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Allow to lock views.

Browse Source 
Now all tables used in view definitions can be recursively locked by a
LOCK command.

Author: Yugo Nagata
Reviewed by Robert Haas, Thomas Munro and me.

Discussion: https://postgr.es/m/20171011183629.eb2817b3.nagata%40sraoss.co.jp
This commit is contained in:
Tatsuo Ishii 2018-03-30 09:18:02 +09:00
parent fb60478011
commit 34c20de4d0
4 changed files with 285 additions and 18 deletions
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5
doc/src/sgml/ref/lock.sgml
View File

@ -45,6 +45,11 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
end.)
</para>
<para>
When a view is specified to be locked, all relations appearing in the view
definition query are also locked recursively with the same lock mode.
</para>
<para>
When acquiring locks automatically for commands that reference
tables, <productname>PostgreSQL</productname> always uses the least

139
src/backend/commands/lockcmds.c
View File

@ -23,11 +23,15 @@
#include "utils/acl.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "rewrite/rewriteHandler.h"
#include "access/heapam.h"
#include "nodes/nodeFuncs.h"
static void LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait);
static AclResult LockTableAclCheck(Oid relid, LOCKMODE lockmode);
static void LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, Oid userid);
static AclResult LockTableAclCheck(Oid relid, LOCKMODE lockmode, Oid userid);
static void RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid,
Oid oldrelid, void *arg);
static void LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait);
/*
* LOCK TABLE
@ -62,8 +66,10 @@ LockTableCommand(LockStmt *lockstmt)
RangeVarCallbackForLockTable,
(void *) &lockstmt->mode);
if (recurse)
LockTableRecurse(reloid, lockstmt->mode, lockstmt->nowait);
if (get_rel_relkind(reloid) == RELKIND_VIEW)
LockViewRecurse(reloid, reloid, lockstmt->mode, lockstmt->nowait);
else if (recurse)
LockTableRecurse(reloid, lockstmt->mode, lockstmt->nowait, GetUserId());
}
}
@ -86,15 +92,17 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
return; /* woops, concurrently dropped; no permissions
* check */
/* Currently, we only allow plain tables to be locked */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE)
/* Currently, we only allow plain tables or views to be locked */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
errmsg("\"%s\" is not a table or a view",
rv->relname)));
/* Check permissions. */
aclresult = LockTableAclCheck(relid, lockmode);
aclresult = LockTableAclCheck(relid, lockmode, GetUserId());
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
}
@ -107,7 +115,7 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
* multiply-inheriting children more than once, but that's no problem.
*/
static void
LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait)
LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, Oid userid)
{
List *children;
ListCell *lc;
@ -120,7 +128,7 @@ LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait)
AclResult aclresult;
/* Check permissions before acquiring the lock. */
aclresult = LockTableAclCheck(childreloid, lockmode);
aclresult = LockTableAclCheck(childreloid, lockmode, userid);
if (aclresult != ACLCHECK_OK)
{
char *relname = get_rel_name(childreloid);
@ -157,15 +165,120 @@ LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait)
continue;
}
LockTableRecurse(childreloid, lockmode, nowait);
LockTableRecurse(childreloid, lockmode, nowait, userid);
}
}
/*
* Apply LOCK TABLE recursively over a view
*
* All tables and views appearing in the view definition query are locked
* recursively with the same lock mode.
*/
typedef struct
{
Oid root_reloid;
LOCKMODE lockmode;
bool nowait;
Oid viewowner;
Oid viewoid;
} LockViewRecurse_context;
static bool
LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
ListCell *rtable;
foreach(rtable, query->rtable)
{
RangeTblEntry *rte = lfirst(rtable);
AclResult aclresult;
Oid relid = rte->relid;
char relkind = rte->relkind;
char *relname = get_rel_name(relid);
/* The OLD and NEW placeholder entries in the view's rtable are skipped. */
if (relid == context->viewoid &&
(!strcmp(rte->eref->aliasname, "old") || !strcmp(rte->eref->aliasname, "new")))
continue;
/* Currently, we only allow plain tables or views to be locked. */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
relkind != RELKIND_VIEW)
continue;
/* Check infinite recursion in the view definition. */
if (relid == context->root_reloid)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("infinite recursion detected in rules for relation \"%s\"",
get_rel_name(context->root_reloid))));
/* Check permissions with the view owner's privilege. */
aclresult = LockTableAclCheck(relid, context->lockmode, context->viewowner);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(relkind), relname);
/* We have enough rights to lock the relation; do so. */
if (!context->nowait)
LockRelationOid(relid, context->lockmode);
else if (!ConditionalLockRelationOid(relid, context->lockmode))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on relation \"%s\"",
relname)));
if (relkind == RELKIND_VIEW)
LockViewRecurse(relid, context->root_reloid, context->lockmode, context->nowait);
else if (rte->inh)
LockTableRecurse(relid, context->lockmode, context->nowait, context->viewowner);
}
return query_tree_walker(query,
LockViewRecurse_walker,
context,
QTW_IGNORE_JOINALIASES);
}
return expression_tree_walker(node,
LockViewRecurse_walker,
context);
}
static void
LockViewRecurse(Oid reloid, Oid root_reloid, LOCKMODE lockmode, bool nowait)
{
LockViewRecurse_context context;
Relation view;
Query *viewquery;
view = heap_open(reloid, NoLock);
viewquery = get_view_query(view);
heap_close(view, NoLock);
context.root_reloid = root_reloid;
context.lockmode = lockmode;
context.nowait = nowait;
context.viewowner = view->rd_rel->relowner;
context.viewoid = reloid;
LockViewRecurse_walker((Node *) viewquery, &context);
}
/*
* Check whether the current user is permitted to lock this relation.
*/
static AclResult
LockTableAclCheck(Oid reloid, LOCKMODE lockmode)
LockTableAclCheck(Oid reloid, LOCKMODE lockmode, Oid userid)
{
AclResult aclresult;
AclMode aclmask;
@ -178,7 +291,7 @@ LockTableAclCheck(Oid reloid, LOCKMODE lockmode)
else
aclmask = ACL_UPDATE | ACL_DELETE | ACL_TRUNCATE;
aclresult = pg_class_aclcheck(reloid, GetUserId(), aclmask);
aclresult = pg_class_aclcheck(reloid, userid, aclmask);
return aclresult;
}

100
src/test/regress/expected/lock.out
View File

@ -5,7 +5,13 @@
CREATE SCHEMA lock_schema1;
SET search_path = lock_schema1;
CREATE TABLE lock_tbl1 (a BIGINT);
CREATE VIEW lock_view1 AS SELECT 1;
CREATE TABLE lock_tbl1a (a BIGINT);
CREATE VIEW lock_view1 AS SELECT * FROM lock_tbl1;
CREATE VIEW lock_view2(a,b) AS SELECT * FROM lock_tbl1, lock_tbl1a;
CREATE VIEW lock_view3 AS SELECT * from lock_view2;
CREATE VIEW lock_view4 AS SELECT (select a from lock_tbl1a limit 1) from lock_tbl1;
CREATE VIEW lock_view5 AS SELECT * from lock_tbl1 where a in (select * from lock_tbl1a);
CREATE VIEW lock_view6 AS SELECT * from (select * from lock_tbl1) sub;
CREATE ROLE regress_rol_lock1;
ALTER ROLE regress_rol_lock1 SET search_path = lock_schema1;
GRANT USAGE ON SCHEMA lock_schema1 TO regress_rol_lock1;
@ -30,8 +36,90 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN SHARE ROW EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN ACCESS EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_view1 IN EXCLUSIVE MODE; -- Will fail; can't lock a non-table
ERROR: "lock_view1" is not a table
ROLLBACK;
-- Verify that we can lock views.
BEGIN TRANSACTION;
LOCK TABLE lock_view1 IN EXCLUSIVE MODE;
-- lock_view1 and lock_tbl1 are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_view1
(2 rows)
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view2 IN EXCLUSIVE MODE;
-- lock_view1, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_tbl1a
lock_view2
(3 rows)
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view3 IN EXCLUSIVE MODE;
-- lock_view3, lock_view2, lock_tbl1, and lock_tbl1a are locked recursively.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_tbl1a
lock_view2
lock_view3
(4 rows)
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view4 IN EXCLUSIVE MODE;
-- lock_view4, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_tbl1a
lock_view4
(3 rows)
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view5 IN EXCLUSIVE MODE;
-- lock_view5, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_tbl1a
lock_view5
(3 rows)
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view6 IN EXCLUSIVE MODE;
-- lock_view6 an lock_tbl1 are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
relname
------------
lock_tbl1
lock_view6
(2 rows)
ROLLBACK;
-- Verify that we can lock a table with inheritance children.
CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);
@ -54,10 +142,16 @@ RESET ROLE;
--
-- Clean up
--
DROP VIEW lock_view6;
DROP VIEW lock_view5;
DROP VIEW lock_view4;
DROP VIEW lock_view3;
DROP VIEW lock_view2;
DROP VIEW lock_view1;
DROP TABLE lock_tbl3;
DROP TABLE lock_tbl2;
DROP TABLE lock_tbl1;
DROP TABLE lock_tbl1a;
DROP SCHEMA lock_schema1 CASCADE;
DROP ROLE regress_rol_lock1;
-- atomic ops tests

59
src/test/regress/sql/lock.sql
View File

@ -6,7 +6,13 @@
CREATE SCHEMA lock_schema1;
SET search_path = lock_schema1;
CREATE TABLE lock_tbl1 (a BIGINT);
CREATE VIEW lock_view1 AS SELECT 1;
CREATE TABLE lock_tbl1a (a BIGINT);
CREATE VIEW lock_view1 AS SELECT * FROM lock_tbl1;
CREATE VIEW lock_view2(a,b) AS SELECT * FROM lock_tbl1, lock_tbl1a;
CREATE VIEW lock_view3 AS SELECT * from lock_view2;
CREATE VIEW lock_view4 AS SELECT (select a from lock_tbl1a limit 1) from lock_tbl1;
CREATE VIEW lock_view5 AS SELECT * from lock_tbl1 where a in (select * from lock_tbl1a);
CREATE VIEW lock_view6 AS SELECT * from (select * from lock_tbl1) sub;
CREATE ROLE regress_rol_lock1;
ALTER ROLE regress_rol_lock1 SET search_path = lock_schema1;
GRANT USAGE ON SCHEMA lock_schema1 TO regress_rol_lock1;
@ -33,7 +39,50 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN SHARE ROW EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_tbl1 IN ACCESS EXCLUSIVE MODE NOWAIT;
LOCK TABLE lock_view1 IN EXCLUSIVE MODE; -- Will fail; can't lock a non-table
ROLLBACK;
-- Verify that we can lock views.
BEGIN TRANSACTION;
LOCK TABLE lock_view1 IN EXCLUSIVE MODE;
-- lock_view1 and lock_tbl1 are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view2 IN EXCLUSIVE MODE;
-- lock_view1, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view3 IN EXCLUSIVE MODE;
-- lock_view3, lock_view2, lock_tbl1, and lock_tbl1a are locked recursively.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view4 IN EXCLUSIVE MODE;
-- lock_view4, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view5 IN EXCLUSIVE MODE;
-- lock_view5, lock_tbl1, and lock_tbl1a are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
BEGIN TRANSACTION;
LOCK TABLE lock_view6 IN EXCLUSIVE MODE;
-- lock_view6 an lock_tbl1 are locked.
select relname from pg_locks l, pg_class c
where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
order by relname;
ROLLBACK;
-- Verify that we can lock a table with inheritance children.
@ -58,10 +107,16 @@ RESET ROLE;
--
-- Clean up
--
DROP VIEW lock_view6;
DROP VIEW lock_view5;
DROP VIEW lock_view4;
DROP VIEW lock_view3;
DROP VIEW lock_view2;
DROP VIEW lock_view1;
DROP TABLE lock_tbl3;
DROP TABLE lock_tbl2;
DROP TABLE lock_tbl1;
DROP TABLE lock_tbl1a;
DROP SCHEMA lock_schema1 CASCADE;
DROP ROLE regress_rol_lock1;