Now that we are done preprocessing expressions, and in particular done
* flattening join alias variables, get rid of the joinaliasvars lists.
* They no longer match what expressions in the rest of the tree look
* like, because we have not preprocessed expressions in those lists (and
* do not want to; for example, expanding a SubLink there would result in
* a useless unreferenced subplan). Leaving them in place simply creates
* a hazard for later scans of the tree. We could try to prevent that by
* using QTW_IGNORE_JOINALIASES in every tree scan done after this point,
* but that doesn't sound very reliable.
*/
if (root->hasJoinRTEs)
{
foreach(l, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
rte->joinaliasvars = NIL;
}
}
/*
* In some cases we may want to transfer a HAVING clause into WHERE. We
* cannot do so if the HAVING clause contains aggregates (obviously) or
* volatile functions (since a HAVING clause is supposed to be executed
* only once per group). We also can't do this if there are any nonempty
* grouping sets; moving such a clause into WHERE would potentially change
* the results, if any referenced column isn't present in all the grouping
* sets. (If there are only empty grouping sets, then the HAVING clause
* must be degenerate as discussed below.)
*
* Also, it may be that the clause is so expensive to execute that we're
* better off doing it only once per group, despite the loss of
* selectivity. This is hard to estimate short of doing the entire
* planning process twice, so we use a heuristic: clauses containing
* subplans are left in HAVING. Otherwise, we move or copy the HAVING
* clause into WHERE, in hopes of eliminating tuples before aggregation
* instead of after.
*
* If the query has explicit grouping then we can simply move such a
* clause into WHERE; any group that fails the clause will not be in the
* output because none of its tuples will reach the grouping or
* aggregation stage. Otherwise we must have a degenerate (variable-free)
* HAVING clause, which we put in WHERE so that query_planner() can use it
* in a gating Result node, but also keep in HAVING to ensure that we
* don't emit a bogus aggregated row. (This could be done better, but it
* seems not worth optimizing.)
*
* Note that both havingQual and parse->jointree->quals are in
* implicitly-ANDed-list form at this point, even though they are declared
* as Node *.
*/
newHaving = NIL;
foreach(l, (List *) parse->havingQual)
{
Node *havingclause = (Node *) lfirst(l);
if ((parse->groupClause && parse->groupingSets) ||
contain_agg_clause(havingclause) ||
contain_volatile_functions(havingclause) ||
contain_subplans(havingclause))
{
/* keep it in HAVING */
newHaving = lappend(newHaving, havingclause);
}
else if (parse->groupClause && !parse->groupingSets)
{
/* move it to WHERE */
parse->jointree->quals = (Node *)
lappend((List *) parse->jointree->quals, havingclause);
}
else
{
/* put a copy in WHERE, keep it in HAVING */
parse->jointree->quals = (Node *)
lappend((List *) parse->jointree->quals,
copyObject(havingclause));
newHaving = lappend(newHaving, havingclause);
}
}
parse->havingQual = (Node *) newHaving;
/* Remove any redundant GROUP BY columns */
remove_useless_groupby_columns(root);
/*
* If we have any outer joins, try to reduce them to plain inner joins.
* This step is most easily done after we've done expression
* preprocessing.
*/
if (hasOuterJoins)
reduce_outer_joins(root);
/*
* Do the main planning. If we have an inherited target relation, that
* needs special processing, else go straight to grouping_planner.
*/
if (parse->resultRelation &&
rt_fetch(parse->resultRelation, parse->rtable)->inh)
inheritance_planner(root);
else
grouping_planner(root, false, tuple_fraction);
/*
* Capture the set of outer-level param IDs we have access to, for use in
* extParam/allParam calculations later.
*/
SS_identify_outer_params(root);
/*
* If any initPlans were created in this query level, adjust the surviving
* Paths' costs and parallel-safety flags to account for them. The
* initPlans won't actually get attached to the plan tree till
* create_plan() runs, but we must include their effects now.
*/
final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
SS_charge_for_initplans(root, final_rel);
/*
* Make sure we've identified the cheapest Path for the final rel. (By
* doing this here not in grouping_planner, we include initPlan costs in
* the decision, though it's unlikely that will change anything.)
*/
set_cheapest(final_rel);
return root;
}
/*
* preprocess_expression
* Do subquery_planner's preprocessing work for an expression,
* which can be a targetlist, a WHERE clause (including JOIN/ON
* conditions), a HAVING clause, or a few other things.
*/
static Node *
preprocess_expression(PlannerInfo *root, Node *expr, int kind)
{
/*
* Fall out quickly if expression is empty. This occurs often enough to
* be worth checking. Note that null->null is the correct conversion for
* implicit-AND result format, too.
*/
if (expr == NULL)
return NULL;
/*
* If the query has any join RTEs, replace join alias variables with
* base-relation variables. We must do this first, since any expressions
* we may extract from the joinaliasvars lists have not been preprocessed.
* For example, if we did this after sublink processing, sublinks expanded
* out from join aliases would not get processed. But we can skip this in
* non-lateral RTE functions, VALUES lists, and TABLESAMPLE clauses, since
* they can't contain any Vars of the current query level.
*/
if (root->hasJoinRTEs &&
!(kind == EXPRKIND_RTFUNC ||
kind == EXPRKIND_VALUES ||
kind == EXPRKIND_TABLESAMPLE ||
kind == EXPRKIND_TABLEFUNC))
expr = flatten_join_alias_vars(root, expr);
/*
* Simplify constant expressions.
*
* Note: an essential effect of this is to convert named-argument function
* calls to positional notation and insert the current actual values of
* any default arguments for functions. To ensure that happens, we *must*
* process all expressions here. Previous PG versions sometimes skipped
* const-simplification if it didn't seem worth the trouble, but we can't
* do that anymore.
*
* Note: this also flattens nested AND and OR expressions into N-argument
* form. All processing of a qual expression after this point must be
* careful to maintain AND/OR flatness --- that is, do not generate a tree
* with AND directly under AND, nor OR directly under OR.
*/
expr = eval_const_expressions(root, expr);
/*
* If it's a qual or havingQual, canonicalize it.
*/
if (kind == EXPRKIND_QUAL)
{
expr = (Node *) canonicalize_qual((Expr *) expr);
#ifdef OPTIMIZER_DEBUG
printf("After canonicalize_qual()\n");
pprint(expr);
#endif
}
/* Expand SubLinks to SubPlans */
if (root->parse->hasSubLinks)
expr = SS_process_sublinks(root, expr, (kind == EXPRKIND_QUAL));
/*
* XXX do not insert anything here unless you have grokked the comments in
* SS_replace_correlation_vars ...
*/
/* Replace uplevel vars with Param nodes (this IS possible in VALUES) */
if (root->query_level > 1)
expr = SS_replace_correlation_vars(root, expr);
/*
* If it's a qual or havingQual, convert it to implicit-AND format. (We
* don't want to do this before eval_const_expressions, since the latter
* would be unable to simplify a top-level AND correctly. Also,
* SS_process_sublinks expects explicit-AND format.)
*/
if (kind == EXPRKIND_QUAL)
expr = (Node *) make_ands_implicit((Expr *) expr);
return expr;
}
/*
* preprocess_qual_conditions
* Recursively scan the query's jointree and do subquery_planner's
* preprocessing work on each qual condition found therein.
*/
static void
preprocess_qual_conditions(PlannerInfo *root, Node *jtnode)
{
if (jtnode == NULL)
return;
if (IsA(jtnode, RangeTblRef))
{
/* nothing to do here */
}
else if (IsA(jtnode, FromExpr))
{
FromExpr *f = (FromExpr *) jtnode;
ListCell *l;
foreach(l, f->fromlist)
preprocess_qual_conditions(root, lfirst(l));
f->quals = preprocess_expression(root, f->quals, EXPRKIND_QUAL);
}
else if (IsA(jtnode, JoinExpr))
{
JoinExpr *j = (JoinExpr *) jtnode;
preprocess_qual_conditions(root, j->larg);
preprocess_qual_conditions(root, j->rarg);
j->quals = preprocess_expression(root, j->quals, EXPRKIND_QUAL);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(jtnode));
}
/*
* preprocess_phv_expression
* Do preprocessing on a PlaceHolderVar expression that's been pulled up.
*
* If a LATERAL subquery references an output of another subquery, and that
* output must be wrapped in a PlaceHolderVar because of an intermediate outer
* join, then we'll push the PlaceHolderVar expression down into the subquery
* and later pull it back up during find_lateral_references, which runs after
* subquery_planner has preprocessed all the expressions that were in the
* current query level to start with. So we need to preprocess it then.
*/
Expr *
preprocess_phv_expression(PlannerInfo *root, Expr *expr)
{
return (Expr *) preprocess_expression(root, (Node *) expr, EXPRKIND_PHV);
}
/*
* inheritance_planner
* Generate Paths in the case where the result relation is an
* inheritance set.
*
* We have to handle this case differently from cases where a source relation
* is an inheritance set. Source inheritance is expanded at the bottom of the
* plan tree (see allpaths.c), but target inheritance has to be expanded at
* the top. The reason is that for UPDATE, each target relation needs a
* different targetlist matching its own column set. Fortunately,
* the UPDATE/DELETE target can never be the nullable side of an outer join,
* so it's OK to generate the plan this way.
*
* Returns nothing; the useful output is in the Paths we attach to
* the (UPPERREL_FINAL, NULL) upperrel stored in *root.
*
* Note that we have not done set_cheapest() on the final rel; it's convenient
* to leave this to the caller.
*/
static void
inheritance_planner(PlannerInfo *root)
{
Query *parse = root->parse;
int top_parentRTindex = parse->resultRelation;
Bitmapset *subqueryRTindexes;
Bitmapset *modifiableARIindexes;
int nominalRelation = -1;
List *final_rtable = NIL;
int save_rel_array_size = 0;
RelOptInfo **save_rel_array = NULL;
List *subpaths = NIL;
List *subroots = NIL;
List *resultRelations = NIL;
List *withCheckOptionLists = NIL;
List *returningLists = NIL;
List *rowMarks;
RelOptInfo *final_rel;
ListCell *lc;
Index rti;
RangeTblEntry *parent_rte;
List *partitioned_rels = NIL;
PlannerInfo *parent_root;
Query *parent_parse;
Bitmapset *parent_relids = bms_make_singleton(top_parentRTindex);
PlannerInfo **parent_roots = NULL;
bool partColsUpdated = false;
Assert(parse->commandType != CMD_INSERT);
/*
* We generate a modified instance of the original Query for each target
* relation, plan that, and put all the plans into a list that will be
* controlled by a single ModifyTable node. All the instances share the
* same rangetable, but each instance must have its own set of subquery
* RTEs within the finished rangetable because (1) they are likely to get
* scribbled on during planning, and (2) it's not inconceivable that
* subqueries could get planned differently in different cases. We need
* not create duplicate copies of other RTE kinds, in particular not the
* target relations, because they don't have either of those issues. Not
* having to duplicate the target relations is important because doing so
* (1) would result in a rangetable of length O(N^2) for N targets, with
* at least O(N^3) work expended here; and (2) would greatly complicate
* management of the rowMarks list.
*
* To begin with, generate a bitmapset of the relids of the subquery RTEs.
*/
subqueryRTindexes = NULL;
rti = 1;
foreach(lc, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
if (rte->rtekind == RTE_SUBQUERY)
subqueryRTindexes = bms_add_member(subqueryRTindexes, rti);
rti++;
}
/*
* Next, we want to identify which AppendRelInfo items contain references
* to any of the aforesaid subquery RTEs. These items will need to be
* copied and modified to adjust their subquery references; whereas the
* other ones need not be touched. It's worth being tense over this
* because we can usually avoid processing most of the AppendRelInfo
* items, thereby saving O(N^2) space and time when the target is a large
* inheritance tree. We can identify AppendRelInfo items by their
* child_relid, since that should be unique within the list.
*/
modifiableARIindexes = NULL;
if (subqueryRTindexes != NULL)
{
foreach(lc, root->append_rel_list)
{
AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
if (bms_is_member(appinfo->parent_relid, subqueryRTindexes) ||
bms_is_member(appinfo->child_relid, subqueryRTindexes) ||
bms_overlap(pull_varnos((Node *) appinfo->translated_vars),
subqueryRTindexes))
modifiableARIindexes = bms_add_member(modifiableARIindexes,
appinfo->child_relid);
}
}
/*
* If the parent RTE is a partitioned table, we should use that as the
* nominal relation, because the RTEs added for partitioned tables
* (including the root parent) as child members of the inheritance set do
* not appear anywhere else in the plan. The situation is exactly the
* opposite in the case of non-partitioned inheritance parent as described
* below. For the same reason, collect the list of descendant partitioned
* tables to be saved in ModifyTable node, so that executor can lock those
* as well.
*/
parent_rte = rt_fetch(top_parentRTindex, root->parse->rtable);
if (parent_rte->relkind == RELKIND_PARTITIONED_TABLE)
{
nominalRelation = top_parentRTindex;
partitioned_rels = get_partitioned_child_rels(root, top_parentRTindex,
&partColsUpdated);
/* The root partitioned table is included as a child rel */
Assert(list_length(partitioned_rels) >= 1);
}
/*
* The PlannerInfo for each child is obtained by translating the relevant
* members of the PlannerInfo for its immediate parent, which we find
* using the parent_relid in its AppendRelInfo. We save the PlannerInfo
* for each parent in an array indexed by relid for fast retrieval. Since
* the maximum number of parents is limited by the number of RTEs in the
* query, we use that number to allocate the array. An extra entry is
* needed since relids start from 1.
*/
parent_roots = (PlannerInfo **) palloc0((list_length(parse->rtable) + 1) *
sizeof(PlannerInfo *));
parent_roots[top_parentRTindex] = root;
/*
* And now we can get on with generating a plan for each child table.
*/
foreach(lc, root->append_rel_list)
{
AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
PlannerInfo *subroot;
RangeTblEntry *child_rte;
RelOptInfo *sub_final_rel;
Path *subpath;
/* append_rel_list contains all append rels; ignore others */
if (!bms_is_member(appinfo->parent_relid, parent_relids))
continue;
/*
* expand_inherited_rtentry() always processes a parent before any of
* that parent's children, so the parent_root for this relation should
* already be available.
*/
parent_root = parent_roots[appinfo->parent_relid];
Assert(parent_root != NULL);
parent_parse = parent_root->parse;
/*
* We need a working copy of the PlannerInfo so that we can control
* propagation of information back to the main copy.
*/
subroot = makeNode(PlannerInfo);
memcpy(subroot, parent_root, sizeof(PlannerInfo));
/*
* Generate modified query with this rel as target. We first apply
* adjust_appendrel_attrs, which copies the Query and changes
* references to the parent RTE to refer to the current child RTE,
* then fool around with subquery RTEs.
*/
subroot->parse = (Query *)
adjust_appendrel_attrs(parent_root,
(Node *) parent_parse,
1, &appinfo);
/*
* If there are securityQuals attached to the parent, move them to the
* child rel (they've already been transformed properly for that).
*/
parent_rte = rt_fetch(appinfo->parent_relid, subroot->parse->rtable);
child_rte = rt_fetch(appinfo->child_relid, subroot->parse->rtable);
child_rte->securityQuals = parent_rte->securityQuals;
parent_rte->securityQuals = NIL;
/*
* The rowMarks list might contain references to subquery RTEs, so
* make a copy that we can apply ChangeVarNodes to. (Fortunately, the
* executor doesn't need to see the modified copies --- we can just
* pass it the original rowMarks list.)
*/
subroot->rowMarks = copyObject(parent_root->rowMarks);
/*
* The append_rel_list likewise might contain references to subquery
* RTEs (if any subqueries were flattenable UNION ALLs). So prepare
* to apply ChangeVarNodes to that, too. As explained above, we only
* want to copy items that actually contain such references; the rest
* can just get linked into the subroot's append_rel_list.
*
* If we know there are no such references, we can just use the outer
* append_rel_list unmodified.
*/
if (modifiableARIindexes != NULL)
{
ListCell *lc2;
subroot->append_rel_list = NIL;
foreach(lc2, parent_root->append_rel_list)
{
AppendRelInfo *appinfo2 = lfirst_node(AppendRelInfo, lc2);
if (bms_is_member(appinfo2->child_relid, modifiableARIindexes))
appinfo2 = copyObject(appinfo2);
subroot->append_rel_list = lappend(subroot->append_rel_list,
appinfo2);
}
}
/*
* Add placeholders to the child Query's rangetable list to fill the
* RT indexes already reserved for subqueries in previous children.
* These won't be referenced, so there's no need to make them very
* valid-looking.
*/
while (list_length(subroot->parse->rtable) < list_length(final_rtable))
subroot->parse->rtable = lappend(subroot->parse->rtable,
makeNode(RangeTblEntry));
/*
* If this isn't the first child Query, generate duplicates of all
* subquery RTEs, and adjust Var numbering to reference the
* duplicates. To simplify the loop logic, we scan the original rtable
* not the copy just made by adjust_appendrel_attrs; that should be OK
* since subquery RTEs couldn't contain any references to the target
* rel.
*/
if (final_rtable != NIL && subqueryRTindexes != NULL)
{
ListCell *lr;
rti = 1;
foreach(lr, parent_parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lr);
if (bms_is_member(rti, subqueryRTindexes))
{
Index newrti;
/*
* The RTE can't contain any references to its own RT
* index, except in its securityQuals, so we can save a
* few cycles by applying ChangeVarNodes to the rest of
* the rangetable before we append the RTE to it.
*/
newrti = list_length(subroot->parse->rtable) + 1;
ChangeVarNodes((Node *) subroot->parse, rti, newrti, 0);
ChangeVarNodes((Node *) subroot->rowMarks, rti, newrti, 0);
/* Skip processing unchanging parts of append_rel_list */
if (modifiableARIindexes != NULL)
{
ListCell *lc2;
foreach(lc2, subroot->append_rel_list)
{
AppendRelInfo *appinfo2 = lfirst_node(AppendRelInfo, lc2);
if (bms_is_member(appinfo2->child_relid,
modifiableARIindexes))
ChangeVarNodes((Node *) appinfo2, rti, newrti, 0);
}
}
rte = copyObject(rte);
ChangeVarNodes((Node *) rte->securityQuals, rti, newrti, 0);
subroot->parse->rtable = lappend(subroot->parse->rtable,
rte);
}
rti++;
}
}
/* There shouldn't be any OJ info to translate, as yet */
Assert(subroot->join_info_list == NIL);
/* and we haven't created PlaceHolderInfos, either */
Assert(subroot->placeholder_list == NIL);
/* hack to mark target relation as an inheritance partition */
subroot->hasInheritedTarget = true;
/*
* If the child is further partitioned, remember it as a parent. Since
* a partitioned table does not have any data, we don't need to create
* a plan for it. We do, however, need to remember the PlannerInfo for
* use when processing its children.
*/
if (child_rte->inh)
{
Assert(child_rte->relkind == RELKIND_PARTITIONED_TABLE);
parent_relids =
bms_add_member(parent_relids, appinfo->child_relid);
parent_roots[appinfo->child_relid] = subroot;
continue;
}
/* Generate Path(s) for accessing this result relation */
grouping_planner(subroot, true, 0.0 /* retrieve all tuples */ );
/*
* Set the nomimal target relation of the ModifyTable node if not
* already done. We use the inheritance parent RTE as the nominal
* target relation if it's a partitioned table (see just above this
* loop). In the non-partitioned parent case, we'll use the first
* child relation (even if it's excluded) as the nominal target
* relation. Because of the way expand_inherited_rtentry works, the
* latter should be the RTE representing the parent table in its role
* as a simple member of the inheritance set.
*
* It would be logically cleaner to *always* use the inheritance
* parent RTE as the nominal relation; but that RTE is not otherwise
* referenced in the plan in the non-partitioned inheritance case.
* Instead the duplicate child RTE created by expand_inherited_rtentry
* is used elsewhere in the plan, so using the original parent RTE
* would give rise to confusing use of multiple aliases in EXPLAIN
* output for what the user will think is the "same" table. OTOH,
* it's not a problem in the partitioned inheritance case, because the
* duplicate child RTE added for the parent does not appear anywhere
* else in the plan tree.
*/
if (nominalRelation < 0)
nominalRelation = appinfo->child_relid;
/*
* Select cheapest path in case there's more than one. We always run
* modification queries to conclusion, so we care only for the
* cheapest-total path.
*/
sub_final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
set_cheapest(sub_final_rel);
subpath = sub_final_rel->cheapest_total_path;
/*
* If this child rel was excluded by constraint exclusion, exclude it
* from the result plan.
*/
if (IS_DUMMY_PATH(subpath))
continue;
/*
* If this is the first non-excluded child, its post-planning rtable
* becomes the initial contents of final_rtable; otherwise, append
* just its modified subquery RTEs to final_rtable.
*/
if (final_rtable == NIL)
final_rtable = subroot->parse->rtable;
else
final_rtable = list_concat(final_rtable,
list_copy_tail(subroot->parse->rtable,
list_length(final_rtable)));
/*
* We need to collect all the RelOptInfos from all child plans into
* the main PlannerInfo, since setrefs.c will need them. We use the
* last child's simple_rel_array (previous ones are too short), so we
* have to propagate forward the RelOptInfos that were already built
* in previous children.
*/
Assert(subroot->simple_rel_array_size >= save_rel_array_size);
for (rti = 1; rti < save_rel_array_size; rti++)
{
RelOptInfo *brel = save_rel_array[rti];
if (brel)
subroot->simple_rel_array[rti] = brel;
}
save_rel_array_size = subroot->simple_rel_array_size;
save_rel_array = subroot->simple_rel_array;
/* Make sure any initplans from this rel get into the outer list */
root->init_plans = subroot->init_plans;
/* Build list of sub-paths */
subpaths = lappend(subpaths, subpath);
/* Build list of modified subroots, too */
subroots = lappend(subroots, subroot);
/* Build list of target-relation RT indexes */
resultRelations = lappend_int(resultRelations, appinfo->child_relid);
/* Build lists of per-relation WCO and RETURNING targetlists */
if (parse->withCheckOptions)
withCheckOptionLists = lappend(withCheckOptionLists,
subroot->parse->withCheckOptions);
if (parse->returningList)
returningLists = lappend(returningLists,
subroot->parse->returningList);
Assert(!parse->onConflict);
}
/* Result path must go into outer query's FINAL upperrel */
final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
/*
* We don't currently worry about setting final_rel's consider_parallel
* flag in this case, nor about allowing FDWs or create_upper_paths_hook
* to get control here.
*/
/*
* If we managed to exclude every child rel, return a dummy plan; it
* doesn't even need a ModifyTable node.
*/
if (subpaths == NIL)
{
set_dummy_rel_pathlist(final_rel);
return;
}
/*
* Put back the final adjusted rtable into the master copy of the Query.
* (We mustn't do this if we found no non-excluded children.)
*/
parse->rtable = final_rtable;
root->simple_rel_array_size = save_rel_array_size;
root->simple_rel_array = save_rel_array;
/* Must reconstruct master's simple_rte_array, too */
root->simple_rte_array = (RangeTblEntry **)
palloc0((list_length(final_rtable) + 1) * sizeof(RangeTblEntry *));
rti = 1;
foreach(lc, final_rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
root->simple_rte_array[rti++] = rte;
}
/*
* If there was a FOR [KEY] UPDATE/SHARE clause, the LockRows node will
* have dealt with fetching non-locked marked rows, else we need to have
* ModifyTable do that.
*/
if (parse->rowMarks)
rowMarks = NIL;
else
rowMarks = root->rowMarks;
/* Create Path representing a ModifyTable to do the UPDATE/DELETE work */
add_path(final_rel, (Path *)
create_modifytable_path(root, final_rel,
parse->commandType,
parse->canSetTag,
nominalRelation,
partitioned_rels,
partColsUpdated,
resultRelations,
subpaths,
subroots,
withCheckOptionLists,
returningLists,
rowMarks,
NULL,
SS_assign_special_param(root)));
}
/*--------------------
* grouping_planner
* Perform planning steps related to grouping, aggregation, etc.
*
* This function adds all required top-level processing to the scan/join
* Path(s) produced by query_planner.
*
* If inheritance_update is true, we're being called from inheritance_planner
* and should not include a ModifyTable step in the resulting Path(s).
* (inheritance_planner will create a single ModifyTable node covering all the
* target tables.)
*
* tuple_fraction is the fraction of tuples we expect will be retrieved.
* tuple_fraction is interpreted as follows:
* 0: expect all tuples to be retrieved (normal case)
* 0 < tuple_fraction < 1: expect the given fraction of tuples available
* from the plan to be retrieved
* tuple_fraction >= 1: tuple_fraction is the absolute number of tuples
* expected to be retrieved (ie, a LIMIT specification)
*
* Returns nothing; the useful output is in the Paths we attach to the
* (UPPERREL_FINAL, NULL) upperrel in *root. In addition,
* root->processed_tlist contains the final processed targetlist.
*
* Note that we have not done set_cheapest() on the final rel; it's convenient
* to leave this to the caller.
*--------------------
*/
static void
grouping_planner(PlannerInfo *root, bool inheritance_update,
double tuple_fraction)
{
Query *parse = root->parse;
List *tlist;
int64 offset_est = 0;
int64 count_est = 0;
double limit_tuples = -1.0;
bool have_postponed_srfs = false;
PathTarget *final_target;
List *final_targets;
List *final_targets_contain_srfs;
RelOptInfo *current_rel;
RelOptInfo *final_rel;
ListCell *lc;
/* Tweak caller-supplied tuple_fraction if have LIMIT/OFFSET */
if (parse->limitCount || parse->limitOffset)
{
tuple_fraction = preprocess_limit(root, tuple_fraction,
&offset_est, &count_est);
/*
* If we have a known LIMIT, and don't have an unknown OFFSET, we can
* estimate the effects of using a bounded sort.
*/
if (count_est > 0 && offset_est >= 0)
limit_tuples = (double) count_est + (double) offset_est;
}
/* Make tuple_fraction accessible to lower-level routines */
root->tuple_fraction = tuple_fraction;
if (parse->setOperations)
{
/*
* If there's a top-level ORDER BY, assume we have to fetch all the
* tuples. This might be too simplistic given all the hackery below
* to possibly avoid the sort; but the odds of accurate estimates here
* are pretty low anyway. XXX try to get rid of this in favor of
* letting plan_set_operations generate both fast-start and
* cheapest-total paths.
*/
if (parse->sortClause)
root->tuple_fraction = 0.0;
/*
* Construct Paths for set operations. The results will not need any
* work except perhaps a top-level sort and/or LIMIT. Note that any
* special work for recursive unions is the responsibility of
* plan_set_operations.
*/
current_rel = plan_set_operations(root);
/*
* We should not need to call preprocess_targetlist, since we must be
* in a SELECT query node. Instead, use the targetlist returned by
* plan_set_operations (since this tells whether it returned any
* resjunk columns!), and transfer any sort key information from the
* original tlist.
*/
Assert(parse->commandType == CMD_SELECT);
tlist = root->processed_tlist; /* from plan_set_operations */
/* for safety, copy processed_tlist instead of modifying in-place */
tlist = postprocess_setop_tlist(copyObject(tlist), parse->targetList);
/* Save aside the final decorated tlist */
root->processed_tlist = tlist;
/* Also extract the PathTarget form of the setop result tlist */
final_target = current_rel->cheapest_total_path->pathtarget;
/* The setop result tlist couldn't contain any SRFs */
Assert(!parse->hasTargetSRFs);
final_targets = final_targets_contain_srfs = NIL;
/*
* Can't handle FOR [KEY] UPDATE/SHARE here (parser should have
* checked already, but let's make sure).
*/
if (parse->rowMarks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
/*------
translator: %s is a SQL row locking clause such as FOR UPDATE */
errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
LCS_asString(linitial_node(RowMarkClause,
parse->rowMarks)->strength))));
/*
* Calculate pathkeys that represent result ordering requirements
*/
Assert(parse->distinctClause == NIL);
root->sort_pathkeys = make_pathkeys_for_sortclauses(root,
parse->sortClause,
tlist);
}
else
{
/* No set operations, do regular planning */
PathTarget *sort_input_target;
List *sort_input_targets;
List *sort_input_targets_contain_srfs;
PathTarget *grouping_target;
List *grouping_targets;
List *grouping_targets_contain_srfs;
PathTarget *scanjoin_target;
List *scanjoin_targets;
List *scanjoin_targets_contain_srfs;
bool have_grouping;
AggClauseCosts agg_costs;
WindowFuncLists *wflists = NULL;
List *activeWindows = NIL;
grouping_sets_data *gset_data = NULL;
standard_qp_extra qp_extra;
/* A recursive query should always have setOperations */
Assert(!root->hasRecursion);
/* Preprocess grouping sets and GROUP BY clause, if any */
if (parse->groupingSets)
{
gset_data = preprocess_grouping_sets(root);
}
else
{
/* Preprocess regular GROUP BY clause, if any */
if (parse->groupClause)
parse->groupClause = preprocess_groupclause(root, NIL);
}
/* Preprocess targetlist */
tlist = preprocess_targetlist(root);
/*
* We are now done hacking up the query's targetlist. Most of the
* remaining planning work will be done with the PathTarget
* representation of tlists, but save aside the full representation so
* that we can transfer its decoration (resnames etc) to the topmost
* tlist of the finished Plan.
*/
root->processed_tlist = tlist;
/*
* Collect statistics about aggregates for estimating costs, and mark
* all the aggregates with resolved aggtranstypes. We must do this
* before slicing and dicing the tlist into various pathtargets, else
* some copies of the Aggref nodes might escape being marked with the
* correct transtypes.
*
* Note: currently, we do not detect duplicate aggregates here. This
* may result in somewhat-overestimated cost, which is fine for our
* purposes since all Paths will get charged the same. But at some
* point we might wish to do that detection in the planner, rather
* than during executor startup.
*/
MemSet(&agg_costs, 0, sizeof(AggClauseCosts));
if (parse->hasAggs)
{
get_agg_clause_costs(root, (Node *) tlist, AGGSPLIT_SIMPLE,
&agg_costs);
get_agg_clause_costs(root, parse->havingQual, AGGSPLIT_SIMPLE,
&agg_costs);
}
/*
* Locate any window functions in the tlist. (We don't need to look
* anywhere else, since expressions used in ORDER BY will be in there
* too.) Note that they could all have been eliminated by constant
* folding, in which case we don't need to do any more work.
*/
if (parse->hasWindowFuncs)
{
wflists = find_window_functions((Node *) tlist,
list_length(parse->windowClause));
if (wflists->numWindowFuncs > 0)
activeWindows = select_active_windows(root, wflists);
else
parse->hasWindowFuncs = false;
}
/*
* Preprocess MIN/MAX aggregates, if any. Note: be careful about
* adding logic between here and the query_planner() call. Anything
* that is needed in MIN/MAX-optimizable cases will have to be
* duplicated in planagg.c.
*/
if (parse->hasAggs)
preprocess_minmax_aggregates(root, tlist);
/*
* Figure out whether there's a hard limit on the number of rows that
* query_planner's result subplan needs to return. Even if we know a
* hard limit overall, it doesn't apply if the query has any
* grouping/aggregation operations, or SRFs in the tlist.
*/
if (parse->groupClause ||
parse->groupingSets ||
parse->distinctClause ||
parse->hasAggs ||
parse->hasWindowFuncs ||
parse->hasTargetSRFs ||
root->hasHavingQual)
root->limit_tuples = -1.0;
else
root->limit_tuples = limit_tuples;
/* Set up data needed by standard_qp_callback */
qp_extra.tlist = tlist;
qp_extra.activeWindows = activeWindows;
qp_extra.groupClause = (gset_data
? (gset_data->rollups ? linitial_node(RollupData, gset_data->rollups)->groupClause : NIL)
: parse->groupClause);
/*
* Generate the best unsorted and presorted paths for the scan/join
* portion of this Query, ie the processing represented by the
* FROM/WHERE clauses. (Note there may not be any presorted paths.)
* We also generate (in standard_qp_callback) pathkey representations
* of the query's sort clause, distinct clause, etc.
*/
current_rel = query_planner(root, tlist,
standard_qp_callback, &qp_extra);
/*
* Convert the query's result tlist into PathTarget format.
*
* Note: it's desirable to not do this till after query_planner(),
* because the target width estimates can use per-Var width numbers
* that were obtained within query_planner().
*/
final_target = create_pathtarget(root, tlist);
/*
* If ORDER BY was given, consider whether we should use a post-sort
* projection, and compute the adjusted target for preceding steps if
* so.
*/
if (parse->sortClause)
sort_input_target = make_sort_input_target(root,
final_target,
&have_postponed_srfs);
else
sort_input_target = final_target;
/*
* If we have window functions to deal with, the output from any
* grouping step needs to be what the window functions want;
* otherwise, it should be sort_input_target.
*/
if (activeWindows)
grouping_target = make_window_input_target(root,
final_target,
activeWindows);
else
grouping_target = sort_input_target;
/*
* If we have grouping or aggregation to do, the topmost scan/join
* plan node must emit what the grouping step wants; otherwise, it
* should emit grouping_target.
*/
have_grouping = (parse->groupClause || parse->groupingSets ||
parse->hasAggs || root->hasHavingQual);
if (have_grouping)
scanjoin_target = make_group_input_target(root, final_target);
else
scanjoin_target = grouping_target;
/*
* If there are any SRFs in the targetlist, we must separate each of
* these PathTargets into SRF-computing and SRF-free targets. Replace
* each of the named targets with a SRF-free version, and remember the
* list of additional projection steps we need to add afterwards.
*/
if (parse->hasTargetSRFs)
{
/* final_target doesn't recompute any SRFs in sort_input_target */
split_pathtarget_at_srfs(root, final_target, sort_input_target,
&final_targets,
&final_targets_contain_srfs);
final_target = linitial_node(PathTarget, final_targets);
Assert(!linitial_int(final_targets_contain_srfs));
/* likewise for sort_input_target vs. grouping_target */
split_pathtarget_at_srfs(root, sort_input_target, grouping_target,
&sort_input_targets,
&sort_input_targets_contain_srfs);
sort_input_target = linitial_node(PathTarget, sort_input_targets);
Assert(!linitial_int(sort_input_targets_contain_srfs));
/* likewise for grouping_target vs. scanjoin_target */
split_pathtarget_at_srfs(root, grouping_target, scanjoin_target,
&grouping_targets,
&grouping_targets_contain_srfs);
grouping_target = linitial_node(PathTarget, grouping_targets);
Assert(!linitial_int(grouping_targets_contain_srfs));
/* scanjoin_target will not have any SRFs precomputed for it */
split_pathtarget_at_srfs(root, scanjoin_target, NULL,
&scanjoin_targets,
&scanjoin_targets_contain_srfs);
scanjoin_target = linitial_node(PathTarget, scanjoin_targets);
Assert(!linitial_int(scanjoin_targets_contain_srfs));
}
else
{
/* initialize lists, just to keep compiler quiet */
final_targets = final_targets_contain_srfs = NIL;
sort_input_targets = sort_input_targets_contain_srfs = NIL;
grouping_targets = grouping_targets_contain_srfs = NIL;
scanjoin_targets = scanjoin_targets_contain_srfs = NIL;
}
/*
* Forcibly apply SRF-free scan/join target to all the Paths for the
* scan/join rel.
*
* In principle we should re-run set_cheapest() here to identify the
* cheapest path, but it seems unlikely that adding the same tlist
* eval costs to all the paths would change that, so we don't bother.
* Instead, just assume that the cheapest-startup and cheapest-total
* paths remain so. (There should be no parameterized paths anymore,
* so we needn't worry about updating cheapest_parameterized_paths.)
*/
foreach(lc, current_rel->pathlist)
{
Path *subpath = (Path *) lfirst(lc);
Path *path;
Assert(subpath->param_info == NULL);
path = apply_projection_to_path(root, current_rel,
subpath, scanjoin_target);
/* If we had to add a Result, path is different from subpath */
if (path != subpath)
{
lfirst(lc) = path;
if (subpath == current_rel->cheapest_startup_path)
current_rel->cheapest_startup_path = path;
if (subpath == current_rel->cheapest_total_path)
current_rel->cheapest_total_path = path;
}
}
/*
* Upper planning steps which make use of the top scan/join rel's
* partial pathlist will expect partial paths for that rel to produce
* the same output as complete paths ... and we just changed the
* output for the complete paths, so we'll need to do the same thing
* for partial paths. But only parallel-safe expressions can be
* computed by partial paths.
*/
if (current_rel->partial_pathlist &&
is_parallel_safe(root, (Node *) scanjoin_target->exprs))
{
/* Apply the scan/join target to each partial path */
foreach(lc, current_rel->partial_pathlist)
{
Path *subpath = (Path *) lfirst(lc);
Path *newpath;
/* Shouldn't have any parameterized paths anymore */
Assert(subpath->param_info == NULL);
/*
* Don't use apply_projection_to_path() here, because there
* could be other pointers to these paths, and therefore we
* mustn't modify them in place.
*/
newpath = (Path *) create_projection_path(root,
current_rel,
subpath,
scanjoin_target);
lfirst(lc) = newpath;
}
}
else
{
/*
* In the unfortunate event that scanjoin_target is not
* parallel-safe, we can't apply it to the partial paths; in that
* case, we'll need to forget about the partial paths, which
* aren't valid input for upper planning steps.
*/
current_rel->partial_pathlist = NIL;
}
/* Now fix things up if scan/join target contains SRFs */
if (parse->hasTargetSRFs)
adjust_paths_for_srfs(root, current_rel,
scanjoin_targets,
scanjoin_targets_contain_srfs);
/*
* Save the various upper-rel PathTargets we just computed into
* root->upper_targets[]. The core code doesn't use this, but it
* provides a convenient place for extensions to get at the info. For
* consistency, we save all the intermediate targets, even though some
* of the corresponding upperrels might not be needed for this query.
*/
root->upper_targets[UPPERREL_FINAL] = final_target;
root->upper_targets[UPPERREL_WINDOW] = sort_input_target;
root->upper_targets[UPPERREL_GROUP_AGG] = grouping_target;
/*
* If we have grouping and/or aggregation, consider ways to implement
* that. We build a new upperrel representing the output of this
* phase.
*/
if (have_grouping)
{
current_rel = create_grouping_paths(root,
current_rel,
grouping_target,
&agg_costs,
gset_data);
/* Fix things up if grouping_target contains SRFs */
if (parse->hasTargetSRFs)
adjust_paths_for_srfs(root, current_rel,
grouping_targets,
grouping_targets_contain_srfs);
}
/*
* If we have window functions, consider ways to implement those. We
* build a new upperrel representing the output of this phase.
*/
if (activeWindows)
{
current_rel = create_window_paths(root,
current_rel,
grouping_target,
sort_input_target,
tlist,
wflists,
activeWindows);
/* Fix things up if sort_input_target contains SRFs */
if (parse->hasTargetSRFs)
adjust_paths_for_srfs(root, current_rel,
sort_input_targets,
sort_input_targets_contain_srfs);
}
/*
* If there is a DISTINCT clause, consider ways to implement that. We
* build a new upperrel representing the output of this phase.
*/
if (parse->distinctClause)
{
current_rel = create_distinct_paths(root,
current_rel);
}
} /* end of if (setOperations) */
/*
* If ORDER BY was given, consider ways to implement that, and generate a
* new upperrel containing only paths that emit the correct ordering and
* project the correct final_target. We can apply the original
* limit_tuples limit in sort costing here, but only if there are no
* postponed SRFs.
*/
if (parse->sortClause)
{
current_rel = create_ordered_paths(root,
current_rel,
final_target,
have_postponed_srfs ? -1.0 :
limit_tuples);
/* Fix things up if final_target contains SRFs */
if (parse->hasTargetSRFs)
adjust_paths_for_srfs(root, current_rel,
final_targets,
final_targets_contain_srfs);
}
/*
* Now we are prepared to build the final-output upperrel.
*/
final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
/*
* If the input rel is marked consider_parallel and there's nothing that's
* not parallel-safe in the LIMIT clause, then the final_rel can be marked
* consider_parallel as well. Note that if the query has rowMarks or is
* not a SELECT, consider_parallel will be false for every relation in the
* query.
*/
if (current_rel->consider_parallel &&
is_parallel_safe(root, parse->limitOffset) &&
is_parallel_safe(root, parse->limitCount))
final_rel->consider_parallel = true;
/*
* If the current_rel belongs to a single FDW, so does the final_rel.
*/
final_rel->serverid = current_rel->serverid;
final_rel->userid = current_rel->userid;
final_rel->useridiscurrent = current_rel->useridiscurrent;
final_rel->fdwroutine = current_rel->fdwroutine;
/*
* Generate paths for the final_rel. Insert all surviving paths, with
* LockRows, Limit, and/or ModifyTable steps added if needed.
*/
foreach(lc, current_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
/*
* If there is a FOR [KEY] UPDATE/SHARE clause, add the LockRows node.
* (Note: we intentionally test parse->rowMarks not root->rowMarks
* here. If there are only non-locking rowmarks, they should be
* handled by the ModifyTable node instead. However, root->rowMarks
* is what goes into the LockRows node.)
*/
if (parse->rowMarks)
{
path = (Path *) create_lockrows_path(root, final_rel, path,
root->rowMarks,
SS_assign_special_param(root));
}
/*
* If there is a LIMIT/OFFSET clause, add the LIMIT node.
*/
if (limit_needed(parse))
{
path = (Path *) create_limit_path(root, final_rel, path,
parse->limitOffset,
parse->limitCount,
offset_est, count_est);
}
/*
* If this is an INSERT/UPDATE/DELETE, and we're not being called from
* inheritance_planner, add the ModifyTable node.
*/
if (parse->commandType != CMD_SELECT && !inheritance_update)
{
List *withCheckOptionLists;
List *returningLists;
List *rowMarks;
/*
* Set up the WITH CHECK OPTION and RETURNING lists-of-lists, if
* needed.
*/
if (parse->withCheckOptions)
withCheckOptionLists = list_make1(parse->withCheckOptions);
else
withCheckOptionLists = NIL;
if (parse->returningList)
returningLists = list_make1(parse->returningList);
else
returningLists = NIL;
/*
* If there was a FOR [KEY] UPDATE/SHARE clause, the LockRows node
* will have dealt with fetching non-locked marked rows, else we
* need to have ModifyTable do that.
*/
if (parse->rowMarks)
rowMarks = NIL;
else
rowMarks = root->rowMarks;
path = (Path *)
create_modifytable_path(root, final_rel,
parse->commandType,
parse->canSetTag,
parse->resultRelation,
NIL,
false,
list_make1_int(parse->resultRelation),
list_make1(path),
list_make1(root),
withCheckOptionLists,
returningLists,
rowMarks,
parse->onConflict,
SS_assign_special_param(root));
}
/* And shove it into final_rel */
add_path(final_rel, path);
}
/*
* If there is an FDW that's responsible for all baserels of the query,
* let it consider adding ForeignPaths.
*/
if (final_rel->fdwroutine &&
final_rel->fdwroutine->GetForeignUpperPaths)
final_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_FINAL,
current_rel, final_rel);
/* Let extensions possibly add some more paths */
if (create_upper_paths_hook)
(*create_upper_paths_hook) (root, UPPERREL_FINAL,
current_rel, final_rel);
/* Note: currently, we leave it to callers to do set_cheapest() */
}
/*
* Do preprocessing for groupingSets clause and related data. This handles the
* preliminary steps of expanding the grouping sets, organizing them into lists
* of rollups, and preparing annotations which will later be filled in with
* size estimates.
*/
static grouping_sets_data *
preprocess_grouping_sets(PlannerInfo *root)
{
Query *parse = root->parse;
List *sets;
int maxref = 0;
ListCell *lc;
ListCell *lc_set;
grouping_sets_data *gd = palloc0(sizeof(grouping_sets_data));
parse->groupingSets = expand_grouping_sets(parse->groupingSets, -1);
gd->any_hashable = false;
gd->unhashable_refs = NULL;
gd->unsortable_refs = NULL;
gd->unsortable_sets = NIL;
if (parse->groupClause)
{
ListCell *lc;
foreach(lc, parse->groupClause)
{
SortGroupClause *gc = lfirst_node(SortGroupClause, lc);
Index ref = gc->tleSortGroupRef;
if (ref > maxref)
maxref = ref;
if (!gc->hashable)
gd->unhashable_refs = bms_add_member(gd->unhashable_refs, ref);
if (!OidIsValid(gc->sortop))
gd->unsortable_refs = bms_add_member(gd->unsortable_refs, ref);
}
}
/* Allocate workspace array for remapping */
gd->tleref_to_colnum_map = (int *) palloc((maxref + 1) * sizeof(int));
/*
* If we have any unsortable sets, we must extract them before trying to
* prepare rollups. Unsortable sets don't go through
* reorder_grouping_sets, so we must apply the GroupingSetData annotation
* here.
*/
if (!bms_is_empty(gd->unsortable_refs))
{
List *sortable_sets = NIL;
foreach(lc, parse->groupingSets)
{
List *gset = (List *) lfirst(lc);
if (bms_overlap_list(gd->unsortable_refs, gset))
{
GroupingSetData *gs = makeNode(GroupingSetData);
gs->set = gset;
gd->unsortable_sets = lappend(gd->unsortable_sets, gs);
/*
* We must enforce here that an unsortable set is hashable;
* later code assumes this. Parse analysis only checks that
* every individual column is either hashable or sortable.
*
* Note that passing this test doesn't guarantee we can
* generate a plan; there might be other showstoppers.
*/
if (bms_overlap_list(gd->unhashable_refs, gset))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not implement GROUP BY"),
errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
}
else
sortable_sets = lappend(sortable_sets, gset);
}
if (sortable_sets)
sets = extract_rollup_sets(sortable_sets);
else
sets = NIL;
}
else
sets = extract_rollup_sets(parse->groupingSets);
foreach(lc_set, sets)
{
List *current_sets = (List *) lfirst(lc_set);
RollupData *rollup = makeNode(RollupData);
GroupingSetData *gs;
/*
* Reorder the current list of grouping sets into correct prefix
* order. If only one aggregation pass is needed, try to make the
* list match the ORDER BY clause; if more than one pass is needed, we
* don't bother with that.
*
* Note that this reorders the sets from smallest-member-first to
* largest-member-first, and applies the GroupingSetData annotations,
* though the data will be filled in later.
*/
current_sets = reorder_grouping_sets(current_sets,
(list_length(sets) == 1
? parse->sortClause
: NIL));
/*
* Get the initial (and therefore largest) grouping set.
*/
gs = linitial_node(GroupingSetData, current_sets);
/*
* Order the groupClause appropriately. If the first grouping set is
* empty, then the groupClause must also be empty; otherwise we have
* to force the groupClause to match that grouping set's order.
*
* (The first grouping set can be empty even though parse->groupClause
* is not empty only if all non-empty grouping sets are unsortable.
* The groupClauses for hashed grouping sets are built later on.)
*/
if (gs->set)
rollup->groupClause = preprocess_groupclause(root, gs->set);
else
rollup->groupClause = NIL;
/*
* Is it hashable? We pretend empty sets are hashable even though we
* actually force them not to be hashed later. But don't bother if
* there's nothing but empty sets (since in that case we can't hash
* anything).
*/
if (gs->set &&
!bms_overlap_list(gd->unhashable_refs, gs->set))
{
rollup->hashable = true;
gd->any_hashable = true;
}
/*
* Now that we've pinned down an order for the groupClause for this
* list of grouping sets, we need to remap the entries in the grouping
* sets from sortgrouprefs to plain indices (0-based) into the
* groupClause for this collection of grouping sets. We keep the
* original form for later use, though.
*/
rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
current_sets,
gd->tleref_to_colnum_map);
rollup->gsets_data = current_sets;
gd->rollups = lappend(gd->rollups, rollup);
}
if (gd->unsortable_sets)
{
/*
* We have not yet pinned down a groupclause for this, but we will
* need index-based lists for estimation purposes. Construct
* hash_sets_idx based on the entire original groupclause for now.
*/
gd->hash_sets_idx = remap_to_groupclause_idx(parse->groupClause,
gd->unsortable_sets,
gd->tleref_to_colnum_map);
gd->any_hashable = true;
}
return gd;
}
/*
* Given a groupclause and a list of GroupingSetData, return equivalent sets
* (without annotation) mapped to indexes into the given groupclause.
*/
static List *
remap_to_groupclause_idx(List *groupClause,
List *gsets,
int *tleref_to_colnum_map)
{
int ref = 0;
List *result = NIL;
ListCell *lc;
foreach(lc, groupClause)
{
SortGroupClause *gc = lfirst_node(SortGroupClause, lc);
tleref_to_colnum_map[gc->tleSortGroupRef] = ref++;
}
foreach(lc, gsets)
{
List *set = NIL;
ListCell *lc2;
GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
foreach(lc2, gs->set)
{
set = lappend_int(set, tleref_to_colnum_map[lfirst_int(lc2)]);
}
result = lappend(result, set);
}
return result;
}
/*
* Detect whether a plan node is a "dummy" plan created when a relation
* is deemed not to need scanning due to constraint exclusion.
*
* Currently, such dummy plans are Result nodes with constant FALSE
* filter quals (see set_dummy_rel_pathlist and create_append_plan).
*
* XXX this probably ought to be somewhere else, but not clear where.
*/
bool
is_dummy_plan(Plan *plan)
{
if (IsA(plan, Result))
{
List *rcqual = (List *) ((Result *) plan)->resconstantqual;
if (list_length(rcqual) == 1)
{
Const *constqual = (Const *) linitial(rcqual);
if (constqual && IsA(constqual, Const))
{
if (!constqual->constisnull &&
!DatumGetBool(constqual->constvalue))
return true;
}
}
}
return false;
}
/*
* preprocess_rowmarks - set up PlanRowMarks if needed
*/
static void
preprocess_rowmarks(PlannerInfo *root)
{
Query *parse = root->parse;
Bitmapset *rels;
List *prowmarks;
ListCell *l;
int i;
if (parse->rowMarks)
{
/*
* We've got trouble if FOR [KEY] UPDATE/SHARE appears inside
* grouping, since grouping renders a reference to individual tuple
* CTIDs invalid. This is also checked at parse time, but that's
* insufficient because of rule substitution, query pullup, etc.
*/
CheckSelectLocking(parse, linitial_node(RowMarkClause,
parse->rowMarks)->strength);
}
else
{
/*
* We only need rowmarks for UPDATE, DELETE, or FOR [KEY]
* UPDATE/SHARE.
*/
if (parse->commandType != CMD_UPDATE &&
parse->commandType != CMD_DELETE)
return;
}
/*
* We need to have rowmarks for all base relations except the target. We
* make a bitmapset of all base rels and then remove the items we don't
* need or have FOR [KEY] UPDATE/SHARE marks for.
*/
rels = get_relids_in_jointree((Node *) parse->jointree, false);
if (parse->resultRelation)
rels = bms_del_member(rels, parse->resultRelation);
/*
* Convert RowMarkClauses to PlanRowMark representation.
*/
prowmarks = NIL;
foreach(l, parse->rowMarks)
{
RowMarkClause *rc = lfirst_node(RowMarkClause, l);
RangeTblEntry *rte = rt_fetch(rc->rti, parse->rtable);
PlanRowMark *newrc;
/*
* Currently, it is syntactically impossible to have FOR UPDATE et al
* applied to an update/delete target rel. If that ever becomes
* possible, we should drop the target from the PlanRowMark list.
*/
Assert(rc->rti != parse->resultRelation);
/*
* Ignore RowMarkClauses for subqueries; they aren't real tables and
* can't support true locking. Subqueries that got flattened into the
* main query should be ignored completely. Any that didn't will get
* ROW_MARK_COPY items in the next loop.
*/
if (rte->rtekind != RTE_RELATION)
continue;
rels = bms_del_member(rels, rc->rti);
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = rc->rti;
newrc->rowmarkId = ++(root->glob->lastRowMarkId);
newrc->markType = select_rowmark_type(rte, rc->strength);
newrc->allMarkTypes = (1 << newrc->markType);
newrc->strength = rc->strength;
newrc->waitPolicy = rc->waitPolicy;
newrc->isParent = false;
prowmarks = lappend(prowmarks, newrc);
}
/*
* Now, add rowmarks for any non-target, non-locked base relations.
*/
i = 0;
foreach(l, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
PlanRowMark *newrc;
i++;
if (!bms_is_member(i, rels))
continue;
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = i;
newrc->rowmarkId = ++(root->glob->lastRowMarkId);
newrc->markType = select_rowmark_type(rte, LCS_NONE);
newrc->allMarkTypes = (1 << newrc->markType);
newrc->strength = LCS_NONE;
newrc->waitPolicy = LockWaitBlock; /* doesn't matter */
newrc->isParent = false;
prowmarks = lappend(prowmarks, newrc);
}
root->rowMarks = prowmarks;
}
/*
* Select RowMarkType to use for a given table
*/
RowMarkType
select_rowmark_type(RangeTblEntry *rte, LockClauseStrength strength)
{
if (rte->rtekind != RTE_RELATION)
{
/* If it's not a table at all, use ROW_MARK_COPY */
return ROW_MARK_COPY;
}
else if (rte->relkind == RELKIND_FOREIGN_TABLE)
{
/* Let the FDW select the rowmark type, if it wants to */
FdwRoutine *fdwroutine = GetFdwRoutineByRelId(rte->relid);
if (fdwroutine->GetForeignRowMarkType != NULL)
return fdwroutine->GetForeignRowMarkType(rte, strength);
/* Otherwise, use ROW_MARK_COPY by default */
return ROW_MARK_COPY;
}
else
{
/* Regular table, apply the appropriate lock type */
switch (strength)
{
case LCS_NONE:
/*
* We don't need a tuple lock, only the ability to re-fetch
* the row.
*/
return ROW_MARK_REFERENCE;
break;
case LCS_FORKEYSHARE:
return ROW_MARK_KEYSHARE;
break;
case LCS_FORSHARE:
return ROW_MARK_SHARE;
break;
case LCS_FORNOKEYUPDATE:
return ROW_MARK_NOKEYEXCLUSIVE;
break;
case LCS_FORUPDATE:
return ROW_MARK_EXCLUSIVE;
break;
}
elog(ERROR, "unrecognized LockClauseStrength %d", (int) strength);
return ROW_MARK_EXCLUSIVE; /* keep compiler quiet */
}
}
/*
* preprocess_limit - do pre-estimation for LIMIT and/or OFFSET clauses
*
* We try to estimate the values of the LIMIT/OFFSET clauses, and pass the
* results back in *count_est and *offset_est. These variables are set to
* 0 if the corresponding clause is not present, and -1 if it's present
* but we couldn't estimate the value for it. (The "0" convention is OK
* for OFFSET but a little bit bogus for LIMIT: effectively we estimate
* LIMIT 0 as though it were LIMIT 1. But this is in line with the planner's
* usual practice of never estimating less than one row.) These values will
* be passed to create_limit_path, which see if you change this code.
*
* The return value is the suitably adjusted tuple_fraction to use for
* planning the query. This adjustment is not overridable, since it reflects
* plan actions that grouping_planner() will certainly take, not assumptions
* about context.
*/
static double
preprocess_limit(PlannerInfo *root, double tuple_fraction,
int64 *offset_est, int64 *count_est)
{
Query *parse = root->parse;
Node *est;
double limit_fraction;
/* Should not be called unless LIMIT or OFFSET */
Assert(parse->limitCount || parse->limitOffset);
/*
* Try to obtain the clause values. We use estimate_expression_value
* primarily because it can sometimes do something useful with Params.
*/
if (parse->limitCount)
{
est = estimate_expression_value(root, parse->limitCount);
if (est && IsA(est, Const))
{
if (((Const *) est)->constisnull)
{
/* NULL indicates LIMIT ALL, ie, no limit */
*count_est = 0; /* treat as not present */
}
else
{
*count_est = DatumGetInt64(((Const *) est)->constvalue);
if (*count_est <= 0)
*count_est = 1; /* force to at least 1 */
}
}
else
*count_est = -1; /* can't estimate */
}
else
*count_est = 0; /* not present */
if (parse->limitOffset)
{
est = estimate_expression_value(root, parse->limitOffset);
if (est && IsA(est, Const))
{
if (((Const *) est)->constisnull)
{
/* Treat NULL as no offset; the executor will too */
*offset_est = 0; /* treat as not present */
}
else
{
*offset_est = DatumGetInt64(((Const *) est)->constvalue);
if (*offset_est < 0)
*offset_est = 0; /* treat as not present */
}
}
else
*offset_est = -1; /* can't estimate */
}
else
*offset_est = 0; /* not present */
if (*count_est != 0)
{
/*
* A LIMIT clause limits the absolute number of tuples returned.
* However, if it's not a constant LIMIT then we have to guess; for
* lack of a better idea, assume 10% of the plan's result is wanted.
*/
if (*count_est < 0 || *offset_est < 0)
{
/* LIMIT or OFFSET is an expression ... punt ... */
limit_fraction = 0.10;
}
else
{
/* LIMIT (plus OFFSET, if any) is max number of tuples needed */
limit_fraction = (double) *count_est + (double) *offset_est;
}
/*
* If we have absolute limits from both caller and LIMIT, use the
* smaller value; likewise if they are both fractional. If one is
* fractional and the other absolute, we can't easily determine which
* is smaller, but we use the heuristic that the absolute will usually
* be smaller.
*/
if (tuple_fraction >= 1.0)
{
if (limit_fraction >= 1.0)
{
/* both absolute */
tuple_fraction = Min(tuple_fraction, limit_fraction);
}
else
{
/* caller absolute, limit fractional; use caller's value */
}
}
else if (tuple_fraction > 0.0)
{
if (limit_fraction >= 1.0)
{
/* caller fractional, limit absolute; use limit */
tuple_fraction = limit_fraction;
}
else
{
/* both fractional */
tuple_fraction = Min(tuple_fraction, limit_fraction);
}
}
else
{
/* no info from caller, just use limit */
tuple_fraction = limit_fraction;
}
}
else if (*offset_est != 0 && tuple_fraction > 0.0)
{
/*
* We have an OFFSET but no LIMIT. This acts entirely differently
* from the LIMIT case: here, we need to increase rather than decrease
* the caller's tuple_fraction, because the OFFSET acts to cause more
* tuples to be fetched instead of fewer. This only matters if we got
* a tuple_fraction > 0, however.
*
* As above, use 10% if OFFSET is present but unestimatable.
*/
if (*offset_est < 0)
limit_fraction = 0.10;
else
limit_fraction = (double) *offset_est;
/*
* If we have absolute counts from both caller and OFFSET, add them
* together; likewise if they are both fractional. If one is
* fractional and the other absolute, we want to take the larger, and
* we heuristically assume that's the fractional one.
*/
if (tuple_fraction >= 1.0)
{
if (limit_fraction >= 1.0)
{
/* both absolute, so add them together */
tuple_fraction += limit_fraction;
}
else
{
/* caller absolute, limit fractional; use limit */
tuple_fraction = limit_fraction;
}
}
else
{
if (limit_fraction >= 1.0)
{
/* caller fractional, limit absolute; use caller's value */
}
else
{
/* both fractional, so add them together */
tuple_fraction += limit_fraction;
if (tuple_fraction >= 1.0)
tuple_fraction = 0.0; /* assume fetch all */
}
}
}
return tuple_fraction;
}
/*
* limit_needed - do we actually need a Limit plan node?
*
* If we have constant-zero OFFSET and constant-null LIMIT, we can skip adding
* a Limit node. This is worth checking for because "OFFSET 0" is a common
* locution for an optimization fence. (Because other places in the planner
* merely check whether parse->limitOffset isn't NULL, it will still work as
* an optimization fence --- we're just suppressing unnecessary run-time
* overhead.)
*
* This might look like it could be merged into preprocess_limit, but there's
* a key distinction: here we need hard constants in OFFSET/LIMIT, whereas
* in preprocess_limit it's good enough to consider estimated values.
*/
static bool
limit_needed(Query *parse)
{
Node *node;
node = parse->limitCount;
if (node)
{
if (IsA(node, Const))
{
/* NULL indicates LIMIT ALL, ie, no limit */
if (!((Const *) node)->constisnull)
return true; /* LIMIT with a constant value */
}
else
return true; /* non-constant LIMIT */
}
node = parse->limitOffset;
if (node)
{
if (IsA(node, Const))
{
/* Treat NULL as no offset; the executor would too */
if (!((Const *) node)->constisnull)
{
int64 offset = DatumGetInt64(((Const *) node)->constvalue);
if (offset != 0)
return true; /* OFFSET with a nonzero value */
}
}
else
return true; /* non-constant OFFSET */
}
return false; /* don't need a Limit plan node */
}
/*
* remove_useless_groupby_columns
* Remove any columns in the GROUP BY clause that are redundant due to
* being functionally dependent on other GROUP BY columns.
*
* Since some other DBMSes do not allow references to ungrouped columns, it's
* not unusual to find all columns listed in GROUP BY even though listing the
* primary-key columns would be sufficient. Deleting such excess columns
* avoids redundant sorting work, so it's worth doing. When we do this, we
* must mark the plan as dependent on the pkey constraint (compare the
* parser's check_ungrouped_columns() and check_functional_grouping()).
*
* In principle, we could treat any NOT-NULL columns appearing in a UNIQUE
* index as the determining columns. But as with check_functional_grouping(),
* there's currently no way to represent dependency on a NOT NULL constraint,
* so we consider only the pkey for now.
*/
static void
remove_useless_groupby_columns(PlannerInfo *root)
{
Query *parse = root->parse;
Bitmapset **groupbyattnos;
Bitmapset **surplusvars;
ListCell *lc;
int relid;
/* No chance to do anything if there are less than two GROUP BY items */
if (list_length(parse->groupClause) < 2)
return;
/* Don't fiddle with the GROUP BY clause if the query has grouping sets */
if (parse->groupingSets)
return;
/*
* Scan the GROUP BY clause to find GROUP BY items that are simple Vars.
* Fill groupbyattnos[k] with a bitmapset of the column attnos of RTE k
* that are GROUP BY items.
*/
groupbyattnos = (Bitmapset **) palloc0(sizeof(Bitmapset *) *
(list_length(parse->rtable) + 1));
foreach(lc, parse->groupClause)
{
SortGroupClause *sgc = lfirst_node(SortGroupClause, lc);
TargetEntry *tle = get_sortgroupclause_tle(sgc, parse->targetList);
Var *var = (Var *) tle->expr;
/*
* Ignore non-Vars and Vars from other query levels.
*
* XXX in principle, stable expressions containing Vars could also be
* removed, if all the Vars are functionally dependent on other GROUP
* BY items. But it's not clear that such cases occur often enough to
* be worth troubling over.
*/
if (!IsA(var, Var) ||
var->varlevelsup > 0)
continue;
/* OK, remember we have this Var */
relid = var->varno;
Assert(relid <= list_length(parse->rtable));
groupbyattnos[relid] = bms_add_member(groupbyattnos[relid],
var->varattno - FirstLowInvalidHeapAttributeNumber);
}
/*
* Consider each relation and see if it is possible to remove some of its
* Vars from GROUP BY. For simplicity and speed, we do the actual removal
* in a separate pass. Here, we just fill surplusvars[k] with a bitmapset
* of the column attnos of RTE k that are removable GROUP BY items.
*/
surplusvars = NULL; /* don't allocate array unless required */
relid = 0;
foreach(lc, parse->rtable)
{
RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
Bitmapset *relattnos;
Bitmapset *pkattnos;
Oid constraintOid;
relid++;
/* Only plain relations could have primary-key constraints */
if (rte->rtekind != RTE_RELATION)
continue;
/* Nothing to do unless this rel has multiple Vars in GROUP BY */
relattnos = groupbyattnos[relid];
if (bms_membership(relattnos) != BMS_MULTIPLE)
continue;
/*
* Can't remove any columns for this rel if there is no suitable
* (i.e., nondeferrable) primary key constraint.
*/
pkattnos = get_primary_key_attnos(rte->relid, false, &constraintOid);
if (pkattnos == NULL)
continue;
/*
* If the primary key is a proper subset of relattnos then we have
* some items in the GROUP BY that can be removed.
*/
if (bms_subset_compare(pkattnos, relattnos) == BMS_SUBSET1)
{
/*
* To easily remember whether we've found anything to do, we don't
* allocate the surplusvars[] array until we find something.
*/
if (surplusvars == NULL)
surplusvars = (Bitmapset **) palloc0(sizeof(Bitmapset *) *
(list_length(parse->rtable) + 1));
/* Remember the attnos of the removable columns */
surplusvars[relid] = bms_difference(relattnos, pkattnos);
/* Also, mark the resulting plan as dependent on this constraint */
parse->constraintDeps = lappend_oid(parse->constraintDeps,
constraintOid);
}
}
/*
* If we found any surplus Vars, build a new GROUP BY clause without them.
* (Note: this may leave some TLEs with unreferenced ressortgroupref
* markings, but that's harmless.)
*/
if (surplusvars != NULL)
{
List *new_groupby = NIL;
foreach(lc, parse->groupClause)
{
SortGroupClause *sgc = lfirst_node(SortGroupClause, lc);
TargetEntry *tle = get_sortgroupclause_tle(sgc, parse->targetList);
Var *var = (Var *) tle->expr;
/*
* New list must include non-Vars, outer Vars, and anything not
* marked as surplus.
*/
if (!IsA(var, Var) ||
var->varlevelsup > 0 ||
!bms_is_member(var->varattno - FirstLowInvalidHeapAttributeNumber,
surplusvars[var->varno]))
new_groupby = lappend(new_groupby, sgc);
}
parse->groupClause = new_groupby;
}
}
/*
* preprocess_groupclause - do preparatory work on GROUP BY clause
*
* The idea here is to adjust the ordering of the GROUP BY elements
* (which in itself is semantically insignificant) to match ORDER BY,
* thereby allowing a single sort operation to both implement the ORDER BY
* requirement and set up for a Unique step that implements GROUP BY.
*
* In principle it might be interesting to consider other orderings of the
* GROUP BY elements, which could match the sort ordering of other
* possible plans (eg an indexscan) and thereby reduce cost. We don't
* bother with that, though. Hashed grouping will frequently win anyway.
*
* Note: we need no comparable processing of the distinctClause because
* the parser already enforced that that matches ORDER BY.
*
* For grouping sets, the order of items is instead forced to agree with that
* of the grouping set (and items not in the grouping set are skipped). The
* work of sorting the order of grouping set elements to match the ORDER BY if
* possible is done elsewhere.
*/
static List *
preprocess_groupclause(PlannerInfo *root, List *force)
{
Query *parse = root->parse;
List *new_groupclause = NIL;
bool partial_match;
ListCell *sl;
ListCell *gl;
/* For grouping sets, we need to force the ordering */
if (force)
{
foreach(sl, force)
{
Index ref = lfirst_int(sl);
SortGroupClause *cl = get_sortgroupref_clause(ref, parse->groupClause);
new_groupclause = lappend(new_groupclause, cl);
}
return new_groupclause;
}
/* If no ORDER BY, nothing useful to do here */
if (parse->sortClause == NIL)
return parse->groupClause;
/*
* Scan the ORDER BY clause and construct a list of matching GROUP BY
* items, but only as far as we can make a matching prefix.
*
* This code assumes that the sortClause contains no duplicate items.
*/
foreach(sl, parse->sortClause)
{
SortGroupClause *sc = lfirst_node(SortGroupClause, sl);
foreach(gl, parse->groupClause)
{
SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
if (equal(gc, sc))
{
new_groupclause = lappend(new_groupclause, gc);
break;
}
}
if (gl == NULL)
break; /* no match, so stop scanning */
}
/* Did we match all of the ORDER BY list, or just some of it? */
partial_match = (sl != NULL);
/* If no match at all, no point in reordering GROUP BY */
if (new_groupclause == NIL)
return parse->groupClause;
/*
* Add any remaining GROUP BY items to the new list, but only if we were
* able to make a complete match. In other words, we only rearrange the
* GROUP BY list if the result is that one list is a prefix of the other
* --- otherwise there's no possibility of a common sort. Also, give up
* if there are any non-sortable GROUP BY items, since then there's no
* hope anyway.
*/
foreach(gl, parse->groupClause)
{
SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
if (list_member_ptr(new_groupclause, gc))
continue; /* it matched an ORDER BY item */
if (partial_match)
return parse->groupClause; /* give up, no common sort possible */
if (!OidIsValid(gc->sortop))
return parse->groupClause; /* give up, GROUP BY can't be sorted */
new_groupclause = lappend(new_groupclause, gc);
}
/* Success --- install the rearranged GROUP BY list */
Assert(list_length(parse->groupClause) == list_length(new_groupclause));
return new_groupclause;
}
/*
* Extract lists of grouping sets that can be implemented using a single
* rollup-type aggregate pass each. Returns a list of lists of grouping sets.
*
* Input must be sorted with smallest sets first. Result has each sublist
* sorted with smallest sets first.
*
* We want to produce the absolute minimum possible number of lists here to
* avoid excess sorts. Fortunately, there is an algorithm for this; the problem
* of finding the minimal partition of a partially-ordered set into chains
* (which is what we need, taking the list of grouping sets as a poset ordered
* by set inclusion) can be mapped to the problem of finding the maximum
* cardinality matching on a bipartite graph, which is solvable in polynomial
* time with a worst case of no worse than O(n^2.5) and usually much
* better. Since our N is at most 4096, we don't need to consider fallbacks to
* heuristic or approximate methods. (Planning time for a 12-d cube is under
* half a second on my modest system even with optimization off and assertions
* on.)
*/
static List *
extract_rollup_sets(List *groupingSets)
{
int num_sets_raw = list_length(groupingSets);
int num_empty = 0;
int num_sets = 0; /* distinct sets */
int num_chains = 0;
List *result = NIL;
List **results;
List **orig_sets;
Bitmapset **set_masks;
int *chains;
short **adjacency;
short *adjacency_buf;
BipartiteMatchState *state;
int i;
int j;
int j_size;
ListCell *lc1 = list_head(groupingSets);
ListCell *lc;
/*
* Start by stripping out empty sets. The algorithm doesn't require this,
* but the planner currently needs all empty sets to be returned in the
* first list, so we strip them here and add them back after.
*/
while (lc1 && lfirst(lc1) == NIL)
{
++num_empty;
lc1 = lnext(lc1);
}
/* bail out now if it turns out that all we had were empty sets. */
if (!lc1)
return list_make1(groupingSets);
/*----------
* We don't strictly need to remove duplicate sets here, but if we don't,
* they tend to become scattered through the result, which is a bit
* confusing (and irritating if we ever decide to optimize them out).
* So we remove them here and add them back after.
*
* For each non-duplicate set, we fill in the following:
*
* orig_sets[i] = list of the original set lists
* set_masks[i] = bitmapset for testing inclusion
* adjacency[i] = array [n, v1, v2, ... vn] of adjacency indices
*
* chains[i] will be the result group this set is assigned to.
*
* We index all of these from 1 rather than 0 because it is convenient
* to leave 0 free for the NIL node in the graph algorithm.
*----------
*/
orig_sets = palloc0((num_sets_raw + 1) * sizeof(List *));
set_masks = palloc0((num_sets_raw + 1) * sizeof(Bitmapset *));
adjacency = palloc0((num_sets_raw + 1) * sizeof(short *));
adjacency_buf = palloc((num_sets_raw + 1) * sizeof(short));
j_size = 0;
j = 0;
i = 1;
for_each_cell(lc, lc1)
{
List *candidate = (List *) lfirst(lc);
Bitmapset *candidate_set = NULL;
ListCell *lc2;
int dup_of = 0;
foreach(lc2, candidate)
{
candidate_set = bms_add_member(candidate_set, lfirst_int(lc2));
}
/* we can only be a dup if we're the same length as a previous set */
if (j_size == list_length(candidate))
{
int k;
for (k = j; k < i; ++k)
{
if (bms_equal(set_masks[k], candidate_set))
{
dup_of = k;
break;
}
}
}
else if (j_size < list_length(candidate))
{
j_size = list_length(candidate);
j = i;
}
if (dup_of > 0)
{
orig_sets[dup_of] = lappend(orig_sets[dup_of], candidate);
bms_free(candidate_set);
}
else
{
int k;
int n_adj = 0;
orig_sets[i] = list_make1(candidate);
set_masks[i] = candidate_set;
/* fill in adjacency list; no need to compare equal-size sets */
for (k = j - 1; k > 0; --k)
{
if (bms_is_subset(set_masks[k], candidate_set))
adjacency_buf[++n_adj] = k;
}
if (n_adj > 0)
{
adjacency_buf[0] = n_adj;
adjacency[i] = palloc((n_adj + 1) * sizeof(short));
memcpy(adjacency[i], adjacency_buf, (n_adj + 1) * sizeof(short));
}
else
adjacency[i] = NULL;
++i;
}
}
num_sets = i - 1;
/*
* Apply the graph matching algorithm to do the work.
*/
state = BipartiteMatch(num_sets, num_sets, adjacency);
/*
* Now, the state->pair* fields have the info we need to assign sets to
* chains. Two sets (u,v) belong to the same chain if pair_uv[u] = v or
* pair_vu[v] = u (both will be true, but we check both so that we can do
* it in one pass)
*/
chains = palloc0((num_sets + 1) * sizeof(int));
for (i = 1; i <= num_sets; ++i)
{
int u = state->pair_vu[i];
int v = state->pair_uv[i];
if (u > 0 && u < i)
chains[i] = chains[u];
else if (v > 0 && v < i)
chains[i] = chains[v];
else
chains[i] = ++num_chains;
}
/* build result lists. */
results = palloc0((num_chains + 1) * sizeof(List *));
for (i = 1; i <= num_sets; ++i)
{
int c = chains[i];
Assert(c > 0);
results[c] = list_concat(results[c], orig_sets[i]);
}
/* push any empty sets back on the first list. */
while (num_empty-- > 0)
results[1] = lcons(NIL, results[1]);
/* make result list */
for (i = 1; i <= num_chains; ++i)
result = lappend(result, results[i]);
/*
* Free all the things.
*
* (This is over-fussy for small sets but for large sets we could have
* tied up a nontrivial amount of memory.)
*/
BipartiteMatchFree(state);
pfree(results);
pfree(chains);
for (i = 1; i <= num_sets; ++i)
if (adjacency[i])
pfree(adjacency[i]);
pfree(adjacency);
pfree(adjacency_buf);
pfree(orig_sets);
for (i = 1; i <= num_sets; ++i)
bms_free(set_masks[i]);
pfree(set_masks);
return result;
}
/*
* Reorder the elements of a list of grouping sets such that they have correct
* prefix relationships. Also inserts the GroupingSetData annotations.
*
* The input must be ordered with smallest sets first; the result is returned
* with largest sets first. Note that the result shares no list substructure
* with the input, so it's safe for the caller to modify it later.
*
* If we're passed in a sortclause, we follow its order of columns to the
* extent possible, to minimize the chance that we add unnecessary sorts.
* (We're trying here to ensure that GROUPING SETS ((a,b,c),(c)) ORDER BY c,b,a
* gets implemented in one pass.)
*/
static List *
reorder_grouping_sets(List *groupingsets, List *sortclause)
{
ListCell *lc;
ListCell *lc2;
List *previous = NIL;
List *result = NIL;
foreach(lc, groupingsets)
{
List *candidate = (List *) lfirst(lc);
List *new_elems = list_difference_int(candidate, previous);
GroupingSetData *gs = makeNode(GroupingSetData);
if (list_length(new_elems) > 0)
{
while (list_length(sortclause) > list_length(previous))
{
SortGroupClause *sc = list_nth(sortclause, list_length(previous));
int ref = sc->tleSortGroupRef;
if (list_member_int(new_elems, ref))
{
previous = lappend_int(previous, ref);
new_elems = list_delete_int(new_elems, ref);
}
else
{
/* diverged from the sortclause; give up on it */
sortclause = NIL;
break;
}
}
foreach(lc2, new_elems)
{
previous = lappend_int(previous, lfirst_int(lc2));
}
}
gs->set = list_copy(previous);
result = lcons(gs, result);
list_free(new_elems);
}
list_free(previous);
return result;
}
/*
* Compute query_pathkeys and other pathkeys during plan generation
*/
static void
standard_qp_callback(PlannerInfo *root, void *extra)
{
Query *parse = root->parse;
standard_qp_extra *qp_extra = (standard_qp_extra *) extra;
List *tlist = qp_extra->tlist;
List *activeWindows = qp_extra->activeWindows;
/*
* Calculate pathkeys that represent grouping/ordering requirements. The
* sortClause is certainly sort-able, but GROUP BY and DISTINCT might not
* be, in which case we just leave their pathkeys empty.
*/
if (qp_extra->groupClause &&
grouping_is_sortable(qp_extra->groupClause))
root->group_pathkeys =
make_pathkeys_for_sortclauses(root,
qp_extra->groupClause,
tlist);
else
root->group_pathkeys = NIL;
/* We consider only the first (bottom) window in pathkeys logic */
if (activeWindows != NIL)
{
WindowClause *wc = linitial_node(WindowClause, activeWindows);
root->window_pathkeys = make_pathkeys_for_window(root,
wc,
tlist);
}
else
root->window_pathkeys = NIL;
if (parse->distinctClause &&
grouping_is_sortable(parse->distinctClause))
root->distinct_pathkeys =
make_pathkeys_for_sortclauses(root,
parse->distinctClause,
tlist);
else
root->distinct_pathkeys = NIL;
root->sort_pathkeys =
make_pathkeys_for_sortclauses(root,
parse->sortClause,
tlist);
/*
* Figure out whether we want a sorted result from query_planner.
*
* If we have a sortable GROUP BY clause, then we want a result sorted
* properly for grouping. Otherwise, if we have window functions to
* evaluate, we try to sort for the first window. Otherwise, if there's a
* sortable DISTINCT clause that's more rigorous than the ORDER BY clause,
* we try to produce output that's sufficiently well sorted for the
* DISTINCT. Otherwise, if there is an ORDER BY clause, we want to sort
* by the ORDER BY clause.
*
* Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a superset
* of GROUP BY, it would be tempting to request sort by ORDER BY --- but
* that might just leave us failing to exploit an available sort order at
* all. Needs more thought. The choice for DISTINCT versus ORDER BY is
* much easier, since we know that the parser ensured that one is a
* superset of the other.
*/
if (root->group_pathkeys)
root->query_pathkeys = root->group_pathkeys;
else if (root->window_pathkeys)
root->query_pathkeys = root->window_pathkeys;
else if (list_length(root->distinct_pathkeys) >
list_length(root->sort_pathkeys))
root->query_pathkeys = root->distinct_pathkeys;
else if (root->sort_pathkeys)
root->query_pathkeys = root->sort_pathkeys;
else
root->query_pathkeys = NIL;
}
/*
* Estimate number of groups produced by grouping clauses (1 if not grouping)
*
* path_rows: number of output rows from scan/join step
* gsets: grouping set data, or NULL if not doing grouping sets
*
* If doing grouping sets, we also annotate the gsets data with the estimates
* for each set and each individual rollup list, with a view to later
* determining whether some combination of them could be hashed instead.
*/
static double
get_number_of_groups(PlannerInfo *root,
double path_rows,
grouping_sets_data *gd)
{
Query *parse = root->parse;
double dNumGroups;
if (parse->groupClause)
{
List *groupExprs;
if (parse->groupingSets)
{
/* Add up the estimates for each grouping set */
ListCell *lc;
ListCell *lc2;
Assert(gd); /* keep Coverity happy */
dNumGroups = 0;
foreach(lc, gd->rollups)
{
RollupData *rollup = lfirst_node(RollupData, lc);
ListCell *lc;
groupExprs = get_sortgrouplist_exprs(rollup->groupClause,
parse->targetList);
rollup->numGroups = 0.0;
forboth(lc, rollup->gsets, lc2, rollup->gsets_data)
{
List *gset = (List *) lfirst(lc);
GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
double numGroups = estimate_num_groups(root,
groupExprs,
path_rows,
&gset);
gs->numGroups = numGroups;
rollup->numGroups += numGroups;
}
dNumGroups += rollup->numGroups;
}
if (gd->hash_sets_idx)
{
ListCell *lc;
gd->dNumHashGroups = 0;
groupExprs = get_sortgrouplist_exprs(parse->groupClause,
parse->targetList);
forboth(lc, gd->hash_sets_idx, lc2, gd->unsortable_sets)
{
List *gset = (List *) lfirst(lc);
GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
double numGroups = estimate_num_groups(root,
groupExprs,
path_rows,
&gset);
gs->numGroups = numGroups;
gd->dNumHashGroups += numGroups;
}
dNumGroups += gd->dNumHashGroups;
}
}
else
{
/* Plain GROUP BY */
groupExprs = get_sortgrouplist_exprs(parse->groupClause,
parse->targetList);
dNumGroups = estimate_num_groups(root, groupExprs, path_rows,
NULL);
}
}
else if (parse->groupingSets)
{
/* Empty grouping sets ... one result row for each one */
dNumGroups = list_length(parse->groupingSets);
}
else if (parse->hasAggs || root->hasHavingQual)
{
/* Plain aggregation, one result row */
dNumGroups = 1;
}
else
{
/* Not grouping */
dNumGroups = 1;
}
return dNumGroups;
}
/*
* estimate_hashagg_tablesize
* estimate the number of bytes that a hash aggregate hashtable will
* require based on the agg_costs, path width and dNumGroups.
*
* XXX this may be over-estimating the size now that hashagg knows to omit
* unneeded columns from the hashtable. Also for mixed-mode grouping sets,
* grouping columns not in the hashed set are counted here even though hashagg
* won't store them. Is this a problem?
*/
static Size
estimate_hashagg_tablesize(Path *path, const AggClauseCosts *agg_costs,
double dNumGroups)
{
Size hashentrysize;
/* Estimate per-hash-entry space at tuple width... */
hashentrysize = MAXALIGN(path->pathtarget->width) +
MAXALIGN(SizeofMinimalTupleHeader);
/* plus space for pass-by-ref transition values... */
hashentrysize += agg_costs->transitionSpace;
/* plus the per-hash-entry overhead */
hashentrysize += hash_agg_entry_size(agg_costs->numAggs);
/*
* Note that this disregards the effect of fill-factor and growth policy
* of the hash-table. That's probably ok, given default the default
* fill-factor is relatively high. It'd be hard to meaningfully factor in
* "double-in-size" growth policies here.
*/
return hashentrysize * dNumGroups;
}
/*
* create_grouping_paths
*
* Build a new upperrel containing Paths for grouping and/or aggregation.
*
* input_rel: contains the source-data Paths
* target: the pathtarget for the result Paths to compute
* agg_costs: cost info about all aggregates in query (in AGGSPLIT_SIMPLE mode)
* rollup_lists: list of grouping sets, or NIL if not doing grouping sets
* rollup_groupclauses: list of grouping clauses for grouping sets,
* or NIL if not doing grouping sets
*
* Note: all Paths in input_rel are expected to return the target computed
* by make_group_input_target.
*
* We need to consider sorted and hashed aggregation in the same function,
* because otherwise (1) it would be harder to throw an appropriate error
* message if neither way works, and (2) we should not allow hashtable size
* considerations to dissuade us from using hashing if sorting is not possible.
*/
static RelOptInfo *
create_grouping_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *target,
const AggClauseCosts *agg_costs,
grouping_sets_data *gd)
{
Query *parse = root->parse;
Path *cheapest_path = input_rel->cheapest_total_path;
RelOptInfo *grouped_rel;
PathTarget *partial_grouping_target = NULL;
AggClauseCosts agg_partial_costs; /* parallel only */
AggClauseCosts agg_final_costs; /* parallel only */
double dNumGroups;
bool can_hash;
bool can_sort;
bool try_parallel_aggregation;
/* For now, do all work in the (GROUP_AGG, NULL) upperrel */
grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, NULL);
/*
* If the input relation is not parallel-safe, then the grouped relation
* can't be parallel-safe, either. Otherwise, it's parallel-safe if the
* target list and HAVING quals are parallel-safe.
*/
if (input_rel->consider_parallel &&
is_parallel_safe(root, (Node *) target->exprs) &&
is_parallel_safe(root, (Node *) parse->havingQual))
grouped_rel->consider_parallel = true;
/*
* If the input rel belongs to a single FDW, so does the grouped rel.
*/
grouped_rel->serverid = input_rel->serverid;
grouped_rel->userid = input_rel->userid;
grouped_rel->useridiscurrent = input_rel->useridiscurrent;
grouped_rel->fdwroutine = input_rel->fdwroutine;
/*
* Check for degenerate grouping.
*/
if ((root->hasHavingQual || parse->groupingSets) &&
!parse->hasAggs && parse->groupClause == NIL)
{
/*
* We have a HAVING qual and/or grouping sets, but no aggregates and
* no GROUP BY (which implies that the grouping sets are all empty).
*
* This is a degenerate case in which we are supposed to emit either
* zero or one row for each grouping set depending on whether HAVING
* succeeds. Furthermore, there cannot be any variables in either
* HAVING or the targetlist, so we actually do not need the FROM table
* at all! We can just throw away the plan-so-far and generate a
* Result node. This is a sufficiently unusual corner case that it's
* not worth contorting the structure of this module to avoid having
* to generate the earlier paths in the first place.
*/
int nrows = list_length(parse->groupingSets);
Path *path;
if (nrows > 1)
{
/*
* Doesn't seem worthwhile writing code to cons up a
* generate_series or a values scan to emit multiple rows. Instead
* just make N clones and append them. (With a volatile HAVING
* clause, this means you might get between 0 and N output rows.
* Offhand I think that's desired.)
*/
List *paths = NIL;
while (--nrows >= 0)
{
path = (Path *)
create_result_path(root, grouped_rel,
target,
(List *) parse->havingQual);
paths = lappend(paths, path);
}
path = (Path *)
create_append_path(grouped_rel,
paths,
NIL,
NULL,
0,
false,
NIL,
-1);
path->pathtarget = target;
}
else
{
/* No grouping sets, or just one, so one output row */
path = (Path *)
create_result_path(root, grouped_rel,
target,
(List *) parse->havingQual);
}
add_path(grouped_rel, path);
/* No need to consider any other alternatives. */
set_cheapest(grouped_rel);
return grouped_rel;
}
/*
* Estimate number of groups.
*/
dNumGroups = get_number_of_groups(root,
cheapest_path->rows,
gd);
/*
* Determine whether it's possible to perform sort-based implementations
* of grouping. (Note that if groupClause is empty,
* grouping_is_sortable() is trivially true, and all the
* pathkeys_contained_in() tests will succeed too, so that we'll consider
* every surviving input path.)
*
* If we have grouping sets, we might be able to sort some but not all of
* them; in this case, we need can_sort to be true as long as we must
* consider any sorted-input plan.
*/
can_sort = (gd && gd->rollups != NIL)
|| grouping_is_sortable(parse->groupClause);
/*
* Determine whether we should consider hash-based implementations of
* grouping.
*
* Hashed aggregation only applies if we're grouping. If we have grouping
* sets, some groups might be hashable but others not; in this case we set
* can_hash true as long as there is nothing globally preventing us from
* hashing (and we should therefore consider plans with hashes).
*
* Executor doesn't support hashed aggregation with DISTINCT or ORDER BY
* aggregates. (Doing so would imply storing *all* the input values in
* the hash table, and/or running many sorts in parallel, either of which
* seems like a certain loser.) We similarly don't support ordered-set
* aggregates in hashed aggregation, but that case is also included in the
* numOrderedAggs count.
*
* Note: grouping_is_hashable() is much more expensive to check than the
* other gating conditions, so we want to do it last.
*/
can_hash = (parse->groupClause != NIL &&
agg_costs->numOrderedAggs == 0 &&
(gd ? gd->any_hashable : grouping_is_hashable(parse->groupClause)));
/*
* Figure out whether a PartialAggregate/Finalize Aggregate execution
* strategy is viable.
*/
try_parallel_aggregation = can_parallel_agg(root, input_rel, grouped_rel,
agg_costs);
/*
* Before generating paths for grouped_rel, we first generate any possible
* partial paths; that way, later code can easily consider both parallel
* and non-parallel approaches to grouping. Note that the partial paths
* we generate here are also partially aggregated, so simply pushing a
* Gather node on top is insufficient to create a final path, as would be
* the case for a scan/join rel.
*/
if (try_parallel_aggregation)
{
/*
* Build target list for partial aggregate paths. These paths cannot
* just emit the same tlist as regular aggregate paths, because (1) we
* must include Vars and Aggrefs needed in HAVING, which might not
* appear in the result tlist, and (2) the Aggrefs must be set in
* partial mode.
*/
partial_grouping_target = make_partial_grouping_target(root, target);
/*
* Collect statistics about aggregates for estimating costs of
* performing aggregation in parallel.
*/
MemSet(&agg_partial_costs, 0, sizeof(AggClauseCosts));
MemSet(&agg_final_costs, 0, sizeof(AggClauseCosts));
if (parse->hasAggs)
{
/* partial phase */
get_agg_clause_costs(root, (Node *) partial_grouping_target->exprs,
AGGSPLIT_INITIAL_SERIAL,
&agg_partial_costs);
/* final phase */
get_agg_clause_costs(root, (Node *) target->exprs,
AGGSPLIT_FINAL_DESERIAL,
&agg_final_costs);
get_agg_clause_costs(root, parse->havingQual,
AGGSPLIT_FINAL_DESERIAL,
&agg_final_costs);
}
add_partial_paths_to_grouping_rel(root, input_rel, grouped_rel, target,
partial_grouping_target,
&agg_partial_costs, &agg_final_costs,
gd, can_sort, can_hash,
(List *) parse->havingQual);
}
/* Build final grouping paths */
add_paths_to_grouping_rel(root, input_rel, grouped_rel, target,
partial_grouping_target, agg_costs,
&agg_final_costs, gd, can_sort, can_hash,
dNumGroups, (List *) parse->havingQual);
/* Give a helpful error if we failed to find any implementation */
if (grouped_rel->pathlist == NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not implement GROUP BY"),
errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
/*
* If there is an FDW that's responsible for all baserels of the query,
* let it consider adding ForeignPaths.
*/
if (grouped_rel->fdwroutine &&
grouped_rel->fdwroutine->GetForeignUpperPaths)
grouped_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_GROUP_AGG,
input_rel, grouped_rel);
/* Let extensions possibly add some more paths */
if (create_upper_paths_hook)
(*create_upper_paths_hook) (root, UPPERREL_GROUP_AGG,
input_rel, grouped_rel);
/* Now choose the best path(s) */
set_cheapest(grouped_rel);
/*
* We've been using the partial pathlist for the grouped relation to hold
* partially aggregated paths, but that's actually a little bit bogus
* because it's unsafe for later planning stages -- like ordered_rel ---
* to get the idea that they can use these partial paths as if they didn't
* need a FinalizeAggregate step. Zap the partial pathlist at this stage
* so we don't get confused.
*/
grouped_rel->partial_pathlist = NIL;
return grouped_rel;
}
/*
* For a given input path, consider the possible ways of doing grouping sets on
* it, by combinations of hashing and sorting. This can be called multiple
* times, so it's important that it not scribble on input. No result is
* returned, but any generated paths are added to grouped_rel.
*/
static void
consider_groupingsets_paths(PlannerInfo *root,
RelOptInfo *grouped_rel,
Path *path,
bool is_sorted,
bool can_hash,
PathTarget *target,
grouping_sets_data *gd,
const AggClauseCosts *agg_costs,
double dNumGroups)
{
Query *parse = root->parse;
/*
* If we're not being offered sorted input, then only consider plans that
* can be done entirely by hashing.
*
* We can hash everything if it looks like it'll fit in work_mem. But if
* the input is actually sorted despite not being advertised as such, we
* prefer to make use of that in order to use less memory.
*
* If none of the grouping sets are sortable, then ignore the work_mem
* limit and generate a path anyway, since otherwise we'll just fail.
*/
if (!is_sorted)
{
List *new_rollups = NIL;
RollupData *unhashed_rollup = NULL;
List *sets_data;
List *empty_sets_data = NIL;
List *empty_sets = NIL;
ListCell *lc;
ListCell *l_start = list_head(gd->rollups);
AggStrategy strat = AGG_HASHED;
Size hashsize;
double exclude_groups = 0.0;
Assert(can_hash);
if (pathkeys_contained_in(root->group_pathkeys, path->pathkeys))
{
unhashed_rollup = lfirst_node(RollupData, l_start);
exclude_groups = unhashed_rollup->numGroups;
l_start = lnext(l_start);
}
hashsize = estimate_hashagg_tablesize(path,
agg_costs,
dNumGroups - exclude_groups);
/*
* gd->rollups is empty if we have only unsortable columns to work
* with. Override work_mem in that case; otherwise, we'll rely on the
* sorted-input case to generate usable mixed paths.
*/
if (hashsize > work_mem * 1024L && gd->rollups)
return; /* nope, won't fit */
/*
* We need to burst the existing rollups list into individual grouping
* sets and recompute a groupClause for each set.
*/
sets_data = list_copy(gd->unsortable_sets);
for_each_cell(lc, l_start)
{
RollupData *rollup = lfirst_node(RollupData, lc);
/*
* If we find an unhashable rollup that's not been skipped by the
* "actually sorted" check above, we can't cope; we'd need sorted
* input (with a different sort order) but we can't get that here.
* So bail out; we'll get a valid path from the is_sorted case
* instead.
*
* The mere presence of empty grouping sets doesn't make a rollup
* unhashable (see preprocess_grouping_sets), we handle those
* specially below.
*/
if (!rollup->hashable)
return;
else
sets_data = list_concat(sets_data, list_copy(rollup->gsets_data));
}
foreach(lc, sets_data)
{
GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
List *gset = gs->set;
RollupData *rollup;
if (gset == NIL)
{
/* Empty grouping sets can't be hashed. */
empty_sets_data = lappend(empty_sets_data, gs);
empty_sets = lappend(empty_sets, NIL);
}
else
{
rollup = makeNode(RollupData);
rollup->groupClause = preprocess_groupclause(root, gset);
rollup->gsets_data = list_make1(gs);
rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
rollup->gsets_data,
gd->tleref_to_colnum_map);
rollup->numGroups = gs->numGroups;
rollup->hashable = true;
rollup->is_hashed = true;
new_rollups = lappend(new_rollups, rollup);
}
}
/*
* If we didn't find anything nonempty to hash, then bail. We'll
* generate a path from the is_sorted case.
*/
if (new_rollups == NIL)
return;
/*
* If there were empty grouping sets they should have been in the
* first rollup.
*/
Assert(!unhashed_rollup || !empty_sets);
if (unhashed_rollup)
{
new_rollups = lappend(new_rollups, unhashed_rollup);
strat = AGG_MIXED;
}
else if (empty_sets)
{
RollupData *rollup = makeNode(RollupData);
rollup->groupClause = NIL;
rollup->gsets_data = empty_sets_data;
rollup->gsets = empty_sets;
rollup->numGroups = list_length(empty_sets);
rollup->hashable = false;
rollup->is_hashed = false;
new_rollups = lappend(new_rollups, rollup);
strat = AGG_MIXED;
}
add_path(grouped_rel, (Path *)
create_groupingsets_path(root,
grouped_rel,
path,
target,
(List *) parse->havingQual,
strat,
new_rollups,
agg_costs,
dNumGroups));
return;
}
/*
* If we have sorted input but nothing we can do with it, bail.
*/
if (list_length(gd->rollups) == 0)
return;
/*
* Given sorted input, we try and make two paths: one sorted and one mixed
* sort/hash. (We need to try both because hashagg might be disabled, or
* some columns might not be sortable.)
*
* can_hash is passed in as false if some obstacle elsewhere (such as
* ordered aggs) means that we shouldn't consider hashing at all.
*/
if (can_hash && gd->any_hashable)
{
List *rollups = NIL;
List *hash_sets = list_copy(gd->unsortable_sets);
double availspace = (work_mem * 1024.0);
ListCell *lc;
/*
* Account first for space needed for groups we can't sort at all.
*/
availspace -= (double) estimate_hashagg_tablesize(path,
agg_costs,
gd->dNumHashGroups);
if (availspace > 0 && list_length(gd->rollups) > 1)
{
double scale;
int num_rollups = list_length(gd->rollups);
int k_capacity;
int *k_weights = palloc(num_rollups * sizeof(int));
Bitmapset *hash_items = NULL;
int i;
/*
* We treat this as a knapsack problem: the knapsack capacity
* represents work_mem, the item weights are the estimated memory
* usage of the hashtables needed to implement a single rollup,
* and we really ought to use the cost saving as the item value;
* however, currently the costs assigned to sort nodes don't
* reflect the comparison costs well, and so we treat all items as
* of equal value (each rollup we hash instead saves us one sort).
*
* To use the discrete knapsack, we need to scale the values to a
* reasonably small bounded range. We choose to allow a 5% error
* margin; we have no more than 4096 rollups in the worst possible
* case, which with a 5% error margin will require a bit over 42MB
* of workspace. (Anyone wanting to plan queries that complex had
* better have the memory for it. In more reasonable cases, with
* no more than a couple of dozen rollups, the memory usage will
* be negligible.)
*
* k_capacity is naturally bounded, but we clamp the values for
* scale and weight (below) to avoid overflows or underflows (or
* uselessly trying to use a scale factor less than 1 byte).
*/
scale = Max(availspace / (20.0 * num_rollups), 1.0);
k_capacity = (int) floor(availspace / scale);
/*
* We leave the first rollup out of consideration since it's the
* one that matches the input sort order. We assign indexes "i"
* to only those entries considered for hashing; the second loop,
* below, must use the same condition.
*/
i = 0;
for_each_cell(lc, lnext(list_head(gd->rollups)))
{
RollupData *rollup = lfirst_node(RollupData, lc);
if (rollup->hashable)
{
double sz = estimate_hashagg_tablesize(path,
agg_costs,
rollup->numGroups);
/*
* If sz is enormous, but work_mem (and hence scale) is
* small, avoid integer overflow here.
*/
k_weights[i] = (int) Min(floor(sz / scale),
k_capacity + 1.0);
++i;
}
}
/*
* Apply knapsack algorithm; compute the set of items which
* maximizes the value stored (in this case the number of sorts
* saved) while keeping the total size (approximately) within
* capacity.
*/
if (i > 0)
hash_items = DiscreteKnapsack(k_capacity, i, k_weights, NULL);
if (!bms_is_empty(hash_items))
{
rollups = list_make1(linitial(gd->rollups));
i = 0;
for_each_cell(lc, lnext(list_head(gd->rollups)))
{
RollupData *rollup = lfirst_node(RollupData, lc);
if (rollup->hashable)
{
if (bms_is_member(i, hash_items))
hash_sets = list_concat(hash_sets,
list_copy(rollup->gsets_data));
else
rollups = lappend(rollups, rollup);
++i;
}
else
rollups = lappend(rollups, rollup);
}
}
}
if (!rollups && hash_sets)
rollups = list_copy(gd->rollups);
foreach(lc, hash_sets)
{
GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
RollupData *rollup = makeNode(RollupData);
Assert(gs->set != NIL);
rollup->groupClause = preprocess_groupclause(root, gs->set);
rollup->gsets_data = list_make1(gs);
rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
rollup->gsets_data,
gd->tleref_to_colnum_map);
rollup->numGroups = gs->numGroups;
rollup->hashable = true;
rollup->is_hashed = true;
rollups = lcons(rollup, rollups);
}
if (rollups)
{
add_path(grouped_rel, (Path *)
create_groupingsets_path(root,
grouped_rel,
path,
target,
(List *) parse->havingQual,
AGG_MIXED,
rollups,
agg_costs,
dNumGroups));
}
}
/*
* Now try the simple sorted case.
*/
if (!gd->unsortable_sets)
add_path(grouped_rel, (Path *)
create_groupingsets_path(root,
grouped_rel,
path,
target,
(List *) parse->havingQual,
AGG_SORTED,
gd->rollups,
agg_costs,
dNumGroups));
}
/*
* create_window_paths
*
* Build a new upperrel containing Paths for window-function evaluation.
*
* input_rel: contains the source-data Paths
* input_target: result of make_window_input_target
* output_target: what the topmost WindowAggPath should return
* tlist: query's target list (needed to look up pathkeys)
* wflists: result of find_window_functions
* activeWindows: result of select_active_windows
*
* Note: all Paths in input_rel are expected to return input_target.
*/
static RelOptInfo *
create_window_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *input_target,
PathTarget *output_target,
List *tlist,
WindowFuncLists *wflists,
List *activeWindows)
{
RelOptInfo *window_rel;
ListCell *lc;
/* For now, do all work in the (WINDOW, NULL) upperrel */
window_rel = fetch_upper_rel(root, UPPERREL_WINDOW, NULL);
/*
* If the input relation is not parallel-safe, then the window relation
* can't be parallel-safe, either. Otherwise, we need to examine the
* target list and active windows for non-parallel-safe constructs.
*/
if (input_rel->consider_parallel &&
is_parallel_safe(root, (Node *) output_target->exprs) &&
is_parallel_safe(root, (Node *) activeWindows))
window_rel->consider_parallel = true;
/*
* If the input rel belongs to a single FDW, so does the window rel.
*/
window_rel->serverid = input_rel->serverid;
window_rel->userid = input_rel->userid;
window_rel->useridiscurrent = input_rel->useridiscurrent;
window_rel->fdwroutine = input_rel->fdwroutine;
/*
* Consider computing window functions starting from the existing
* cheapest-total path (which will likely require a sort) as well as any
* existing paths that satisfy root->window_pathkeys (which won't).
*/
foreach(lc, input_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
if (path == input_rel->cheapest_total_path ||
pathkeys_contained_in(root->window_pathkeys, path->pathkeys))
create_one_window_path(root,
window_rel,
path,
input_target,
output_target,
tlist,
wflists,
activeWindows);
}
/*
* If there is an FDW that's responsible for all baserels of the query,
* let it consider adding ForeignPaths.
*/
if (window_rel->fdwroutine &&
window_rel->fdwroutine->GetForeignUpperPaths)
window_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_WINDOW,
input_rel, window_rel);
/* Let extensions possibly add some more paths */
if (create_upper_paths_hook)
(*create_upper_paths_hook) (root, UPPERREL_WINDOW,
input_rel, window_rel);
/* Now choose the best path(s) */
set_cheapest(window_rel);
return window_rel;
}
/*
* Stack window-function implementation steps atop the given Path, and
* add the result to window_rel.
*
* window_rel: upperrel to contain result
* path: input Path to use (must return input_target)
* input_target: result of make_window_input_target
* output_target: what the topmost WindowAggPath should return
* tlist: query's target list (needed to look up pathkeys)
* wflists: result of find_window_functions
* activeWindows: result of select_active_windows
*/
static void
create_one_window_path(PlannerInfo *root,
RelOptInfo *window_rel,
Path *path,
PathTarget *input_target,
PathTarget *output_target,
List *tlist,
WindowFuncLists *wflists,
List *activeWindows)
{
PathTarget *window_target;
ListCell *l;
/*
* Since each window clause could require a different sort order, we stack
* up a WindowAgg node for each clause, with sort steps between them as
* needed. (We assume that select_active_windows chose a good order for
* executing the clauses in.)
*
* input_target should contain all Vars and Aggs needed for the result.
* (In some cases we wouldn't need to propagate all of these all the way
* to the top, since they might only be needed as inputs to WindowFuncs.
* It's probably not worth trying to optimize that though.) It must also
* contain all window partitioning and sorting expressions, to ensure
* they're computed only once at the bottom of the stack (that's critical
* for volatile functions). As we climb up the stack, we'll add outputs
* for the WindowFuncs computed at each level.
*/
window_target = input_target;
foreach(l, activeWindows)
{
WindowClause *wc = lfirst_node(WindowClause, l);
List *window_pathkeys;
window_pathkeys = make_pathkeys_for_window(root,
wc,
tlist);
/* Sort if necessary */
if (!pathkeys_contained_in(window_pathkeys, path->pathkeys))
{
path = (Path *) create_sort_path(root, window_rel,
path,
window_pathkeys,
-1.0);
}
if (lnext(l))
{
/*
* Add the current WindowFuncs to the output target for this
* intermediate WindowAggPath. We must copy window_target to
* avoid changing the previous path's target.
*
* Note: a WindowFunc adds nothing to the target's eval costs; but
* we do need to account for the increase in tlist width.
*/
ListCell *lc2;
window_target = copy_pathtarget(window_target);
foreach(lc2, wflists->windowFuncs[wc->winref])
{
WindowFunc *wfunc = lfirst_node(WindowFunc, lc2);
add_column_to_pathtarget(window_target, (Expr *) wfunc, 0);
window_target->width += get_typavgwidth(wfunc->wintype, -1);
}
}
else
{
/* Install the goal target in the topmost WindowAgg */
window_target = output_target;
}
path = (Path *)
create_windowagg_path(root, window_rel, path, window_target,
wflists->windowFuncs[wc->winref],
wc,
window_pathkeys);
}
add_path(window_rel, path);
}
/*
* create_distinct_paths
*
* Build a new upperrel containing Paths for SELECT DISTINCT evaluation.
*
* input_rel: contains the source-data Paths
*
* Note: input paths should already compute the desired pathtarget, since
* Sort/Unique won't project anything.
*/
static RelOptInfo *
create_distinct_paths(PlannerInfo *root,
RelOptInfo *input_rel)
{
Query *parse = root->parse;
Path *cheapest_input_path = input_rel->cheapest_total_path;
RelOptInfo *distinct_rel;
double numDistinctRows;
bool allow_hash;
Path *path;
ListCell *lc;
/* For now, do all work in the (DISTINCT, NULL) upperrel */
distinct_rel = fetch_upper_rel(root, UPPERREL_DISTINCT, NULL);
/*
* We don't compute anything at this level, so distinct_rel will be
* parallel-safe if the input rel is parallel-safe. In particular, if
* there is a DISTINCT ON (...) clause, any path for the input_rel will
* output those expressions, and will not be parallel-safe unless those
* expressions are parallel-safe.
*/
distinct_rel->consider_parallel = input_rel->consider_parallel;
/*
* If the input rel belongs to a single FDW, so does the distinct_rel.
*/
distinct_rel->serverid = input_rel->serverid;
distinct_rel->userid = input_rel->userid;
distinct_rel->useridiscurrent = input_rel->useridiscurrent;
distinct_rel->fdwroutine = input_rel->fdwroutine;
/* Estimate number of distinct rows there will be */
if (parse->groupClause || parse->groupingSets || parse->hasAggs ||
root->hasHavingQual)
{
/*
* If there was grouping or aggregation, use the number of input rows
* as the estimated number of DISTINCT rows (ie, assume the input is
* already mostly unique).
*/
numDistinctRows = cheapest_input_path->rows;
}
else
{
/*
* Otherwise, the UNIQUE filter has effects comparable to GROUP BY.
*/
List *distinctExprs;
distinctExprs = get_sortgrouplist_exprs(parse->distinctClause,
parse->targetList);
numDistinctRows = estimate_num_groups(root, distinctExprs,
cheapest_input_path->rows,
NULL);
}
/*
* Consider sort-based implementations of DISTINCT, if possible.
*/
if (grouping_is_sortable(parse->distinctClause))
{
/*
* First, if we have any adequately-presorted paths, just stick a
* Unique node on those. Then consider doing an explicit sort of the
* cheapest input path and Unique'ing that.
*
* When we have DISTINCT ON, we must sort by the more rigorous of
* DISTINCT and ORDER BY, else it won't have the desired behavior.
* Also, if we do have to do an explicit sort, we might as well use
* the more rigorous ordering to avoid a second sort later. (Note
* that the parser will have ensured that one clause is a prefix of
* the other.)
*/
List *needed_pathkeys;
if (parse->hasDistinctOn &&
list_length(root->distinct_pathkeys) <
list_length(root->sort_pathkeys))
needed_pathkeys = root->sort_pathkeys;
else
needed_pathkeys = root->distinct_pathkeys;
foreach(lc, input_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
if (pathkeys_contained_in(needed_pathkeys, path->pathkeys))
{
add_path(distinct_rel, (Path *)
create_upper_unique_path(root, distinct_rel,
path,
list_length(root->distinct_pathkeys),
numDistinctRows));
}
}
/* For explicit-sort case, always use the more rigorous clause */
if (list_length(root->distinct_pathkeys) <
list_length(root->sort_pathkeys))
{
needed_pathkeys = root->sort_pathkeys;
/* Assert checks that parser didn't mess up... */
Assert(pathkeys_contained_in(root->distinct_pathkeys,
needed_pathkeys));
}
else
needed_pathkeys = root->distinct_pathkeys;
path = cheapest_input_path;
if (!pathkeys_contained_in(needed_pathkeys, path->pathkeys))
path = (Path *) create_sort_path(root, distinct_rel,
path,
needed_pathkeys,
-1.0);
add_path(distinct_rel, (Path *)
create_upper_unique_path(root, distinct_rel,
path,
list_length(root->distinct_pathkeys),
numDistinctRows));
}
/*
* Consider hash-based implementations of DISTINCT, if possible.
*
* If we were not able to make any other types of path, we *must* hash or
* die trying. If we do have other choices, there are several things that
* should prevent selection of hashing: if the query uses DISTINCT ON
* (because it won't really have the expected behavior if we hash), or if
* enable_hashagg is off, or if it looks like the hashtable will exceed
* work_mem.
*
* Note: grouping_is_hashable() is much more expensive to check than the
* other gating conditions, so we want to do it last.
*/
if (distinct_rel->pathlist == NIL)
allow_hash = true; /* we have no alternatives */
else if (parse->hasDistinctOn || !enable_hashagg)
allow_hash = false; /* policy-based decision not to hash */
else
{
Size hashentrysize;
/* Estimate per-hash-entry space at tuple width... */
hashentrysize = MAXALIGN(cheapest_input_path->pathtarget->width) +
MAXALIGN(SizeofMinimalTupleHeader);
/* plus the per-hash-entry overhead */
hashentrysize += hash_agg_entry_size(0);
/* Allow hashing only if hashtable is predicted to fit in work_mem */
allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L);
}
if (allow_hash && grouping_is_hashable(parse->distinctClause))
{
/* Generate hashed aggregate path --- no sort needed */
add_path(distinct_rel, (Path *)
create_agg_path(root,
distinct_rel,
cheapest_input_path,
cheapest_input_path->pathtarget,
AGG_HASHED,
AGGSPLIT_SIMPLE,
parse->distinctClause,
NIL,
NULL,
numDistinctRows));
}
/* Give a helpful error if we failed to find any implementation */
if (distinct_rel->pathlist == NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not implement DISTINCT"),
errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
/*
* If there is an FDW that's responsible for all baserels of the query,
* let it consider adding ForeignPaths.
*/
if (distinct_rel->fdwroutine &&
distinct_rel->fdwroutine->GetForeignUpperPaths)
distinct_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_DISTINCT,
input_rel, distinct_rel);
/* Let extensions possibly add some more paths */
if (create_upper_paths_hook)
(*create_upper_paths_hook) (root, UPPERREL_DISTINCT,
input_rel, distinct_rel);
/* Now choose the best path(s) */
set_cheapest(distinct_rel);
return distinct_rel;
}
/*
* create_ordered_paths
*
* Build a new upperrel containing Paths for ORDER BY evaluation.
*
* All paths in the result must satisfy the ORDER BY ordering.
* The only new path we need consider is an explicit sort on the
* cheapest-total existing path.
*
* input_rel: contains the source-data Paths
* target: the output tlist the result Paths must emit
* limit_tuples: estimated bound on the number of output tuples,
* or -1 if no LIMIT or couldn't estimate
*/
static RelOptInfo *
create_ordered_paths(PlannerInfo *root,
RelOptInfo *input_rel,
PathTarget *target,
double limit_tuples)
{
Path *cheapest_input_path = input_rel->cheapest_total_path;
RelOptInfo *ordered_rel;
ListCell *lc;
/* For now, do all work in the (ORDERED, NULL) upperrel */
ordered_rel = fetch_upper_rel(root, UPPERREL_ORDERED, NULL);
/*
* If the input relation is not parallel-safe, then the ordered relation
* can't be parallel-safe, either. Otherwise, it's parallel-safe if the
* target list is parallel-safe.
*/
if (input_rel->consider_parallel &&
is_parallel_safe(root, (Node *) target->exprs))
ordered_rel->consider_parallel = true;
/*
* If the input rel belongs to a single FDW, so does the ordered_rel.
*/
ordered_rel->serverid = input_rel->serverid;
ordered_rel->userid = input_rel->userid;
ordered_rel->useridiscurrent = input_rel->useridiscurrent;
ordered_rel->fdwroutine = input_rel->fdwroutine;
foreach(lc, input_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
bool is_sorted;
is_sorted = pathkeys_contained_in(root->sort_pathkeys,
path->pathkeys);
if (path == cheapest_input_path || is_sorted)
{
if (!is_sorted)
{
/* An explicit sort here can take advantage of LIMIT */
path = (Path *) create_sort_path(root,
ordered_rel,
path,
root->sort_pathkeys,
limit_tuples);
}
/* Add projection step if needed */
if (path->pathtarget != target)
path = apply_projection_to_path(root, ordered_rel,
path, target);
add_path(ordered_rel, path);
}
}
/*
* generate_gather_paths() will have already generated a simple Gather
* path for the best parallel path, if any, and the loop above will have
* considered sorting it. Similarly, generate_gather_paths() will also
* have generated order-preserving Gather Merge plans which can be used
* without sorting if they happen to match the sort_pathkeys, and the loop
* above will have handled those as well. However, there's one more
* possibility: it may make sense to sort the cheapest partial path
* according to the required output order and then use Gather Merge.
*/
if (ordered_rel->consider_parallel && root->sort_pathkeys != NIL &&
input_rel->partial_pathlist != NIL)
{
Path *cheapest_partial_path;
cheapest_partial_path = linitial(input_rel->partial_pathlist);
/*
* If cheapest partial path doesn't need a sort, this is redundant
* with what's already been tried.
*/
if (!pathkeys_contained_in(root->sort_pathkeys,
cheapest_partial_path->pathkeys))
{
Path *path;
double total_groups;
path = (Path *) create_sort_path(root,
ordered_rel,
cheapest_partial_path,
root->sort_pathkeys,
limit_tuples);
total_groups = cheapest_partial_path->rows *
cheapest_partial_path->parallel_workers;
path = (Path *)
create_gather_merge_path(root, ordered_rel,
path,
path->pathtarget,
root->sort_pathkeys, NULL,
&total_groups);
/* Add projection step if needed */
if (path->pathtarget != target)
path = apply_projection_to_path(root, ordered_rel,
path, target);
add_path(ordered_rel, path);
}
}
/*
* If there is an FDW that's responsible for all baserels of the query,
* let it consider adding ForeignPaths.
*/
if (ordered_rel->fdwroutine &&
ordered_rel->fdwroutine->GetForeignUpperPaths)
ordered_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_ORDERED,
input_rel, ordered_rel);
/* Let extensions possibly add some more paths */
if (create_upper_paths_hook)
(*create_upper_paths_hook) (root, UPPERREL_ORDERED,
input_rel, ordered_rel);
/*
* No need to bother with set_cheapest here; grouping_planner does not
* need us to do it.
*/
Assert(ordered_rel->pathlist != NIL);
return ordered_rel;
}
/*
* make_group_input_target
* Generate appropriate PathTarget for initial input to grouping nodes.
*
* If there is grouping or aggregation, the scan/join subplan cannot emit
* the query's final targetlist; for example, it certainly can't emit any
* aggregate function calls. This routine generates the correct target
* for the scan/join subplan.
*
* The query target list passed from the parser already contains entries
* for all ORDER BY and GROUP BY expressions, but it will not have entries
* for variables used only in HAVING clauses; so we need to add those
* variables to the subplan target list. Also, we flatten all expressions
* except GROUP BY items into their component variables; other expressions
* will be computed by the upper plan nodes rather than by the subplan.
* For example, given a query like
* SELECT a+b,SUM(c+d) FROM table GROUP BY a+b;
* we want to pass this targetlist to the subplan:
* a+b,c,d
* where the a+b target will be used by the Sort/Group steps, and the
* other targets will be used for computing the final results.
*
* 'final_target' is the query's final target list (in PathTarget form)
*
* The result is the PathTarget to be computed by the Paths returned from
* query_planner().
*/
static PathTarget *
make_group_input_target(PlannerInfo *root, PathTarget *final_target)
{
Query *parse = root->parse;
PathTarget *input_target;
List *non_group_cols;
List *non_group_vars;
int i;
ListCell *lc;
/*
* We must build a target containing all grouping columns, plus any other
* Vars mentioned in the query's targetlist and HAVING qual.
*/
input_target = create_empty_pathtarget();
non_group_cols = NIL;
i = 0;
foreach(lc, final_target->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
Index sgref = get_pathtarget_sortgroupref(final_target, i);
if (sgref && parse->groupClause &&
get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL)
{
/*
* It's a grouping column, so add it to the input target as-is.
*/
add_column_to_pathtarget(input_target, expr, sgref);
}
else
{
/*
* Non-grouping column, so just remember the expression for later
* call to pull_var_clause.
*/
non_group_cols = lappend(non_group_cols, expr);
}
i++;
}
/*
* If there's a HAVING clause, we'll need the Vars it uses, too.
*/
if (parse->havingQual)
non_group_cols = lappend(non_group_cols, parse->havingQual);
/*
* Pull out all the Vars mentioned in non-group cols (plus HAVING), and
* add them to the input target if not already present. (A Var used
* directly as a GROUP BY item will be present already.) Note this
* includes Vars used in resjunk items, so we are covering the needs of
* ORDER BY and window specifications. Vars used within Aggrefs and
* WindowFuncs will be pulled out here, too.
*/
non_group_vars = pull_var_clause((Node *) non_group_cols,
PVC_RECURSE_AGGREGATES |
PVC_RECURSE_WINDOWFUNCS |
PVC_INCLUDE_PLACEHOLDERS);
add_new_columns_to_pathtarget(input_target, non_group_vars);
/* clean up cruft */
list_free(non_group_vars);
list_free(non_group_cols);
/* XXX this causes some redundant cost calculation ... */
return set_pathtarget_cost_width(root, input_target);
}
/*
* make_partial_grouping_target
* Generate appropriate PathTarget for output of partial aggregate
* (or partial grouping, if there are no aggregates) nodes.
*
* A partial aggregation node needs to emit all the same aggregates that
* a regular aggregation node would, plus any aggregates used in HAVING;
* except that the Aggref nodes should be marked as partial aggregates.
*
* In addition, we'd better emit any Vars and PlaceholderVars that are
* used outside of Aggrefs in the aggregation tlist and HAVING. (Presumably,
* these would be Vars that are grouped by or used in grouping expressions.)
*
* grouping_target is the tlist to be emitted by the topmost aggregation step.
* We get the HAVING clause out of *root.
*/
static PathTarget *
make_partial_grouping_target(PlannerInfo *root, PathTarget *grouping_target)
{
Query *parse = root->parse;
PathTarget *partial_target;
List *non_group_cols;
List *non_group_exprs;
int i;
ListCell *lc;
partial_target = create_empty_pathtarget();
non_group_cols = NIL;
i = 0;
foreach(lc, grouping_target->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
Index sgref = get_pathtarget_sortgroupref(grouping_target, i);
if (sgref && parse->groupClause &&
get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL)
{
/*
* It's a grouping column, so add it to the partial_target as-is.
* (This allows the upper agg step to repeat the grouping calcs.)
*/
add_column_to_pathtarget(partial_target, expr, sgref);
}
else
{
/*
* Non-grouping column, so just remember the expression for later
* call to pull_var_clause.
*/
non_group_cols = lappend(non_group_cols, expr);
}
i++;
}
/*
* If there's a HAVING clause, we'll need the Vars/Aggrefs it uses, too.
*/
if (parse->havingQual)
non_group_cols = lappend(non_group_cols, parse->havingQual);
/*
* Pull out all the Vars, PlaceHolderVars, and Aggrefs mentioned in
* non-group cols (plus HAVING), and add them to the partial_target if not
* already present. (An expression used directly as a GROUP BY item will
* be present already.) Note this includes Vars used in resjunk items, so
* we are covering the needs of ORDER BY and window specifications.
*/
non_group_exprs = pull_var_clause((Node *) non_group_cols,
PVC_INCLUDE_AGGREGATES |
PVC_RECURSE_WINDOWFUNCS |
PVC_INCLUDE_PLACEHOLDERS);
add_new_columns_to_pathtarget(partial_target, non_group_exprs);
/*
* Adjust Aggrefs to put them in partial mode. At this point all Aggrefs
* are at the top level of the target list, so we can just scan the list
* rather than recursing through the expression trees.
*/
foreach(lc, partial_target->exprs)
{
Aggref *aggref = (Aggref *) lfirst(lc);
if (IsA(aggref, Aggref))
{
Aggref *newaggref;
/*
* We shouldn't need to copy the substructure of the Aggref node,
* but flat-copy the node itself to avoid damaging other trees.
*/
newaggref = makeNode(Aggref);
memcpy(newaggref, aggref, sizeof(Aggref));
/* For now, assume serialization is required */
mark_partial_aggref(newaggref, AGGSPLIT_INITIAL_SERIAL);
lfirst(lc) = newaggref;
}
}
/* clean up cruft */
list_free(non_group_exprs);
list_free(non_group_cols);
/* XXX this causes some redundant cost calculation ... */
return set_pathtarget_cost_width(root, partial_target);
}
/*
* mark_partial_aggref
* Adjust an Aggref to make it represent a partial-aggregation step.
*
* The Aggref node is modified in-place; caller must do any copying required.
*/
void
mark_partial_aggref(Aggref *agg, AggSplit aggsplit)
{
/* aggtranstype should be computed by this point */
Assert(OidIsValid(agg->aggtranstype));
/* ... but aggsplit should still be as the parser left it */
Assert(agg->aggsplit == AGGSPLIT_SIMPLE);
/* Mark the Aggref with the intended partial-aggregation mode */
agg->aggsplit = aggsplit;
/*
* Adjust result type if needed. Normally, a partial aggregate returns
* the aggregate's transition type; but if that's INTERNAL and we're
* serializing, it returns BYTEA instead.
*/
if (DO_AGGSPLIT_SKIPFINAL(aggsplit))
{
if (agg->aggtranstype == INTERNALOID && DO_AGGSPLIT_SERIALIZE(aggsplit))
agg->aggtype = BYTEAOID;
else
agg->aggtype = agg->aggtranstype;
}
}
/*
* postprocess_setop_tlist
* Fix up targetlist returned by plan_set_operations().
*
* We need to transpose sort key info from the orig_tlist into new_tlist.
* NOTE: this would not be good enough if we supported resjunk sort keys
* for results of set operations --- then, we'd need to project a whole
* new tlist to evaluate the resjunk columns. For now, just ereport if we
* find any resjunk columns in orig_tlist.
*/
static List *
postprocess_setop_tlist(List *new_tlist, List *orig_tlist)
{
ListCell *l;
ListCell *orig_tlist_item = list_head(orig_tlist);
foreach(l, new_tlist)
{
TargetEntry *new_tle = lfirst_node(TargetEntry, l);
TargetEntry *orig_tle;
/* ignore resjunk columns in setop result */
if (new_tle->resjunk)
continue;
Assert(orig_tlist_item != NULL);
orig_tle = lfirst_node(TargetEntry, orig_tlist_item);
orig_tlist_item = lnext(orig_tlist_item);
if (orig_tle->resjunk) /* should not happen */
elog(ERROR, "resjunk output columns are not implemented");
Assert(new_tle->resno == orig_tle->resno);
new_tle->ressortgroupref = orig_tle->ressortgroupref;
}
if (orig_tlist_item != NULL)
elog(ERROR, "resjunk output columns are not implemented");
return new_tlist;
}
/*
* select_active_windows
* Create a list of the "active" window clauses (ie, those referenced
* by non-deleted WindowFuncs) in the order they are to be executed.
*/
static List *
select_active_windows(PlannerInfo *root, WindowFuncLists *wflists)
{
List *result;
List *actives;
ListCell *lc;
/* First, make a list of the active windows */
actives = NIL;
foreach(lc, root->parse->windowClause)
{
WindowClause *wc = lfirst_node(WindowClause, lc);
/* It's only active if wflists shows some related WindowFuncs */
Assert(wc->winref <= wflists->maxWinRef);
if (wflists->windowFuncs[wc->winref] != NIL)
actives = lappend(actives, wc);
}
/*
* Now, ensure that windows with identical partitioning/ordering clauses
* are adjacent in the list. This is required by the SQL standard, which
* says that only one sort is to be used for such windows, even if they
* are otherwise distinct (eg, different names or framing clauses).
*
* There is room to be much smarter here, for example detecting whether
* one window's sort keys are a prefix of another's (so that sorting for
* the latter would do for the former), or putting windows first that
* match a sort order available for the underlying query. For the moment
* we are content with meeting the spec.
*/
result = NIL;
while (actives != NIL)
{
WindowClause *wc = linitial_node(WindowClause, actives);
ListCell *prev;
ListCell *next;
/* Move wc from actives to result */
actives = list_delete_first(actives);
result = lappend(result, wc);
/* Now move any matching windows from actives to result */
prev = NULL;
for (lc = list_head(actives); lc; lc = next)
{
WindowClause *wc2 = lfirst_node(WindowClause, lc);
next = lnext(lc);
/* framing options are NOT to be compared here! */
if (equal(wc->partitionClause, wc2->partitionClause) &&
equal(wc->orderClause, wc2->orderClause))
{
actives = list_delete_cell(actives, lc, prev);
result = lappend(result, wc2);
}
else
prev = lc;
}
}
return result;
}
/*
* make_window_input_target
* Generate appropriate PathTarget for initial input to WindowAgg nodes.
*
* When the query has window functions, this function computes the desired
* target to be computed by the node just below the first WindowAgg.
* This tlist must contain all values needed to evaluate the window functions,
* compute the final target list, and perform any required final sort step.
* If multiple WindowAggs are needed, each intermediate one adds its window
* function results onto this base tlist; only the topmost WindowAgg computes
* the actual desired target list.
*
* This function is much like make_group_input_target, though not quite enough
* like it to share code. As in that function, we flatten most expressions
* into their component variables. But we do not want to flatten window
* PARTITION BY/ORDER BY clauses, since that might result in multiple
* evaluations of them, which would be bad (possibly even resulting in
* inconsistent answers, if they contain volatile functions).
* Also, we must not flatten GROUP BY clauses that were left unflattened by
* make_group_input_target, because we may no longer have access to the
* individual Vars in them.
*
* Another key difference from make_group_input_target is that we don't
* flatten Aggref expressions, since those are to be computed below the
* window functions and just referenced like Vars above that.
*
* 'final_target' is the query's final target list (in PathTarget form)
* 'activeWindows' is the list of active windows previously identified by
* select_active_windows.
*
* The result is the PathTarget to be computed by the plan node immediately
* below the first WindowAgg node.
*/
static PathTarget *
make_window_input_target(PlannerInfo *root,
PathTarget *final_target,
List *activeWindows)
{
Query *parse = root->parse;
PathTarget *input_target;
Bitmapset *sgrefs;
List *flattenable_cols;
List *flattenable_vars;
int i;
ListCell *lc;
Assert(parse->hasWindowFuncs);
/*
* Collect the sortgroupref numbers of window PARTITION/ORDER BY clauses
* into a bitmapset for convenient reference below.
*/
sgrefs = NULL;
foreach(lc, activeWindows)
{
WindowClause *wc = lfirst_node(WindowClause, lc);
ListCell *lc2;
foreach(lc2, wc->partitionClause)
{
SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2);
sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
}
foreach(lc2, wc->orderClause)
{
SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2);
sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
}
}
/* Add in sortgroupref numbers of GROUP BY clauses, too */
foreach(lc, parse->groupClause)
{
SortGroupClause *grpcl = lfirst_node(SortGroupClause, lc);
sgrefs = bms_add_member(sgrefs, grpcl->tleSortGroupRef);
}
/*
* Construct a target containing all the non-flattenable targetlist items,
* and save aside the others for a moment.
*/
input_target = create_empty_pathtarget();
flattenable_cols = NIL;
i = 0;
foreach(lc, final_target->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
Index sgref = get_pathtarget_sortgroupref(final_target, i);
/*
* Don't want to deconstruct window clauses or GROUP BY items. (Note
* that such items can't contain window functions, so it's okay to
* compute them below the WindowAgg nodes.)
*/
if (sgref != 0 && bms_is_member(sgref, sgrefs))
{
/*
* Don't want to deconstruct this value, so add it to the input
* target as-is.
*/
add_column_to_pathtarget(input_target, expr, sgref);
}
else
{
/*
* Column is to be flattened, so just remember the expression for
* later call to pull_var_clause.
*/
flattenable_cols = lappend(flattenable_cols, expr);
}
i++;
}
/*
* Pull out all the Vars and Aggrefs mentioned in flattenable columns, and
* add them to the input target if not already present. (Some might be
* there already because they're used directly as window/group clauses.)
*
* Note: it's essential to use PVC_INCLUDE_AGGREGATES here, so that any
* Aggrefs are placed in the Agg node's tlist and not left to be computed
* at higher levels. On the other hand, we should recurse into
* WindowFuncs to make sure their input expressions are available.
*/
flattenable_vars = pull_var_clause((Node *) flattenable_cols,
PVC_INCLUDE_AGGREGATES |
PVC_RECURSE_WINDOWFUNCS |
PVC_INCLUDE_PLACEHOLDERS);
add_new_columns_to_pathtarget(input_target, flattenable_vars);
/* clean up cruft */
list_free(flattenable_vars);
list_free(flattenable_cols);
/* XXX this causes some redundant cost calculation ... */
return set_pathtarget_cost_width(root, input_target);
}
/*
* make_pathkeys_for_window
* Create a pathkeys list describing the required input ordering
* for the given WindowClause.
*
* The required ordering is first the PARTITION keys, then the ORDER keys.
* In the future we might try to implement windowing using hashing, in which
* case the ordering could be relaxed, but for now we always sort.
*
* Caution: if you change this, see createplan.c's get_column_info_for_window!
*/
static List *
make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
List *tlist)
{
List *window_pathkeys;
List *window_sortclauses;
/* Throw error if can't sort */
if (!grouping_is_sortable(wc->partitionClause))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not implement window PARTITION BY"),
errdetail("Window partitioning columns must be of sortable datatypes.")));
if (!grouping_is_sortable(wc->orderClause))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not implement window ORDER BY"),
errdetail("Window ordering columns must be of sortable datatypes.")));
/* Okay, make the combined pathkeys */
window_sortclauses = list_concat(list_copy(wc->partitionClause),
list_copy(wc->orderClause));
window_pathkeys = make_pathkeys_for_sortclauses(root,
window_sortclauses,
tlist);
list_free(window_sortclauses);
return window_pathkeys;
}
/*
* make_sort_input_target
* Generate appropriate PathTarget for initial input to Sort step.
*
* If the query has ORDER BY, this function chooses the target to be computed
* by the node just below the Sort (and DISTINCT, if any, since Unique can't
* project) steps. This might or might not be identical to the query's final
* output target.
*
* The main argument for keeping the sort-input tlist the same as the final
* is that we avoid a separate projection node (which will be needed if
* they're different, because Sort can't project). However, there are also
* advantages to postponing tlist evaluation till after the Sort: it ensures
* a consistent order of evaluation for any volatile functions in the tlist,
* and if there's also a LIMIT, we can stop the query without ever computing
* tlist functions for later rows, which is beneficial for both volatile and
* expensive functions.
*
* Our current policy is to postpone volatile expressions till after the sort
* unconditionally (assuming that that's possible, ie they are in plain tlist
* columns and not ORDER BY/GROUP BY/DISTINCT columns). We also prefer to
* postpone set-returning expressions, because running them beforehand would
* bloat the sort dataset, and because it might cause unexpected output order
* if the sort isn't stable. However there's a constraint on that: all SRFs
* in the tlist should be evaluated at the same plan step, so that they can
* run in sync in nodeProjectSet. So if any SRFs are in sort columns, we
* mustn't postpone any SRFs. (Note that in principle that policy should
* probably get applied to the group/window input targetlists too, but we
* have not done that historically.) Lastly, expensive expressions are
* postponed if there is a LIMIT, or if root->tuple_fraction shows that
* partial evaluation of the query is possible (if neither is true, we expect
* to have to evaluate the expressions for every row anyway), or if there are
* any volatile or set-returning expressions (since once we've put in a
* projection at all, it won't cost any more to postpone more stuff).
*
* Another issue that could potentially be considered here is that
* evaluating tlist expressions could result in data that's either wider
* or narrower than the input Vars, thus changing the volume of data that
* has to go through the Sort. However, we usually have only a very bad
* idea of the output width of any expression more complex than a Var,
* so for now it seems too risky to try to optimize on that basis.
*
* Note that if we do produce a modified sort-input target, and then the
* query ends up not using an explicit Sort, no particular harm is done:
* we'll initially use the modified target for the preceding path nodes,
* but then change them to the final target with apply_projection_to_path.
* Moreover, in such a case the guarantees about evaluation order of
* volatile functions still hold, since the rows are sorted already.
*
* This function has some things in common with make_group_input_target and
* make_window_input_target, though the detailed rules for what to do are
* different. We never flatten/postpone any grouping or ordering columns;
* those are needed before the sort. If we do flatten a particular
* expression, we leave Aggref and WindowFunc nodes alone, since those were
* computed earlier.
*
* 'final_target' is the query's final target list (in PathTarget form)
* 'have_postponed_srfs' is an output argument, see below
*
* The result is the PathTarget to be computed by the plan node immediately
* below the Sort step (and the Distinct step, if any). This will be
* exactly final_target if we decide a projection step wouldn't be helpful.
*
* In addition, *have_postponed_srfs is set to true if we choose to postpone
* any set-returning functions to after the Sort.
*/
static PathTarget *
make_sort_input_target(PlannerInfo *root,
PathTarget *final_target,
bool *have_postponed_srfs)
{
Query *parse = root->parse;
PathTarget *input_target;
int ncols;
bool *col_is_srf;
bool *postpone_col;
bool have_srf;
bool have_volatile;
bool have_expensive;
bool have_srf_sortcols;
bool postpone_srfs;
List *postponable_cols;
List *postponable_vars;
int i;
ListCell *lc;
/* Shouldn't get here unless query has ORDER BY */
Assert(parse->sortClause);
*have_postponed_srfs = false; /* default result */
/* Inspect tlist and collect per-column information */
ncols = list_length(final_target->exprs);
col_is_srf = (bool *) palloc0(ncols * sizeof(bool));
postpone_col = (bool *) palloc0(ncols * sizeof(bool));
have_srf = have_volatile = have_expensive = have_srf_sortcols = false;
i = 0;
foreach(lc, final_target->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
/*
* If the column has a sortgroupref, assume it has to be evaluated
* before sorting. Generally such columns would be ORDER BY, GROUP
* BY, etc targets. One exception is columns that were removed from
* GROUP BY by remove_useless_groupby_columns() ... but those would
* only be Vars anyway. There don't seem to be any cases where it
* would be worth the trouble to double-check.
*/
if (get_pathtarget_sortgroupref(final_target, i) == 0)
{
/*
* Check for SRF or volatile functions. Check the SRF case first
* because we must know whether we have any postponed SRFs.
*/
if (parse->hasTargetSRFs &&
expression_returns_set((Node *) expr))
{
/* We'll decide below whether these are postponable */
col_is_srf[i] = true;
have_srf = true;
}
else if (contain_volatile_functions((Node *) expr))
{
/* Unconditionally postpone */
postpone_col[i] = true;
have_volatile = true;
}
else
{
/*
* Else check the cost. XXX it's annoying to have to do this
* when set_pathtarget_cost_width() just did it. Refactor to
* allow sharing the work?
*/
QualCost cost;
cost_qual_eval_node(&cost, (Node *) expr, root);
/*
* We arbitrarily define "expensive" as "more than 10X
* cpu_operator_cost". Note this will take in any PL function
* with default cost.
*/
if (cost.per_tuple > 10 * cpu_operator_cost)
{
postpone_col[i] = true;
have_expensive = true;
}
}
}
else
{
/* For sortgroupref cols, just check if any contain SRFs */
if (!have_srf_sortcols &&
parse->hasTargetSRFs &&
expression_returns_set((Node *) expr))
have_srf_sortcols = true;
}
i++;
}
/*
* We can postpone SRFs if we have some but none are in sortgroupref cols.
*/
postpone_srfs = (have_srf && !have_srf_sortcols);
/*
* If we don't need a post-sort projection, just return final_target.
*/
if (!(postpone_srfs || have_volatile ||
(have_expensive &&
(parse->limitCount || root->tuple_fraction > 0))))
return final_target;
/*
* Report whether the post-sort projection will contain set-returning
* functions. This is important because it affects whether the Sort can
* rely on the query's LIMIT (if any) to bound the number of rows it needs
* to return.
*/
*have_postponed_srfs = postpone_srfs;
/*
* Construct the sort-input target, taking all non-postponable columns and
* then adding Vars, PlaceHolderVars, Aggrefs, and WindowFuncs found in
* the postponable ones.
*/
input_target = create_empty_pathtarget();
postponable_cols = NIL;
i = 0;
foreach(lc, final_target->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
if (postpone_col[i] || (postpone_srfs && col_is_srf[i]))
postponable_cols = lappend(postponable_cols, expr);
else
add_column_to_pathtarget(input_target, expr,
get_pathtarget_sortgroupref(final_target, i));
i++;
}
/*
* Pull out all the Vars, Aggrefs, and WindowFuncs mentioned in
* postponable columns, and add them to the sort-input target if not
* already present. (Some might be there already.) We mustn't
* deconstruct Aggrefs or WindowFuncs here, since the projection node
* would be unable to recompute them.
*/
postponable_vars = pull_var_clause((Node *) postponable_cols,
PVC_INCLUDE_AGGREGATES |
PVC_INCLUDE_WINDOWFUNCS |
PVC_INCLUDE_PLACEHOLDERS);
add_new_columns_to_pathtarget(input_target, postponable_vars);
/* clean up cruft */
list_free(postponable_vars);
list_free(postponable_cols);
/* XXX this represents even more redundant cost calculation ... */
return set_pathtarget_cost_width(root, input_target);
}
/*
* get_cheapest_fractional_path
* Find the cheapest path for retrieving a specified fraction of all
* the tuples expected to be returned by the given relation.
*
* We interpret tuple_fraction the same way as grouping_planner.
*
* We assume set_cheapest() has been run on the given rel.
*/
Path *
get_cheapest_fractional_path(RelOptInfo *rel, double tuple_fraction)
{
Path *best_path = rel->cheapest_total_path;
ListCell *l;
/* If all tuples will be retrieved, just return the cheapest-total path */
if (tuple_fraction <= 0.0)
return best_path;
/* Convert absolute # of tuples to a fraction; no need to clamp to 0..1 */
if (tuple_fraction >= 1.0 && best_path->rows > 0)
tuple_fraction /= best_path->rows;
foreach(l, rel->pathlist)
{
Path *path = (Path *) lfirst(l);
if (path == rel->cheapest_total_path ||
compare_fractional_path_costs(best_path, path, tuple_fraction) <= 0)
continue;
best_path = path;
}
return best_path;
}
/*
* adjust_paths_for_srfs
* Fix up the Paths of the given upperrel to handle tSRFs properly.
*
* The executor can only handle set-returning functions that appear at the
* top level of the targetlist of a ProjectSet plan node. If we have any SRFs
* that are not at top level, we need to split up the evaluation into multiple
* plan levels in which each level satisfies this constraint. This function
* modifies each Path of an upperrel that (might) compute any SRFs in its
* output tlist to insert appropriate projection steps.
*
* The given targets and targets_contain_srfs lists are from
* split_pathtarget_at_srfs(). We assume the existing Paths emit the first
* target in targets.
*/
static void
adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel,
List *targets, List *targets_contain_srfs)
{
ListCell *lc;
Assert(list_length(targets) == list_length(targets_contain_srfs));
Assert(!linitial_int(targets_contain_srfs));
/* If no SRFs appear at this plan level, nothing to do */
if (list_length(targets) == 1)
return;
/*
* Stack SRF-evaluation nodes atop each path for the rel.
*
* In principle we should re-run set_cheapest() here to identify the
* cheapest path, but it seems unlikely that adding the same tlist eval
* costs to all the paths would change that, so we don't bother. Instead,
* just assume that the cheapest-startup and cheapest-total paths remain
* so. (There should be no parameterized paths anymore, so we needn't
* worry about updating cheapest_parameterized_paths.)
*/
foreach(lc, rel->pathlist)
{
Path *subpath = (Path *) lfirst(lc);
Path *newpath = subpath;
ListCell *lc1,
*lc2;
Assert(subpath->param_info == NULL);
forboth(lc1, targets, lc2, targets_contain_srfs)
{
PathTarget *thistarget = lfirst_node(PathTarget, lc1);
bool contains_srfs = (bool) lfirst_int(lc2);
/* If this level doesn't contain SRFs, do regular projection */
if (contains_srfs)
newpath = (Path *) create_set_projection_path(root,
rel,
newpath,
thistarget);
else
newpath = (Path *) apply_projection_to_path(root,
rel,
newpath,
thistarget);
}
lfirst(lc) = newpath;
if (subpath == rel->cheapest_startup_path)
rel->cheapest_startup_path = newpath;
if (subpath == rel->cheapest_total_path)
rel->cheapest_total_path = newpath;
}
/* Likewise for partial paths, if any */
foreach(lc, rel->partial_pathlist)
{
Path *subpath = (Path *) lfirst(lc);
Path *newpath = subpath;
ListCell *lc1,
*lc2;
Assert(subpath->param_info == NULL);
forboth(lc1, targets, lc2, targets_contain_srfs)
{
PathTarget *thistarget = lfirst_node(PathTarget, lc1);
bool contains_srfs = (bool) lfirst_int(lc2);
/* If this level doesn't contain SRFs, do regular projection */
if (contains_srfs)
newpath = (Path *) create_set_projection_path(root,
rel,
newpath,
thistarget);
else
{
/* avoid apply_projection_to_path, in case of multiple refs */
newpath = (Path *) create_projection_path(root,
rel,
newpath,
thistarget);
}
}
lfirst(lc) = newpath;
}
}
/*
* expression_planner
* Perform planner's transformations on a standalone expression.
*
* Various utility commands need to evaluate expressions that are not part
* of a plannable query. They can do so using the executor's regular
* expression-execution machinery, but first the expression has to be fed
* through here to transform it from parser output to something executable.
*
* Currently, we disallow sublinks in standalone expressions, so there's no
* real "planning" involved here. (That might not always be true though.)
* What we must do is run eval_const_expressions to ensure that any function
* calls are converted to positional notation and function default arguments
* get inserted. The fact that constant subexpressions get simplified is a
* side-effect that is useful when the expression will get evaluated more than
* once. Also, we must fix operator function IDs.
*
* Note: this must not make any damaging changes to the passed-in expression
* tree. (It would actually be okay to apply fix_opfuncids to it, but since
* we first do an expression_tree_mutator-based walk, what is returned will
* be a new node tree.)
*/
Expr *
expression_planner(Expr *expr)
{
Node *result;
/*
* Convert named-argument function calls, insert default arguments and
* simplify constant subexprs
*/
result = eval_const_expressions(NULL, (Node *) expr);
/* Fill in opfuncid values if missing */
fix_opfuncids(result);
return (Expr *) result;
}
/*
* plan_cluster_use_sort
* Use the planner to decide how CLUSTER should implement sorting
*
* tableOid is the OID of a table to be clustered on its index indexOid
* (which is already known to be a btree index). Decide whether it's
* cheaper to do an indexscan or a seqscan-plus-sort to execute the CLUSTER.
* Return true to use sorting, false to use an indexscan.
*
* Note: caller had better already hold some type of lock on the table.
*/
bool
plan_cluster_use_sort(Oid tableOid, Oid indexOid)
{
PlannerInfo *root;
Query *query;
PlannerGlobal *glob;
RangeTblEntry *rte;
RelOptInfo *rel;
IndexOptInfo *indexInfo;
QualCost indexExprCost;
Cost comparisonCost;
Path *seqScanPath;
Path seqScanAndSortPath;
IndexPath *indexScanPath;
ListCell *lc;
/* We can short-circuit the cost comparison if indexscans are disabled */
if (!enable_indexscan)
return true; /* use sort */
/* Set up mostly-dummy planner state */
query = makeNode(Query);
query->commandType = CMD_SELECT;
glob = makeNode(PlannerGlobal);
root = makeNode(PlannerInfo);
root->parse = query;
root->glob = glob;
root->query_level = 1;
root->planner_cxt = CurrentMemoryContext;
root->wt_param_id = -1;
/* Build a minimal RTE for the rel */
rte = makeNode(RangeTblEntry);
rte->rtekind = RTE_RELATION;
rte->relid = tableOid;
rte->relkind = RELKIND_RELATION; /* Don't be too picky. */
rte->lateral = false;
rte->inh = false;
rte->inFromCl = true;
query->rtable = list_make1(rte);
/* Set up RTE/RelOptInfo arrays */
setup_simple_rel_arrays(root);
/* Build RelOptInfo */
rel = build_simple_rel(root, 1, NULL);
/* Locate IndexOptInfo for the target index */
indexInfo = NULL;
foreach(lc, rel->indexlist)
{
indexInfo = lfirst_node(IndexOptInfo, lc);
if (indexInfo->indexoid == indexOid)
break;
}
/*
* It's possible that get_relation_info did not generate an IndexOptInfo
* for the desired index; this could happen if it's not yet reached its
* indcheckxmin usability horizon, or if it's a system index and we're
* ignoring system indexes. In such cases we should tell CLUSTER to not
* trust the index contents but use seqscan-and-sort.
*/
if (lc == NULL) /* not in the list? */
return true; /* use sort */
/*
* Rather than doing all the pushups that would be needed to use
* set_baserel_size_estimates, just do a quick hack for rows and width.
*/
rel->rows = rel->tuples;
rel->reltarget->width = get_relation_data_width(tableOid, NULL);
root->total_table_pages = rel->pages;
/*
* Determine eval cost of the index expressions, if any. We need to
* charge twice that amount for each tuple comparison that happens during
* the sort, since tuplesort.c will have to re-evaluate the index
* expressions each time. (XXX that's pretty inefficient...)
*/
cost_qual_eval(&indexExprCost, indexInfo->indexprs, root);
comparisonCost = 2.0 * (indexExprCost.startup + indexExprCost.per_tuple);
/* Estimate the cost of seq scan + sort */
seqScanPath = create_seqscan_path(root, rel, NULL, 0);
cost_sort(&seqScanAndSortPath, root, NIL,
seqScanPath->total_cost, rel->tuples, rel->reltarget->width,
comparisonCost, maintenance_work_mem, -1.0);
/* Estimate the cost of index scan */
indexScanPath = create_index_path(root, indexInfo,
NIL, NIL, NIL, NIL, NIL,
ForwardScanDirection, false,
NULL, 1.0, false);
return (seqScanAndSortPath.total_cost < indexScanPath->path.total_cost);
}
/*
* plan_create_index_workers
* Use the planner to decide how many parallel worker processes
* CREATE INDEX should request for use
*
* tableOid is the table on which the index is to be built. indexOid is the
* OID of an index to be created or reindexed (which must be a btree index).
*
* Return value is the number of parallel worker processes to request. It
* may be unsafe to proceed if this is 0. Note that this does not include the
* leader participating as a worker (value is always a number of parallel
* worker processes).
*
* Note: caller had better already hold some type of lock on the table and
* index.
*/
int
plan_create_index_workers(Oid tableOid, Oid indexOid)
{
PlannerInfo *root;
Query *query;
PlannerGlobal *glob;
RangeTblEntry *rte;
Relation heap;
Relation index;
RelOptInfo *rel;
int parallel_workers;
BlockNumber heap_blocks;
double reltuples;
double allvisfrac;
/* Return immediately when parallelism disabled */
if (max_parallel_maintenance_workers == 0)
return 0;
/* Set up largely-dummy planner state */
query = makeNode(Query);
query->commandType = CMD_SELECT;
glob = makeNode(PlannerGlobal);
root = makeNode(PlannerInfo);
root->parse = query;
root->glob = glob;
root->query_level = 1;
root->planner_cxt = CurrentMemoryContext;
root->wt_param_id = -1;
/*
* Build a minimal RTE.
*
* Set the target's table to be an inheritance parent. This is a kludge
* that prevents problems within get_relation_info(), which does not
* expect that any IndexOptInfo is currently undergoing REINDEX.
*/
rte = makeNode(RangeTblEntry);
rte->rtekind = RTE_RELATION;
rte->relid = tableOid;
rte->relkind = RELKIND_RELATION; /* Don't be too picky. */
rte->lateral = false;
rte->inh = true;
rte->inFromCl = true;
query->rtable = list_make1(rte);
/* Set up RTE/RelOptInfo arrays */
setup_simple_rel_arrays(root);
/* Build RelOptInfo */
rel = build_simple_rel(root, 1, NULL);
heap = heap_open(tableOid, NoLock);
index = index_open(indexOid, NoLock);
/*
* Determine if it's safe to proceed.
*
* Currently, parallel workers can't access the leader's temporary tables.
* Furthermore, any index predicate or index expressions must be parallel
* safe.
*/
if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
{
parallel_workers = 0;
goto done;
}
/*
* If parallel_workers storage parameter is set for the table, accept that
* as the number of parallel worker processes to launch (though still cap
* at max_parallel_maintenance_workers). Note that we deliberately do not
* consider any other factor when parallel_workers is set. (e.g., memory
* use by workers.)
*/
if (rel->rel_parallel_workers != -1)
{
parallel_workers = Min(rel->rel_parallel_workers,
max_parallel_maintenance_workers);
goto done;
}
/*
* Estimate heap relation size ourselves, since rel->pages cannot be
* trusted (heap RTE was marked as inheritance parent)
*/
estimate_rel_size(heap, NULL, &heap_blocks, &reltuples, &allvisfrac);
/*
* Determine number of workers to scan the heap relation using generic
* model
*/
parallel_workers = compute_parallel_worker(rel, heap_blocks, -1,
max_parallel_maintenance_workers);
/*
* Cap workers based on available maintenance_work_mem as needed.
*
* Note that each tuplesort participant receives an even share of the
* total maintenance_work_mem budget. Aim to leave participants
* (including the leader as a participant) with no less than 32MB of
* memory. This leaves cases where maintenance_work_mem is set to 64MB
* immediately past the threshold of being capable of launching a single
* parallel worker to sort.
*/
while (parallel_workers > 0 &&
maintenance_work_mem / (parallel_workers + 1) < 32768L)
parallel_workers--;
done:
index_close(index, NoLock);
heap_close(heap, NoLock);
return parallel_workers;
}
/*
* get_partitioned_child_rels
* Returns a list of the RT indexes of the partitioned child relations
* with rti as the root parent RT index. Also sets
* *part_cols_updated to true if any of the root rte's updated
* columns is used in the partition key either of the relation whose RTI
* is specified or of any child relation.
*
* Note: This function might get called even for range table entries that
* are not partitioned tables; in such a case, it will simply return NIL.
*/
List *
get_partitioned_child_rels(PlannerInfo *root, Index rti,
bool *part_cols_updated)
{
List *result = NIL;
ListCell *l;
if (part_cols_updated)
*part_cols_updated = false;
foreach(l, root->pcinfo_list)
{
PartitionedChildRelInfo *pc = lfirst_node(PartitionedChildRelInfo, l);
if (pc->parent_relid == rti)
{
result = pc->child_rels;
if (part_cols_updated)
*part_cols_updated = pc->part_cols_updated;
break;
}
}
return result;
}
/*
* get_partitioned_child_rels_for_join
* Build and return a list containing the RTI of every partitioned
* relation which is a child of some rel included in the join.
*/
List *
get_partitioned_child_rels_for_join(PlannerInfo *root, Relids join_relids)
{
List *result = NIL;
ListCell *l;
foreach(l, root->pcinfo_list)
{
PartitionedChildRelInfo *pc = lfirst(l);
if (bms_is_member(pc->parent_relid, join_relids))
result = list_concat(result, list_copy(pc->child_rels));
}
return result;
}
/*
* add_paths_to_grouping_rel
*
* Add non-partial paths to grouping relation.
*/
static void
add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *grouped_rel, PathTarget *target,
PathTarget *partial_grouping_target,
const AggClauseCosts *agg_costs,
const AggClauseCosts *agg_final_costs,
grouping_sets_data *gd, bool can_sort, bool can_hash,
double dNumGroups, List *havingQual)
{
Query *parse = root->parse;
Path *cheapest_path = input_rel->cheapest_total_path;
ListCell *lc;
if (can_sort)
{
/*
* Use any available suitably-sorted path as input, and also consider
* sorting the cheapest-total path.
*/
foreach(lc, input_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
bool is_sorted;
is_sorted = pathkeys_contained_in(root->group_pathkeys,
path->pathkeys);
if (path == cheapest_path || is_sorted)
{
/* Sort the cheapest-total path if it isn't already sorted */
if (!is_sorted)
path = (Path *) create_sort_path(root,
grouped_rel,
path,
root->group_pathkeys,
-1.0);
/* Now decide what to stick atop it */
if (parse->groupingSets)
{
consider_groupingsets_paths(root, grouped_rel,
path, true, can_hash, target,
gd, agg_costs, dNumGroups);
}
else if (parse->hasAggs)
{
/*
* We have aggregation, possibly with plain GROUP BY. Make
* an AggPath.
*/
add_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
path,
target,
parse->groupClause ? AGG_SORTED : AGG_PLAIN,
AGGSPLIT_SIMPLE,
parse->groupClause,
havingQual,
agg_costs,
dNumGroups));
}
else if (parse->groupClause)
{
/*
* We have GROUP BY without aggregation or grouping sets.
* Make a GroupPath.
*/
add_path(grouped_rel, (Path *)
create_group_path(root,
grouped_rel,
path,
target,
parse->groupClause,
havingQual,
dNumGroups));
}
else
{
/* Other cases should have been handled above */
Assert(false);
}
}
}
/*
* Now generate a complete GroupAgg Path atop of the cheapest partial
* path. We can do this using either Gather or Gather Merge.
*/
if (grouped_rel->partial_pathlist)
{
Path *path = (Path *) linitial(grouped_rel->partial_pathlist);
double total_groups = path->rows * path->parallel_workers;
path = (Path *) create_gather_path(root,
grouped_rel,
path,
partial_grouping_target,
NULL,
&total_groups);
/*
* Since Gather's output is always unsorted, we'll need to sort,
* unless there's no GROUP BY clause or a degenerate (constant)
* one, in which case there will only be a single group.
*/
if (root->group_pathkeys)
path = (Path *) create_sort_path(root,
grouped_rel,
path,
root->group_pathkeys,
-1.0);
if (parse->hasAggs)
add_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
path,
target,
parse->groupClause ? AGG_SORTED : AGG_PLAIN,
AGGSPLIT_FINAL_DESERIAL,
parse->groupClause,
havingQual,
agg_final_costs,
dNumGroups));
else
add_path(grouped_rel, (Path *)
create_group_path(root,
grouped_rel,
path,
target,
parse->groupClause,
havingQual,
dNumGroups));
/*
* The point of using Gather Merge rather than Gather is that it
* can preserve the ordering of the input path, so there's no
* reason to try it unless (1) it's possible to produce more than
* one output row and (2) we want the output path to be ordered.
*/
if (parse->groupClause != NIL && root->group_pathkeys != NIL)
{
foreach(lc, grouped_rel->partial_pathlist)
{
Path *subpath = (Path *) lfirst(lc);
Path *gmpath;
double total_groups;
/*
* It's useful to consider paths that are already properly
* ordered for Gather Merge, because those don't need a
* sort. It's also useful to consider the cheapest path,
* because sorting it in parallel and then doing Gather
* Merge may be better than doing an unordered Gather
* followed by a sort. But there's no point in considering
* non-cheapest paths that aren't already sorted
* correctly.
*/
if (path != subpath &&
!pathkeys_contained_in(root->group_pathkeys,
subpath->pathkeys))
continue;
total_groups = subpath->rows * subpath->parallel_workers;
gmpath = (Path *)
create_gather_merge_path(root,
grouped_rel,
subpath,
partial_grouping_target,
root->group_pathkeys,
NULL,
&total_groups);
if (parse->hasAggs)
add_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
gmpath,
target,
parse->groupClause ? AGG_SORTED : AGG_PLAIN,
AGGSPLIT_FINAL_DESERIAL,
parse->groupClause,
havingQual,
agg_final_costs,
dNumGroups));
else
add_path(grouped_rel, (Path *)
create_group_path(root,
grouped_rel,
gmpath,
target,
parse->groupClause,
havingQual,
dNumGroups));
}
}
}
}
if (can_hash)
{
Size hashaggtablesize;
if (parse->groupingSets)
{
/*
* Try for a hash-only groupingsets path over unsorted input.
*/
consider_groupingsets_paths(root, grouped_rel,
cheapest_path, false, true, target,
gd, agg_costs, dNumGroups);
}
else
{
hashaggtablesize = estimate_hashagg_tablesize(cheapest_path,
agg_costs,
dNumGroups);
/*
* Provided that the estimated size of the hashtable does not
* exceed work_mem, we'll generate a HashAgg Path, although if we
* were unable to sort above, then we'd better generate a Path, so
* that we at least have one.
*/
if (hashaggtablesize < work_mem * 1024L ||
grouped_rel->pathlist == NIL)
{
/*
* We just need an Agg over the cheapest-total input path,
* since input order won't matter.
*/
add_path(grouped_rel, (Path *)
create_agg_path(root, grouped_rel,
cheapest_path,
target,
AGG_HASHED,
AGGSPLIT_SIMPLE,
parse->groupClause,
havingQual,
agg_costs,
dNumGroups));
}
}
/*
* Generate a HashAgg Path atop of the cheapest partial path. Once
* again, we'll only do this if it looks as though the hash table
* won't exceed work_mem.
*/
if (grouped_rel->partial_pathlist)
{
Path *path = (Path *) linitial(grouped_rel->partial_pathlist);
hashaggtablesize = estimate_hashagg_tablesize(path,
agg_final_costs,
dNumGroups);
if (hashaggtablesize < work_mem * 1024L)
{
double total_groups = path->rows * path->parallel_workers;
path = (Path *) create_gather_path(root,
grouped_rel,
path,
partial_grouping_target,
NULL,
&total_groups);
add_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
path,
target,
AGG_HASHED,
AGGSPLIT_FINAL_DESERIAL,
parse->groupClause,
havingQual,
agg_final_costs,
dNumGroups));
}
}
}
}
/*
* add_partial_paths_to_grouping_rel
*
* Add partial paths to grouping relation. These paths are not fully
* aggregated; a FinalizeAggregate step is still required.
*/
static void
add_partial_paths_to_grouping_rel(PlannerInfo *root,
RelOptInfo *input_rel,
RelOptInfo *grouped_rel,
PathTarget *target,
PathTarget *partial_grouping_target,
AggClauseCosts *agg_partial_costs,
AggClauseCosts *agg_final_costs,
grouping_sets_data *gd,
bool can_sort,
bool can_hash,
List *havingQual)
{
Query *parse = root->parse;
Path *cheapest_partial_path = linitial(input_rel->partial_pathlist);
Size hashaggtablesize;
double dNumPartialGroups = 0;
ListCell *lc;
/* Estimate number of partial groups. */
dNumPartialGroups = get_number_of_groups(root,
cheapest_partial_path->rows,
gd);
if (can_sort)
{
/* This should have been checked previously */
Assert(parse->hasAggs || parse->groupClause);
/*
* Use any available suitably-sorted path as input, and also consider
* sorting the cheapest partial path.
*/
foreach(lc, input_rel->partial_pathlist)
{
Path *path = (Path *) lfirst(lc);
bool is_sorted;
is_sorted = pathkeys_contained_in(root->group_pathkeys,
path->pathkeys);
if (path == cheapest_partial_path || is_sorted)
{
/* Sort the cheapest partial path, if it isn't already */
if (!is_sorted)
path = (Path *) create_sort_path(root,
grouped_rel,
path,
root->group_pathkeys,
-1.0);
if (parse->hasAggs)
add_partial_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
path,
partial_grouping_target,
parse->groupClause ? AGG_SORTED : AGG_PLAIN,
AGGSPLIT_INITIAL_SERIAL,
parse->groupClause,
NIL,
agg_partial_costs,
dNumPartialGroups));
else
add_partial_path(grouped_rel, (Path *)
create_group_path(root,
grouped_rel,
path,
partial_grouping_target,
parse->groupClause,
NIL,
dNumPartialGroups));
}
}
}
if (can_hash)
{
/* Checked above */
Assert(parse->hasAggs || parse->groupClause);
hashaggtablesize =
estimate_hashagg_tablesize(cheapest_partial_path,
agg_partial_costs,
dNumPartialGroups);
/*
* Tentatively produce a partial HashAgg Path, depending on if it
* looks as if the hash table will fit in work_mem.
*/
if (hashaggtablesize < work_mem * 1024L)
{
add_partial_path(grouped_rel, (Path *)
create_agg_path(root,
grouped_rel,
cheapest_partial_path,
partial_grouping_target,
AGG_HASHED,
AGGSPLIT_INITIAL_SERIAL,
parse->groupClause,
NIL,
agg_partial_costs,
dNumPartialGroups));
}
}
}
/*
* can_parallel_agg
*
* Determines whether or not parallel grouping and/or aggregation is possible.
* Returns true when possible, false otherwise.
*/
static bool
can_parallel_agg(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *grouped_rel, const AggClauseCosts *agg_costs)
{
Query *parse = root->parse;
if (!grouped_rel->consider_parallel)
{
/* Not even parallel-safe. */
return false;
}
else if (input_rel->partial_pathlist == NIL)
{
/* Nothing to use as input for partial aggregate. */
return false;
}
else if (!parse->hasAggs && parse->groupClause == NIL)
{
/*
* We don't know how to do parallel aggregation unless we have either
* some aggregates or a grouping clause.
*/
return false;
}
else if (parse->groupingSets)
{
/* We don't know how to do grouping sets in parallel. */
return false;
}
else if (agg_costs->hasNonPartial || agg_costs->hasNonSerial)
{
/* Insufficient support for partial mode. */
return false;
}
/* Everything looks good. */
return true;
}
Reference in New Issue View Git Blame Copy Permalink