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PostgreSQL/src/backend/optimizer/path/xfunc.c
Bruce Momjian c60f70b53f Rename pg_plan and pg_eval to be more meaningful.
1997-12-11 17:36:58 +00:00

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/*-------------------------------------------------------------------------
*
* xfunc.c--
* Utility routines to handle expensive function optimization.
* Includes xfunc_trypullup(), which attempts early pullup of predicates
* to allow for maximal pruning.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/xfunc.c,v 1.8 1997/12/11 17:36:29 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <math.h> /* for MAXFLOAT on most systems */
#include <values.h> /* for MAXFLOAT on SunOS */
#include <string.h>
#include "postgres.h"
#include "nodes/pg_list.h"
#include "nodes/nodes.h"
#include "nodes/primnodes.h"
#include "nodes/relation.h"
#include "utils/elog.h"
#include "utils/palloc.h"
#include "utils/syscache.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "utils/syscache.h"
#include "catalog/pg_language.h"
#include "optimizer/xfunc.h"
#include "optimizer/clauses.h"
#include "optimizer/pathnode.h"
#include "optimizer/internal.h"
#include "optimizer/cost.h"
#include "optimizer/keys.h"
#include "optimizer/tlist.h"
#include "lib/lispsort.h"
#include "access/heapam.h"
#include "tcop/dest.h"
#include "storage/buf_internals.h" /* for NBuffers */
#include "optimizer/tlist.h" /* for get_expr */
#define ever ; 1 ;
/* local funcs */
static int
xfunc_card_unreferenced(Query *queryInfo,
Expr *clause, Relid referenced);
*/
/*
** xfunc_trypullup --
** Preliminary pullup of predicates, to allow for maximal pruning.
** Given a relation, check each of its paths and see if you can
** pullup clauses from its inner and outer.
*/
void
xfunc_trypullup(Rel rel)
{
LispValue y; /* list ptr */
CInfo maxcinfo; /* The CInfo to pull up, as calculated by
* xfunc_shouldpull() */
JoinPath curpath; /* current path in list */
int progress; /* has progress been made this time
* through? */
int clausetype;
do
{
progress = false; /* no progress yet in this iteration */
foreach(y, get_pathlist(rel))
{
curpath = (JoinPath) lfirst(y);
/*
* * for each operand, attempt to pullup predicates until
* first * failure.
*/
for (ever)
{
/* No, the following should NOT be '==' !! */
if (clausetype =
xfunc_shouldpull((Path) get_innerjoinpath(curpath),
curpath, INNER, &maxcinfo))
{
xfunc_pullup((Path) get_innerjoinpath(curpath),
curpath, maxcinfo, INNER, clausetype);
progress = true;
}
else
break;
}
for (ever)
{
/* No, the following should NOT be '==' !! */
if (clausetype =
xfunc_shouldpull((Path) get_outerjoinpath(curpath),
curpath, OUTER, &maxcinfo))
{
xfunc_pullup((Path) get_outerjoinpath(curpath),
curpath, maxcinfo, OUTER, clausetype);
progress = true;
}
else
break;
}
/*
* * make sure the unpruneable flag bubbles up, i.e. * if
* anywhere below us in the path pruneable is false, * then
* pruneable should be false here
*/
if (get_pruneable(get_parent(curpath)) &&
(!get_pruneable(get_parent
((Path) get_innerjoinpath(curpath))) ||
!get_pruneable(get_parent((Path)
get_outerjoinpath(curpath)))))
{
set_pruneable(get_parent(curpath), false);
progress = true;
}
}
} while (progress);
}
/*
** xfunc_shouldpull --
** find clause with highest rank, and decide whether to pull it up
** from child to parent. Currently we only pullup secondary join clauses
** that are in the pathclauseinfo. Secondary hash and sort clauses are
** left where they are.
** If we find an expensive function but decide *not* to pull it up,
** we'd better set the unpruneable flag. -- JMH, 11/11/92
**
** Returns: 0 if nothing left to pullup
** XFUNC_LOCPRD if a local predicate is to be pulled up
** XFUNC_JOINPRD if a secondary join predicate is to be pulled up
*/
int
xfunc_shouldpull(Query *queryInfo,
Path childpath,
JoinPath parentpath,
int whichchild,
CInfo *maxcinfopt) /* Out: pointer to clause to
* pullup */
{
LispValue clauselist,
tmplist; /* lists of clauses */
CInfo maxcinfo; /* clause to pullup */
LispValue primjoinclause /* primary join clause */
= xfunc_primary_join(parentpath);
Cost tmprank,
maxrank = (-1 * MAXFLOAT); /* ranks of clauses */
Cost joinselec = 0; /* selectivity of the join predicate */
Cost joincost = 0; /* join cost + primjoinclause cost */
int retval = XFUNC_LOCPRD;
clauselist = get_locclauseinfo(childpath);
if (clauselist != LispNil)
{
/* find local predicate with maximum rank */
for (tmplist = clauselist,
maxcinfo = (CInfo) lfirst(tmplist),
maxrank = xfunc_rank(get_clause(maxcinfo));
tmplist != LispNil;
tmplist = lnext(tmplist))
{
if ((tmprank = xfunc_rank(get_clause((CInfo) lfirst(tmplist))))
> maxrank)
{
maxcinfo = (CInfo) lfirst(tmplist);
maxrank = tmprank;
}
}
}
/*
* * If child is a join path, and there are multiple join clauses, *
* see if any join clause has even higher rank than the highest *
* local predicate
*/
if (is_join(childpath) && xfunc_num_join_clauses((JoinPath) childpath) > 1)
for (tmplist = get_pathclauseinfo((JoinPath) childpath);
tmplist != LispNil;
tmplist = lnext(tmplist))
{
if (tmplist != LispNil &&
(tmprank = xfunc_rank(get_clause((CInfo) lfirst(tmplist))))
> maxrank)
{
maxcinfo = (CInfo) lfirst(tmplist);
maxrank = tmprank;
retval = XFUNC_JOINPRD;
}
}
if (maxrank == (-1 * MAXFLOAT)) /* no expensive clauses */
return (0);
/*
* * Pullup over join if clause is higher rank than join, or if * join
* is nested loop and current path is inner child (note that *
* restrictions on the inner of a nested loop don't buy you anything
* -- * you still have to scan the entire inner relation each time). *
* Note that the cost of a secondary join clause is only what's *
* calculated by xfunc_expense(), since the actual joining * (i.e. the
* usual path_cost) is paid for by the primary join clause.
*/
if (primjoinclause != LispNil)
{
joinselec = compute_clause_selec(queryInfo, primjoinclause, LispNil);
joincost = xfunc_join_expense(parentpath, whichchild);
if (XfuncMode == XFUNC_PULLALL ||
(XfuncMode != XFUNC_WAIT &&
((joincost != 0 &&
(maxrank = xfunc_rank(get_clause(maxcinfo))) >
((joinselec - 1.0) / joincost))
|| (joincost == 0 && joinselec < 1)
|| (!is_join(childpath)
&& (whichchild == INNER)
&& IsA(parentpath, JoinPath)
&&!IsA(parentpath, HashPath)
&&!IsA(parentpath, MergePath)))))
{
*maxcinfopt = maxcinfo;
return (retval);
}
else if (maxrank != -(MAXFLOAT))
{
/*
* * we've left an expensive restriction below a join. Since *
* we may pullup this restriction in predmig.c, we'd best *
* set the Rel of this join to be unpruneable
*/
set_pruneable(get_parent(parentpath), false);
/* and fall through */
}
}
return (0);
}
/*
** xfunc_pullup --
** move clause from child pathnode to parent pathnode. This operation
** makes the child pathnode produce a larger relation than it used to.
** This means that we must construct a new Rel just for the childpath,
** although this Rel will not be added to the list of Rels to be joined up
** in the query; it's merely a parent for the new childpath.
** We also have to fix up the path costs of the child and parent.
**
** Now returns a pointer to the new pulled-up CInfo. -- JMH, 11/18/92
*/
CInfo
xfunc_pullup(Query *queryInfo,
Path childpath,
JoinPath parentpath,
CInfo cinfo, /* clause to pull up */
int whichchild, /* whether child is INNER or OUTER of join */
int clausetype) /* whether clause to pull is join or local */
{
Path newkid;
Rel newrel;
Cost pulled_selec;
Cost cost;
CInfo newinfo;
/* remove clause from childpath */
newkid = (Path) copyObject((Node) childpath);
if (clausetype == XFUNC_LOCPRD)
{
set_locclauseinfo(newkid,
xfunc_LispRemove((LispValue) cinfo,
(List) get_locclauseinfo(newkid)));
}
else
{
set_pathclauseinfo
((JoinPath) newkid,
xfunc_LispRemove((LispValue) cinfo,
(List) get_pathclauseinfo((JoinPath) newkid)));
}
/*
* * give the new child path its own Rel node that reflects the * lack
* of the pulled-up predicate
*/
pulled_selec = compute_clause_selec(queryInfo,
get_clause(cinfo), LispNil);
xfunc_copyrel(get_parent(newkid), &newrel);
set_parent(newkid, newrel);
set_pathlist(newrel, lcons(newkid, NIL));
set_unorderedpath(newrel, (PathPtr) newkid);
set_cheapestpath(newrel, (PathPtr) newkid);
set_size(newrel,
(Count) ((Cost) get_size(get_parent(childpath)) / pulled_selec));
/*
* * fix up path cost of newkid. To do this we subtract away all the *
* xfunc_costs of childpath, then recompute the xfunc_costs of newkid
*/
cost = get_path_cost(newkid) - xfunc_get_path_cost(childpath);
Assert(cost >= 0);
set_path_cost(newkid, cost);
cost = get_path_cost(newkid) + xfunc_get_path_cost(newkid);
set_path_cost(newkid, cost);
/*
* * We copy the cinfo, since it may appear in other plans, and we're
* going * to munge it. -- JMH, 7/22/92
*/
newinfo = (CInfo) copyObject((Node) cinfo);
/*
* * Fix all vars in the clause * to point to the right varno and
* varattno in parentpath
*/
xfunc_fixvars(get_clause(newinfo), newrel, whichchild);
/* add clause to parentpath, and fix up its cost. */
set_locclauseinfo(parentpath,
lispCons((LispValue) newinfo,
(LispValue) get_locclauseinfo(parentpath)));
/* put new childpath into the path tree */
if (whichchild == INNER)
{
set_innerjoinpath(parentpath, (pathPtr) newkid);
}
else
{
set_outerjoinpath(parentpath, (pathPtr) newkid);
}
/*
* * recompute parentpath cost from scratch -- the cost * of the join
* method has changed
*/
cost = xfunc_total_path_cost(parentpath);
set_path_cost(parentpath, cost);
return (newinfo);
}
/*
** calculate (selectivity-1)/cost.
*/
Cost
xfunc_rank(Query *queryInfo, LispValue clause)
{
Cost selec = compute_clause_selec(queryInfo, clause, LispNil);
Cost cost = xfunc_expense(queryInfo, clause);
if (cost == 0)
if (selec > 1)
return (MAXFLOAT);
else
return (-(MAXFLOAT));
return ((selec - 1) / cost);
}
/*
** Find the "global" expense of a clause; i.e. the local expense divided
** by the cardinalities of all the base relations of the query that are *not*
** referenced in the clause.
*/
Cost
xfunc_expense(Query *queryInfo, clause)
LispValue clause;
{
Cost cost = xfunc_local_expense(clause);
if (cost)
{
Count card = xfunc_card_unreferenced(queryInfo, clause, LispNil);
if (card)
cost /= card;
}
return (cost);
}
/*
** xfunc_join_expense --
** Find global expense of a join clause
*/
Cost
xfunc_join_expense(Query *queryInfo, JoinPath path, int whichchild)
{
LispValue primjoinclause = xfunc_primary_join(path);
/*
* * the second argument to xfunc_card_unreferenced reflects all the *
* relations involved in the join clause, i.e. all the relids in the
* Rel * of the join clause
*/
Count card = 0;
Cost cost = xfunc_expense_per_tuple(path, whichchild);
card = xfunc_card_unreferenced(queryInfo,
primjoinclause,
get_relids(get_parent(path)));
if (primjoinclause)
cost += xfunc_local_expense(primjoinclause);
if (card)
cost /= card;
return (cost);
}
/*
** Recursively find the per-tuple expense of a clause. See
** xfunc_func_expense for more discussion.
*/
Cost
xfunc_local_expense(LispValue clause)
{
Cost cost = 0; /* running expense */
LispValue tmpclause;
/* First handle the base case */
if (IsA(clause, Const) ||IsA(clause, Var) ||IsA(clause, Param))
return (0);
/* now other stuff */
else if (IsA(clause, Iter))
/* Too low. Should multiply by the expected number of iterations. */
return (xfunc_local_expense(get_iterexpr((Iter) clause)));
else if (IsA(clause, ArrayRef))
return (xfunc_local_expense(get_refexpr((ArrayRef) clause)));
else if (fast_is_clause(clause))
return (xfunc_func_expense((LispValue) get_op(clause),
(LispValue) get_opargs(clause)));
else if (fast_is_funcclause(clause))
return (xfunc_func_expense((LispValue) get_function(clause),
(LispValue) get_funcargs(clause)));
else if (fast_not_clause(clause))
return (xfunc_local_expense(lsecond(clause)));
else if (fast_or_clause(clause))
{
/* find cost of evaluating each disjunct */
for (tmpclause = lnext(clause); tmpclause != LispNil;
tmpclause = lnext(tmpclause))
cost += xfunc_local_expense(lfirst(tmpclause));
return (cost);
}
else
{
elog(WARN, "Clause node of undetermined type");
return (-1);
}
}
/*
** xfunc_func_expense --
** given a Func or Oper and its args, find its expense.
** Note: in Stonebraker's SIGMOD '91 paper, he uses a more complicated metric
** than the one here. We can ignore the expected number of tuples for
** our calculations; we just need the per-tuple expense. But he also
** proposes components to take into account the costs of accessing disk and
** archive. We didn't adopt that scheme here; eventually the vacuum
** cleaner should be able to tell us what percentage of bytes to find on
** which storage level, and that should be multiplied in appropriately
** in the cost function below. Right now we don't model the cost of
** accessing secondary or tertiary storage, since we don't have sufficient
** stats to do it right.
*/
Cost
xfunc_func_expense(LispValue node, LispValue args)
{
HeapTuple tupl; /* the pg_proc tuple for each function */
Form_pg_proc proc; /* a data structure to hold the pg_proc
* tuple */
int width = 0; /* byte width of the field referenced by
* each clause */
RegProcedure funcid; /* ID of function associate with node */
Cost cost = 0; /* running expense */
LispValue tmpclause;
LispValue operand; /* one operand of an operator */
if (IsA(node, Oper))
{
/* don't trust the opid in the Oper node. Use the opno. */
if (!(funcid = get_opcode(get_opno((Oper) node))))
elog(WARN, "Oper's function is undefined");
}
else
{
funcid = get_funcid((Func) node);
}
/* look up tuple in cache */
tupl = SearchSysCacheTuple(PROOID, ObjectIdGetDatum(funcid), 0, 0, 0);
if (!HeapTupleIsValid(tupl))
elog(WARN, "Cache lookup failed for procedure %d", funcid);
proc = (Form_pg_proc) GETSTRUCT(tupl);
/*
* * if it's a Postquel function, its cost is stored in the *
* associated plan.
*/
if (proc->prolang == SQLlanguageId)
{
LispValue tmpplan;
List planlist;
if (IsA(node, Oper) ||get_func_planlist((Func) node) == LispNil)
{
Oid *argOidVect; /* vector of argtypes */
char *pq_src; /* text of PQ function */
int nargs; /* num args to PQ function */
QueryTreeList *queryTree_list; /* dummy variable */
/*
* * plan the function, storing it in the Func node for later *
* use by the executor.
*/
pq_src = (char *) textout(&(proc->prosrc));
nargs = proc->pronargs;
if (nargs > 0)
argOidVect = proc->proargtypes;
planlist = (List) pg_parse_and_plan(pq_src, argOidVect, nargs,
&parseTree_list, None);
if (IsA(node, Func))
set_func_planlist((Func) node, planlist);
}
else
{ /* plan has been cached inside the Func
* node already */
planlist = get_func_planlist((Func) node);
}
/*
* * Return the sum of the costs of the plans (the PQ function *
* may have many queries in its body).
*/
foreach(tmpplan, planlist)
cost += get_cost((Plan) lfirst(tmpplan));
return (cost);
}
else
{ /* it's a C function */
/*
* * find the cost of evaluating the function's arguments * and
* the width of the operands
*/
for (tmpclause = args; tmpclause != LispNil;
tmpclause = lnext(tmpclause))
{
if ((operand = lfirst(tmpclause)) != LispNil)
{
cost += xfunc_local_expense(operand);
width += xfunc_width(operand);
}
}
/*
* * when stats become available, add in cost of accessing
* secondary * and tertiary storage here.
*/
return (cost +
(Cost) proc->propercall_cpu +
(Cost) proc->properbyte_cpu * (Cost) proc->probyte_pct / 100.00 *
(Cost) width
/*
* Pct_of_obj_in_mem DISK_COST * proc->probyte_pct/100.00 * width
* Pct_of_obj_on_disk + ARCH_COST * proc->probyte_pct/100.00 *
* width Pct_of_obj_on_arch
*/
);
}
}
/*
** xfunc_width --
** recursively find the width of a expression
*/
int
xfunc_width(LispValue clause)
{
Relation rd; /* Relation Descriptor */
HeapTuple tupl; /* structure to hold a cached tuple */
TypeTupleForm type; /* structure to hold a type tuple */
int retval = 0;
if (IsA(clause, Const))
{
/* base case: width is the width of this constant */
retval = get_constlen((Const) clause);
goto exit;
}
else if (IsA(clause, ArrayRef))
{
/* base case: width is width of the refelem within the array */
retval = get_refelemlength((ArrayRef) clause);
goto exit;
}
else if (IsA(clause, Var))
{
/* base case: width is width of this attribute */
tupl = SearchSysCacheTuple(TYPOID,
PointerGetDatum(get_vartype((Var) clause)),
0, 0, 0);
if (!HeapTupleIsValid(tupl))
elog(WARN, "Cache lookup failed for type %d",
get_vartype((Var) clause));
type = (TypeTupleForm) GETSTRUCT(tupl);
if (get_varattno((Var) clause) == 0)
{
/* clause is a tuple. Get its width */
rd = heap_open(type->typrelid);
retval = xfunc_tuple_width(rd);
heap_close(rd);
}
else
{
/* attribute is a base type */
retval = type->typlen;
}
goto exit;
}
else if (IsA(clause, Param))
{
if (typeidTypeRelid(get_paramtype((Param) clause)))
{
/* Param node returns a tuple. Find its width */
rd = heap_open(typeidTypeRelid(get_paramtype((Param) clause)));
retval = xfunc_tuple_width(rd);
heap_close(rd);
}
else if (get_param_tlist((Param) clause) != LispNil)
{
/* Param node projects a complex type */
Assert(length(get_param_tlist((Param) clause)) == 1); /* sanity */
retval =
xfunc_width((LispValue)
get_expr(lfirst(get_param_tlist((Param) clause))));
}
else
{
/* Param node returns a base type */
retval = typeLen(typeidType(get_paramtype((Param) clause)));
}
goto exit;
}
else if (IsA(clause, Iter))
{
/*
* * An Iter returns a setof things, so return the width of a
* single * thing. * Note: THIS MAY NOT WORK RIGHT WHEN AGGS GET
* FIXED, * SINCE AGG FUNCTIONS CHEW ON THE WHOLE SETOF THINGS!!!! *
* This whole Iter business is bogus, anyway.
*/
retval = xfunc_width(get_iterexpr((Iter) clause));
goto exit;
}
else if (fast_is_clause(clause))
{
/*
* * get function associated with this Oper, and treat this as * a
* Func
*/
tupl = SearchSysCacheTuple(OPROID,
ObjectIdGetDatum(get_opno((Oper) get_op(clause))),
0, 0, 0);
if (!HeapTupleIsValid(tupl))
elog(WARN, "Cache lookup failed for procedure %d",
get_opno((Oper) get_op(clause)));
return (xfunc_func_width
((RegProcedure) (((OperatorTupleForm) (GETSTRUCT(tupl)))->oprcode),
(LispValue) get_opargs(clause)));
}
else if (fast_is_funcclause(clause))
{
Func func = (Func) get_function(clause);
if (get_func_tlist(func) != LispNil)
{
/*
* this function has a projection on it. Get the length of
* the projected attribute
*/
Assert(length(get_func_tlist(func)) == 1); /* sanity */
retval =
xfunc_width((LispValue)
get_expr(lfirst(get_func_tlist(func))));
goto exit;
}
else
{
return (xfunc_func_width((RegProcedure) get_funcid(func),
(LispValue) get_funcargs(clause)));
}
}
else
{
elog(WARN, "Clause node of undetermined type");
return (-1);
}
exit:
if (retval == -1)
retval = VARLEN_DEFAULT;
return (retval);
}
/*
** xfunc_card_unreferenced:
** find all relations not referenced in clause, and multiply their
** cardinalities. Ignore relation of cardinality 0.
** User may pass in referenced list, if they know it (useful
** for joins).
*/
static Count
xfunc_card_unreferenced(Query *queryInfo,
LispValue clause, Relid referenced)
{
Relid unreferenced,
allrelids = LispNil;
LispValue temp;
/* find all relids of base relations referenced in query */
foreach(temp, queryInfo->base_relation_list_)
{
Assert(lnext(get_relids((Rel) lfirst(temp))) == LispNil);
allrelids = lappend(allrelids,
lfirst(get_relids((Rel) lfirst(temp))));
}
/* find all relids referenced in query but not in clause */
if (!referenced)
referenced = xfunc_find_references(clause);
unreferenced = set_difference(allrelids, referenced);
return (xfunc_card_product(unreferenced));
}
/*
** xfunc_card_product
** multiple together cardinalities of a list relations.
*/
Count
xfunc_card_product(Query *queryInfo, Relid relids)
{
LispValue cinfonode;
LispValue temp;
Rel currel;
Cost tuples;
Count retval = 0;
foreach(temp, relids)
{
currel = get_rel(lfirst(temp));
tuples = get_tuples(currel);
if (tuples)
{ /* not of cardinality 0 */
/* factor in the selectivity of all zero-cost clauses */
foreach(cinfonode, get_clauseinfo(currel))
{
if (!xfunc_expense(queryInfo, get_clause((CInfo) lfirst(cinfonode))))
tuples *=
compute_clause_selec(queryInfo,
get_clause((CInfo) lfirst(cinfonode)),
LispNil);
}
if (retval == 0)
retval = tuples;
else
retval *= tuples;
}
}
if (retval == 0)
retval = 1; /* saves caller from dividing by zero */
return (retval);
}
/*
** xfunc_find_references:
** Traverse a clause and find all relids referenced in the clause.
*/
List
xfunc_find_references(LispValue clause)
{
List retval = (List) LispNil;
LispValue tmpclause;
/* Base cases */
if (IsA(clause, Var))
return (lispCons(lfirst(get_varid((Var) clause)), LispNil));
else if (IsA(clause, Const) ||IsA(clause, Param))
return ((List) LispNil);
/* recursion */
else if (IsA(clause, Iter))
/*
* Too low. Should multiply by the expected number of iterations.
* maybe
*/
return (xfunc_find_references(get_iterexpr((Iter) clause)));
else if (IsA(clause, ArrayRef))
return (xfunc_find_references(get_refexpr((ArrayRef) clause)));
else if (fast_is_clause(clause))
{
/* string together result of all operands of Oper */
for (tmpclause = (LispValue) get_opargs(clause); tmpclause != LispNil;
tmpclause = lnext(tmpclause))
retval = nconc(retval, xfunc_find_references(lfirst(tmpclause)));
return (retval);
}
else if (fast_is_funcclause(clause))
{
/* string together result of all args of Func */
for (tmpclause = (LispValue) get_funcargs(clause);
tmpclause != LispNil;
tmpclause = lnext(tmpclause))
retval = nconc(retval, xfunc_find_references(lfirst(tmpclause)));
return (retval);
}
else if (fast_not_clause(clause))
return (xfunc_find_references(lsecond(clause)));
else if (fast_or_clause(clause))
{
/* string together result of all operands of OR */
for (tmpclause = lnext(clause); tmpclause != LispNil;
tmpclause = lnext(tmpclause))
retval = nconc(retval, xfunc_find_references(lfirst(tmpclause)));
return (retval);
}
else
{
elog(WARN, "Clause node of undetermined type");
return ((List) LispNil);
}
}
/*
** xfunc_primary_join:
** Find the primary join clause: for Hash and Merge Joins, this is the
** min rank Hash or Merge clause, while for Nested Loop it's the
** min rank pathclause
*/
LispValue
xfunc_primary_join(JoinPath pathnode)
{
LispValue joinclauselist = get_pathclauseinfo(pathnode);
CInfo mincinfo;
LispValue tmplist;
LispValue minclause = LispNil;
Cost minrank,
tmprank;
if (IsA(pathnode, MergePath))
{
for (tmplist = get_path_mergeclauses((MergePath) pathnode),
minclause = lfirst(tmplist),
minrank = xfunc_rank(minclause);
tmplist != LispNil;
tmplist = lnext(tmplist))
if ((tmprank = xfunc_rank(lfirst(tmplist)))
< minrank)
{
minrank = tmprank;
minclause = lfirst(tmplist);
}
return (minclause);
}
else if (IsA(pathnode, HashPath))
{
for (tmplist = get_path_hashclauses((HashPath) pathnode),
minclause = lfirst(tmplist),
minrank = xfunc_rank(minclause);
tmplist != LispNil;
tmplist = lnext(tmplist))
if ((tmprank = xfunc_rank(lfirst(tmplist)))
< minrank)
{
minrank = tmprank;
minclause = lfirst(tmplist);
}
return (minclause);
}
/* if we drop through, it's nested loop join */
if (joinclauselist == LispNil)
return (LispNil);
for (tmplist = joinclauselist, mincinfo = (CInfo) lfirst(joinclauselist),
minrank = xfunc_rank(get_clause((CInfo) lfirst(tmplist)));
tmplist != LispNil;
tmplist = lnext(tmplist))
if ((tmprank = xfunc_rank(get_clause((CInfo) lfirst(tmplist))))
< minrank)
{
minrank = tmprank;
mincinfo = (CInfo) lfirst(tmplist);
}
return ((LispValue) get_clause(mincinfo));
}
/*
** xfunc_get_path_cost
** get the expensive function costs of the path
*/
Cost
xfunc_get_path_cost(Query *queryInfo, Path pathnode)
{
Cost cost = 0;
LispValue tmplist;
Cost selec = 1.0;
/*
* * first add in the expensive local function costs. * We ensure that
* the clauses are sorted by rank, so that we * know (via
* selectivities) the number of tuples that will be checked * by each
* function. If we're not doing any optimization of expensive *
* functions, we don't sort.
*/
if (XfuncMode != XFUNC_OFF)
set_locclauseinfo(pathnode, lisp_qsort(get_locclauseinfo(pathnode),
xfunc_cinfo_compare));
for (tmplist = get_locclauseinfo(pathnode), selec = 1.0;
tmplist != LispNil;
tmplist = lnext(tmplist))
{
cost += (Cost) (xfunc_local_expense(get_clause((CInfo) lfirst(tmplist)))
* (Cost) get_tuples(get_parent(pathnode)) * selec);
selec *= compute_clause_selec(queryInfo,
get_clause((CInfo) lfirst(tmplist)),
LispNil);
}
/*
* * Now add in any node-specific expensive function costs. * Again,
* we must ensure that the clauses are sorted by rank.
*/
if (IsA(pathnode, JoinPath))
{
if (XfuncMode != XFUNC_OFF)
set_pathclauseinfo((JoinPath) pathnode, lisp_qsort
(get_pathclauseinfo((JoinPath) pathnode),
xfunc_cinfo_compare));
for (tmplist = get_pathclauseinfo((JoinPath) pathnode), selec = 1.0;
tmplist != LispNil;
tmplist = lnext(tmplist))
{
cost += (Cost) (xfunc_local_expense(get_clause((CInfo) lfirst(tmplist)))
* (Cost) get_tuples(get_parent(pathnode)) * selec);
selec *= compute_clause_selec(queryInfo,
get_clause((CInfo) lfirst(tmplist)),
LispNil);
}
}
if (IsA(pathnode, HashPath))
{
if (XfuncMode != XFUNC_OFF)
set_path_hashclauses
((HashPath) pathnode,
lisp_qsort(get_path_hashclauses((HashPath) pathnode),
xfunc_clause_compare));
for (tmplist = get_path_hashclauses((HashPath) pathnode), selec = 1.0;
tmplist != LispNil;
tmplist = lnext(tmplist))
{
cost += (Cost) (xfunc_local_expense(lfirst(tmplist))
* (Cost) get_tuples(get_parent(pathnode)) * selec);
selec *= compute_clause_selec(queryInfo,
lfirst(tmplist), LispNil);
}
}
if (IsA(pathnode, MergePath))
{
if (XfuncMode != XFUNC_OFF)
set_path_mergeclauses
((MergePath) pathnode,
lisp_qsort(get_path_mergeclauses((MergePath) pathnode),
xfunc_clause_compare));
for (tmplist = get_path_mergeclauses((MergePath) pathnode), selec = 1.0;
tmplist != LispNil;
tmplist = lnext(tmplist))
{
cost += (Cost) (xfunc_local_expense(lfirst(tmplist))
* (Cost) get_tuples(get_parent(pathnode)) * selec);
selec *= compute_clause_selec(queryInfo,
lfirst(tmplist), LispNil);
}
}
Assert(cost >= 0);
return (cost);
}
/*
** Recalculate the cost of a path node. This includes the basic cost of the
** node, as well as the cost of its expensive functions.
** We need to do this to the parent after pulling a clause from a child into a
** parent. Thus we should only be calling this function on JoinPaths.
*/
Cost
xfunc_total_path_cost(JoinPath pathnode)
{
Cost cost = xfunc_get_path_cost((Path) pathnode);
Assert(IsA(pathnode, JoinPath));
if (IsA(pathnode, MergePath))
{
MergePath mrgnode = (MergePath) pathnode;
cost += cost_mergesort(get_path_cost((Path) get_outerjoinpath(mrgnode)),
get_path_cost((Path) get_innerjoinpath(mrgnode)),
get_outersortkeys(mrgnode),
get_innersortkeys(mrgnode),
get_tuples(get_parent((Path) get_outerjoinpath
(mrgnode))),
get_tuples(get_parent((Path) get_innerjoinpath
(mrgnode))),
get_width(get_parent((Path) get_outerjoinpath
(mrgnode))),
get_width(get_parent((Path) get_innerjoinpath
(mrgnode))));
Assert(cost >= 0);
return (cost);
}
else if (IsA(pathnode, HashPath))
{
HashPath hashnode = (HashPath) pathnode;
cost += cost_hashjoin(get_path_cost((Path) get_outerjoinpath(hashnode)),
get_path_cost((Path) get_innerjoinpath(hashnode)),
get_outerhashkeys(hashnode),
get_innerhashkeys(hashnode),
get_tuples(get_parent((Path) get_outerjoinpath
(hashnode))),
get_tuples(get_parent((Path) get_innerjoinpath
(hashnode))),
get_width(get_parent((Path) get_outerjoinpath
(hashnode))),
get_width(get_parent((Path) get_innerjoinpath
(hashnode))));
Assert(cost >= 0);
return (cost);
}
else
/* Nested Loop Join */
{
cost += cost_nestloop(get_path_cost((Path) get_outerjoinpath(pathnode)),
get_path_cost((Path) get_innerjoinpath(pathnode)),
get_tuples(get_parent((Path) get_outerjoinpath
(pathnode))),
get_tuples(get_parent((Path) get_innerjoinpath
(pathnode))),
get_pages(get_parent((Path) get_outerjoinpath
(pathnode))),
IsA(get_innerjoinpath(pathnode), IndexPath));
Assert(cost >= 0);
return (cost);
}
}
/*
** xfunc_expense_per_tuple --
** return the expense of the join *per-tuple* of the input relation.
** The cost model here is that a join costs
** k*card(outer)*card(inner) + l*card(outer) + m*card(inner) + n
**
** We treat the l and m terms by considering them to be like restrictions
** constrained to be right under the join. Thus the cost per inner and
** cost per outer of the join is different, reflecting these virtual nodes.
**
** The cost per tuple of outer is k + l/referenced(inner). Cost per tuple
** of inner is k + m/referenced(outer).
** The constants k, l, m and n depend on the join method. Measures here are
** based on the costs in costsize.c, with fudging for HashJoin and Sorts to
** make it fit our model (the 'q' in HashJoin results in a
** card(outer)/card(inner) term, and sorting results in a log term.
*/
Cost
xfunc_expense_per_tuple(JoinPath joinnode, int whichchild)
{
Rel outerrel = get_parent((Path) get_outerjoinpath(joinnode));
Rel innerrel = get_parent((Path) get_innerjoinpath(joinnode));
Count outerwidth = get_width(outerrel);
Count outers_per_page = ceil(BLCKSZ / (outerwidth + sizeof(HeapTupleData)));
if (IsA(joinnode, HashPath))
{
if (whichchild == INNER)
return ((1 + _CPU_PAGE_WEIGHT_) * outers_per_page / NBuffers);
else
return (((1 + _CPU_PAGE_WEIGHT_) * outers_per_page / NBuffers)
+ _CPU_PAGE_WEIGHT_
/ xfunc_card_product(get_relids(innerrel)));
}
else if (IsA(joinnode, MergePath))
{
/* assumes sort exists, and costs one (I/O + CPU) per tuple */
if (whichchild == INNER)
return ((2 * _CPU_PAGE_WEIGHT_ + 1)
/ xfunc_card_product(get_relids(outerrel)));
else
return ((2 * _CPU_PAGE_WEIGHT_ + 1)
/ xfunc_card_product(get_relids(innerrel)));
}
else
/* nestloop */
{
Assert(IsA(joinnode, JoinPath));
return (_CPU_PAGE_WEIGHT_);
}
}
/*
** xfunc_fixvars --
** After pulling up a clause, we must walk its expression tree, fixing Var
** nodes to point to the correct varno (either INNER or OUTER, depending
** on which child the clause was pulled from), and the right varattno in the
** target list of the child's former relation. If the target list of the
** child Rel does not contain the attribute we need, we add it.
*/
void
xfunc_fixvars(LispValue clause, /* clause being pulled up */
Rel rel, /* rel it's being pulled from */
int varno) /* whether rel is INNER or OUTER of join */
{
LispValue tmpclause; /* temporary variable */
TargetEntry *tle; /* tlist member corresponding to var */
if (IsA(clause, Const) ||IsA(clause, Param))
return;
else if (IsA(clause, Var))
{
/* here's the meat */
tle = tlistentry_member((Var) clause, get_targetlist(rel));
if (tle == LispNil)
{
/*
* * The attribute we need is not in the target list, * so we
* have to add it. *
*
*/
add_tl_element(rel, (Var) clause);
tle = tlistentry_member((Var) clause, get_targetlist(rel));
}
set_varno(((Var) clause), varno);
set_varattno(((Var) clause), get_resno(get_resdom(get_entry(tle))));
}
else if (IsA(clause, Iter))
xfunc_fixvars(get_iterexpr((Iter) clause), rel, varno);
else if (fast_is_clause(clause))
{
xfunc_fixvars(lfirst(lnext(clause)), rel, varno);
xfunc_fixvars(lfirst(lnext(lnext(clause))), rel, varno);
}
else if (fast_is_funcclause(clause))
for (tmpclause = lnext(clause); tmpclause != LispNil;
tmpclause = lnext(tmpclause))
xfunc_fixvars(lfirst(tmpclause), rel, varno);
else if (fast_not_clause(clause))
xfunc_fixvars(lsecond(clause), rel, varno);
else if (fast_or_clause(clause))
for (tmpclause = lnext(clause); tmpclause != LispNil;
tmpclause = lnext(tmpclause))
xfunc_fixvars(lfirst(tmpclause), rel, varno);
else
{
elog(WARN, "Clause node of undetermined type");
}
}
/*
** Comparison function for lisp_qsort() on a list of CInfo's.
** arg1 and arg2 should really be of type (CInfo *).
*/
int
xfunc_cinfo_compare(void *arg1, void *arg2)
{
CInfo info1 = *(CInfo *) arg1;
CInfo info2 = *(CInfo *) arg2;
LispValue clause1 = (LispValue) get_clause(info1),
clause2 = (LispValue) get_clause(info2);
return (xfunc_clause_compare((void *) &clause1, (void *) &clause2));
}
/*
** xfunc_clause_compare: comparison function for lisp_qsort() that compares two
** clauses based on expense/(1 - selectivity)
** arg1 and arg2 are really pointers to clauses.
*/
int
xfunc_clause_compare(void *arg1, void *arg2)
{
LispValue clause1 = *(LispValue *) arg1;
LispValue clause2 = *(LispValue *) arg2;
Cost rank1, /* total xfunc rank of clause1 */
rank2; /* total xfunc rank of clause2 */
rank1 = xfunc_rank(clause1);
rank2 = xfunc_rank(clause2);
if (rank1 < rank2)
return (-1);
else if (rank1 == rank2)
return (0);
else
return (1);
}
/*
** xfunc_disjunct_sort --
** given a list of clauses, for each clause sort the disjuncts by cost
** (this assumes the predicates have been converted to Conjunctive NF)
** Modifies the clause list!
*/
void
xfunc_disjunct_sort(LispValue clause_list)
{
LispValue temp;
foreach(temp, clause_list)
if (or_clause(lfirst(temp)))
lnext(lfirst(temp)) =
lisp_qsort(lnext(lfirst(temp)), xfunc_disjunct_compare);
}
/*
** xfunc_disjunct_compare: comparison function for qsort() that compares two
** disjuncts based on cost/selec.
** arg1 and arg2 are really pointers to disjuncts
*/
int
xfunc_disjunct_compare(Query *queryInfo, void *arg1, void *arg2)
{
LispValue disjunct1 = *(LispValue *) arg1;
LispValue disjunct2 = *(LispValue *) arg2;
Cost cost1, /* total cost of disjunct1 */
cost2, /* total cost of disjunct2 */
selec1,
selec2;
Cost rank1,
rank2;
cost1 = xfunc_expense(queryInfo, disjunct1);
cost2 = xfunc_expense(queryInfo, disjunct2);
selec1 = compute_clause_selec(queryInfo,
disjunct1, LispNil);
selec2 = compute_clause_selec(queryInfo,
disjunct2, LispNil);
if (selec1 == 0)
rank1 = MAXFLOAT;
else if (cost1 == 0)
rank1 = 0;
else
rank1 = cost1 / selec1;
if (selec2 == 0)
rank2 = MAXFLOAT;
else if (cost2 == 0)
rank2 = 0;
else
rank2 = cost2 / selec2;
if (rank1 < rank2)
return (-1);
else if (rank1 == rank2)
return (0);
else
return (1);
}
/* ------------------------ UTILITY FUNCTIONS ------------------------------- */
/*
** xfunc_func_width --
** Given a function OID and operands, find the width of the return value.
*/
int
xfunc_func_width(RegProcedure funcid, LispValue args)
{
Relation rd; /* Relation Descriptor */
HeapTuple tupl; /* structure to hold a cached tuple */
Form_pg_proc proc; /* structure to hold the pg_proc tuple */
TypeTupleForm type; /* structure to hold the pg_type tuple */
LispValue tmpclause;
int retval;
/* lookup function and find its return type */
Assert(RegProcedureIsValid(funcid));
tupl = SearchSysCacheTuple(PROOID, ObjectIdGetDatum(funcid), 0, 0, 0);
if (!HeapTupleIsValid(tupl))
elog(WARN, "Cache lookup failed for procedure %d", funcid);
proc = (Form_pg_proc) GETSTRUCT(tupl);
/* if function returns a tuple, get the width of that */
if (typeidTypeRelid(proc->prorettype))
{
rd = heap_open(typeidTypeRelid(proc->prorettype));
retval = xfunc_tuple_width(rd);
heap_close(rd);
goto exit;
}
else
/* function returns a base type */
{
tupl = SearchSysCacheTuple(TYPOID,
ObjectIdGetDatum(proc->prorettype),
0, 0, 0);
if (!HeapTupleIsValid(tupl))
elog(WARN, "Cache lookup failed for type %d", proc->prorettype);
type = (TypeTupleForm) GETSTRUCT(tupl);
/* if the type length is known, return that */
if (type->typlen != -1)
{
retval = type->typlen;
goto exit;
}
else
/* estimate the return size */
{
/* find width of the function's arguments */
for (tmpclause = args; tmpclause != LispNil;
tmpclause = lnext(tmpclause))
retval += xfunc_width(lfirst(tmpclause));
/* multiply by outin_ratio */
retval = (int) (proc->prooutin_ratio / 100.0 * retval);
goto exit;
}
}
exit:
return (retval);
}
/*
** xfunc_tuple_width --
** Return the sum of the lengths of all the attributes of a given relation
*/
int
xfunc_tuple_width(Relation rd)
{
int i;
int retval = 0;
TupleDesc tdesc = RelationGetTupleDescriptor(rd);
for (i = 0; i < tdesc->natts; i++)
{
if (tdesc->attrs[i]->attlen != -1)
retval += tdesc->attrs[i]->attlen;
else
retval += VARLEN_DEFAULT;
}
return (retval);
}
/*
** xfunc_num_join_clauses --
** Find the number of join clauses associated with this join path
*/
int
xfunc_num_join_clauses(JoinPath path)
{
int num = length(get_pathclauseinfo(path));
if (IsA(path, MergePath))
return (num + length(get_path_mergeclauses((MergePath) path)));
else if (IsA(path, HashPath))
return (num + length(get_path_hashclauses((HashPath) path)));
else
return (num);
}
/*
** xfunc_LispRemove --
** Just like LispRemove, but it whines if the item to be removed ain't there
*/
LispValue
xfunc_LispRemove(LispValue foo, List bar)
{
LispValue temp = LispNil;
LispValue result = LispNil;
int sanity = false;
for (temp = bar; !null(temp); temp = lnext(temp))
if (!equal((Node) (foo), (Node) (lfirst(temp))))
{
result = lappend(result, lfirst(temp));
}
else
sanity = true; /* found a matching item to remove! */
if (!sanity)
elog(WARN, "xfunc_LispRemove: didn't find a match!");
return (result);
}
#define Node_Copy(a, b, c, d) \
if (NodeCopy((Node)((a)->d), (Node*)&((b)->d), c) != true) { \
return false; \
}
/*
** xfunc_copyrel --
** Just like _copyRel, but doesn't copy the paths
*/
bool
xfunc_copyrel(Rel from, Rel *to)
{
Rel newnode;
Pointer (*alloc) () = palloc;
/* COPY_CHECKARGS() */
if (to == NULL)
{
return false;
}
/* COPY_CHECKNULL() */
if (from == NULL)
{
(*to) = NULL;
return true;
}
/* COPY_NEW(c) */
newnode = (Rel) (*alloc) (classSize(Rel));
if (newnode == NULL)
{
return false;
}
/* ----------------
* copy node superclass fields
* ----------------
*/
CopyNodeFields((Node) from, (Node) newnode, alloc);
/* ----------------
* copy remainder of node
* ----------------
*/
Node_Copy(from, newnode, alloc, relids);
newnode->indexed = from->indexed;
newnode->pages = from->pages;
newnode->tuples = from->tuples;
newnode->size = from->size;
newnode->width = from->width;
Node_Copy(from, newnode, alloc, targetlist);
/*
* No!!!! Node_Copy(from, newnode, alloc, pathlist);
* Node_Copy(from, newnode, alloc, unorderedpath); Node_Copy(from,
* newnode, alloc, cheapestpath);
*/
#if 0 /* can't use Node_copy now. 2/95 -ay */
Node_Copy(from, newnode, alloc, classlist);
Node_Copy(from, newnode, alloc, indexkeys);
Node_Copy(from, newnode, alloc, ordering);
#endif
Node_Copy(from, newnode, alloc, clauseinfo);
Node_Copy(from, newnode, alloc, joininfo);
Node_Copy(from, newnode, alloc, innerjoin);
Node_Copy(from, newnode, alloc, superrels);
(*to) = newnode;
return true;
}
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