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Create an RTE field to record the query's lock mode for each relation.

Browse Source 
Add RangeTblEntry.rellockmode, which records the appropriate lock mode for
each RTE_RELATION rangetable entry (either AccessShareLock, RowShareLock,
or RowExclusiveLock depending on the RTE's role in the query).

This patch creates the field and makes all creators of RTE nodes fill it
in reasonably, but for the moment nothing much is done with it.  The plan
is to replace assorted post-parser logic that re-determines the right
lockmode to use with simple uses of rte->rellockmode.  For now, just add
Asserts in each of those places that the rellockmode matches what they are
computing today.  (In some cases the match isn't perfect, so the Asserts
are weaker than you might expect; but this seems OK, as per discussion.)

This passes check-world for me, but it seems worth pushing in this state
to see if the buildfarm finds any problems in cases I failed to test.

catversion bump due to change of stored rules.

Amit Langote, reviewed by David Rowley and Jesper Pedersen,
and whacked around a bit more by me

Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp
This commit is contained in:
Tom Lane
2018-09-30 13:55:51 -04:00
parent 8bddc86400
commit fdba460a26
29 changed files with 160 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
src/backend/commands/copy.c
View File

@ -833,20 +833,21 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
if (stmt->relation)
{
LOCKMODE lockmode = is_from ? RowExclusiveLock : AccessShareLock;
RangeTblEntry *rte;
TupleDesc tupDesc;
List *attnums;
ListCell *cur;
RangeTblEntry *rte;
Assert(!stmt->query);
/* Open and lock the relation, using the appropriate lock type. */
rel = heap_openrv(stmt->relation,
(is_from ? RowExclusiveLock : AccessShareLock));
rel = heap_openrv(stmt->relation, lockmode);
relid = RelationGetRelid(rel);
rte = addRangeTableEntryForRelation(pstate, rel, NULL, false, false);
rte = addRangeTableEntryForRelation(pstate, rel, lockmode,
NULL, false, false);
rte->requiredPerms = (is_from ? ACL_INSERT : ACL_SELECT);
tupDesc = RelationGetDescr(rel);

1
src/backend/commands/createas.c
View File

@ -528,6 +528,7 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
rte->rtekind = RTE_RELATION;
rte->relid = intoRelationAddr.objectId;
rte->relkind = relkind;
rte->rellockmode = RowExclusiveLock;
rte->requiredPerms = ACL_INSERT;
for (attnum = 1; attnum <= intoRelationDesc->rd_att->natts; attnum++)

23
src/backend/commands/policy.c
View File

@ -567,7 +567,9 @@ RemoveRoleFromObjectPolicy(Oid roleid, Oid classid, Oid policy_id)
qual_expr = stringToNode(qual_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
addRangeTableEntryForRelation(qual_pstate, rel, NULL, false, false);
addRangeTableEntryForRelation(qual_pstate, rel,
AccessShareLock,
NULL, false, false);
qual_parse_rtable = qual_pstate->p_rtable;
free_parsestate(qual_pstate);
@ -589,8 +591,9 @@ RemoveRoleFromObjectPolicy(Oid roleid, Oid classid, Oid policy_id)
with_check_qual = stringToNode(with_check_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
addRangeTableEntryForRelation(with_check_pstate, rel, NULL, false,
false);
addRangeTableEntryForRelation(with_check_pstate, rel,
AccessShareLock,
NULL, false, false);
with_check_parse_rtable = with_check_pstate->p_rtable;
free_parsestate(with_check_pstate);
@ -752,11 +755,13 @@ CreatePolicy(CreatePolicyStmt *stmt)
/* Add for the regular security quals */
rte = addRangeTableEntryForRelation(qual_pstate, target_table,
AccessShareLock,
NULL, false, false);
addRTEtoQuery(qual_pstate, rte, false, true, true);
/* Add for the with-check quals */
rte = addRangeTableEntryForRelation(with_check_pstate, target_table,
AccessShareLock,
NULL, false, false);
addRTEtoQuery(with_check_pstate, rte, false, true, true);
@ -928,6 +933,7 @@ AlterPolicy(AlterPolicyStmt *stmt)
ParseState *qual_pstate = make_parsestate(NULL);
rte = addRangeTableEntryForRelation(qual_pstate, target_table,
AccessShareLock,
NULL, false, false);
addRTEtoQuery(qual_pstate, rte, false, true, true);
@ -950,6 +956,7 @@ AlterPolicy(AlterPolicyStmt *stmt)
ParseState *with_check_pstate = make_parsestate(NULL);
rte = addRangeTableEntryForRelation(with_check_pstate, target_table,
AccessShareLock,
NULL, false, false);
addRTEtoQuery(with_check_pstate, rte, false, true, true);
@ -1096,8 +1103,9 @@ AlterPolicy(AlterPolicyStmt *stmt)
qual = stringToNode(qual_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
addRangeTableEntryForRelation(qual_pstate, target_table, NULL,
false, false);
addRangeTableEntryForRelation(qual_pstate, target_table,
AccessShareLock,
NULL, false, false);
qual_parse_rtable = qual_pstate->p_rtable;
free_parsestate(qual_pstate);
@ -1137,8 +1145,9 @@ AlterPolicy(AlterPolicyStmt *stmt)
with_check_qual = stringToNode(with_check_value);
/* Add this rel to the parsestate's rangetable, for dependencies */
addRangeTableEntryForRelation(with_check_pstate, target_table, NULL,
false, false);
addRangeTableEntryForRelation(with_check_pstate, target_table,
AccessShareLock,
NULL, false, false);
with_check_parse_rtable = with_check_pstate->p_rtable;
free_parsestate(with_check_pstate);

3
src/backend/commands/tablecmds.c
View File

@ -13632,7 +13632,8 @@ transformPartitionSpec(Relation rel, PartitionSpec *partspec, char *strategy)
* rangetable entry. We need a ParseState for transformExpr.
*/
pstate = make_parsestate(NULL);
rte = addRangeTableEntryForRelation(pstate, rel, NULL, false, true);
rte = addRangeTableEntryForRelation(pstate, rel, AccessShareLock,
NULL, false, true);
addRTEtoQuery(pstate, rte, true, true, true);
/* take care of any partition expressions */

2
src/backend/commands/trigger.c
View File

@ -577,10 +577,12 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString,
* 'OLD' must always have varno equal to 1 and 'NEW' equal to 2.
*/
rte = addRangeTableEntryForRelation(pstate, rel,
AccessShareLock,
makeAlias("old", NIL),
false, false);
addRTEtoQuery(pstate, rte, false, true, true);
rte = addRangeTableEntryForRelation(pstate, rel,
AccessShareLock,
makeAlias("new", NIL),
false, false);
addRTEtoQuery(pstate, rte, false, true, true);

4
src/backend/commands/view.c
View File

@ -353,7 +353,7 @@ DefineViewRules(Oid viewOid, Query *viewParse, bool replace)
* by 2...
*
* These extra RT entries are not actually used in the query,
* except for run-time permission checking.
* except for run-time locking and permission checking.
*---------------------------------------------------------------
*/
static Query *
@ -386,9 +386,11 @@ UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse)
* OLD first, then NEW....
*/
rt_entry1 = addRangeTableEntryForRelation(pstate, viewRel,
AccessShareLock,
makeAlias("old", NIL),
false, false);
rt_entry2 = addRangeTableEntryForRelation(pstate, viewRel,
AccessShareLock,
makeAlias("new", NIL),
false, false);
/* Must override addRangeTableEntry's default access-check flags */