diff options
Diffstat (limited to 'src/backend/optimizer/prep/prepunion.c')
| -rw-r--r-- | src/backend/optimizer/prep/prepunion.c | 62 |
1 files changed, 31 insertions, 31 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c index a067ed36e69..09acdaca65e 100644 --- a/src/backend/optimizer/prep/prepunion.c +++ b/src/backend/optimizer/prep/prepunion.c @@ -22,7 +22,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.169 2009/05/12 00:56:05 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.170 2009/05/12 03:11:01 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -32,7 +32,7 @@ #include "access/heapam.h" #include "access/sysattr.h" #include "catalog/namespace.h" -#include "catalog/pg_inherits.h" +#include "catalog/pg_inherits_fn.h" #include "catalog/pg_type.h" #include "miscadmin.h" #include "nodes/makefuncs.h" @@ -1157,8 +1157,29 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti) return; } - /* Scan for all members of inheritance set */ - inhOIDs = find_all_inheritors(parentOID); + /* + * The rewriter should already have obtained an appropriate lock on each + * relation named in the query. However, for each child relation we add + * to the query, we must obtain an appropriate lock, because this will be + * the first use of those relations in the parse/rewrite/plan pipeline. + * + * If the parent relation is the query's result relation, then we need + * RowExclusiveLock. Otherwise, if it's accessed FOR UPDATE/SHARE, we + * need RowShareLock; otherwise AccessShareLock. We can't just grab + * AccessShareLock because then the executor would be trying to upgrade + * the lock, leading to possible deadlocks. (This code should match the + * parser and rewriter.) + */ + oldrc = get_rowmark(parse, rti); + if (rti == parse->resultRelation) + lockmode = RowExclusiveLock; + else if (oldrc) + lockmode = RowShareLock; + else + lockmode = AccessShareLock; + + /* Scan for all members of inheritance set, acquire needed locks */ + inhOIDs = find_all_inheritors(parentOID, lockmode); /* * Check that there's at least one descendant, else treat as no-child @@ -1173,40 +1194,19 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti) } /* - * Find out if parent relation is selected FOR UPDATE/SHARE. If so, - * we need to mark its RowMarkClause as isParent = true, and generate - * a new RowMarkClause for each child. + * If parent relation is selected FOR UPDATE/SHARE, we need to mark its + * RowMarkClause as isParent = true, and generate a new RowMarkClause for + * each child. */ - oldrc = get_rowmark(parse, rti); if (oldrc) oldrc->isParent = true; /* * Must open the parent relation to examine its tupdesc. We need not lock - * it since the rewriter already obtained at least AccessShareLock on each - * relation used in the query. + * it; we assume the rewriter already did. */ oldrelation = heap_open(parentOID, NoLock); - /* - * However, for each child relation we add to the query, we must obtain an - * appropriate lock, because this will be the first use of those relations - * in the parse/rewrite/plan pipeline. - * - * If the parent relation is the query's result relation, then we need - * RowExclusiveLock. Otherwise, if it's accessed FOR UPDATE/SHARE, we - * need RowShareLock; otherwise AccessShareLock. We can't just grab - * AccessShareLock because then the executor would be trying to upgrade - * the lock, leading to possible deadlocks. (This code should match the - * parser and rewriter.) - */ - if (rti == parse->resultRelation) - lockmode = RowExclusiveLock; - else if (oldrc) - lockmode = RowShareLock; - else - lockmode = AccessShareLock; - /* Scan the inheritance set and expand it */ appinfos = NIL; foreach(l, inhOIDs) @@ -1217,9 +1217,9 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti) Index childRTindex; AppendRelInfo *appinfo; - /* Open rel, acquire the appropriate lock type */ + /* Open rel if needed; we already have required locks */ if (childOID != parentOID) - newrelation = heap_open(childOID, lockmode); + newrelation = heap_open(childOID, NoLock); else newrelation = oldrelation; |