diff options
Diffstat (limited to 'src/backend/optimizer')
| -rw-r--r-- | src/backend/optimizer/util/plancat.c | 27 | ||||
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 4 |
2 files changed, 20 insertions, 11 deletions
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index ff453336a16..bafe1b66731 100644 --- a/src/backend/optimizer/util/plancat.c +++ b/src/backend/optimizer/util/plancat.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.121 2006/07/14 14:52:21 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.122 2006/07/31 20:09:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -64,7 +64,7 @@ static List *get_relation_constraints(Oid relationObjectId, RelOptInfo *rel); * widths here, and we may as well cache the results for costsize.c. */ void -get_relation_info(Oid relationObjectId, RelOptInfo *rel) +get_relation_info(PlannerInfo *root, Oid relationObjectId, RelOptInfo *rel) { Index varno = rel->relid; Relation relation; @@ -105,9 +105,23 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel) { List *indexoidlist; ListCell *l; + LOCKMODE lmode; indexoidlist = RelationGetIndexList(relation); + /* + * For each index, we get the same type of lock that the executor will + * need, and do not release it. This saves a couple of trips to the + * shared lock manager while not creating any real loss of + * concurrency, because no schema changes could be happening on the + * index while we hold lock on the parent rel, and neither lock type + * blocks any other kind of index operation. + */ + if (rel->relid == root->parse->resultRelation) + lmode = RowExclusiveLock; + else + lmode = AccessShareLock; + foreach(l, indexoidlist) { Oid indexoid = lfirst_oid(l); @@ -120,13 +134,8 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel) /* * Extract info from the relation descriptor for the index. - * - * Note that we take no lock on the index; we assume our lock on - * the parent table will protect the index's schema information. - * When and if the executor actually uses the index, it will take - * a lock as needed to protect the access to the index contents. */ - indexRelation = index_open(indexoid); + indexRelation = index_open(indexoid, lmode); index = indexRelation->rd_index; info = makeNode(IndexOptInfo); @@ -203,7 +212,7 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel) info->tuples = rel->tuples; } - index_close(indexRelation); + index_close(indexRelation, NoLock); indexinfos = lcons(info, indexinfos); } diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index d20a8154612..8d06254a9f4 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.79 2006/07/14 14:52:21 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.80 2006/07/31 20:09:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -92,7 +92,7 @@ build_simple_rel(PlannerInfo *root, int relid, RelOptKind reloptkind) { case RTE_RELATION: /* Table --- retrieve statistics from the system catalogs */ - get_relation_info(rte->relid, rel); + get_relation_info(root, rte->relid, rel); break; case RTE_SUBQUERY: case RTE_FUNCTION: |