diff options
| -rw-r--r-- | src/backend/catalog/index.c | 36 | ||||
| -rw-r--r-- | src/backend/optimizer/util/plancat.c | 11 |
2 files changed, 23 insertions, 24 deletions
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index cace4852d51..8fb2f8f4f22 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.239 2004/08/31 17:10:36 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.240 2004/10/01 17:11:49 tgl Exp $ * * * INTERFACE ROUTINES @@ -777,7 +777,7 @@ index_drop(Oid indexId) * backend might be in the midst of devising a query plan that will * use the index. The parser and planner take care to hold an * appropriate lock on the parent table while working, but having them - * hold locks on all the indexes too seems overly complex. We do grab + * hold locks on all the indexes too seems overly expensive. We do grab * exclusive lock on the index too, just to be safe. Both locks must * be held till end of transaction, else other backends will still see * this index in pg_index. @@ -1655,26 +1655,19 @@ reindex_index(Oid indexId) bool inplace; /* - * Open our index relation and get an exclusive lock on it. - * - * Note: for REINDEX INDEX, doing this before opening the parent heap - * relation means there's a possibility for deadlock failure against - * another xact that is doing normal accesses to the heap and index. - * However, it's not real clear why you'd be wanting to do REINDEX - * INDEX on a table that's in active use, so I'd rather have the - * protection of making sure the index is locked down. In the REINDEX - * TABLE and REINDEX DATABASE cases, there is no problem because - * caller already holds exclusive lock on the parent table. + * Open and lock the parent heap relation. ShareLock is sufficient + * since we only need to be sure no schema or data changes are going on. + */ + heapId = IndexGetRelation(indexId); + heapRelation = heap_open(heapId, ShareLock); + + /* + * Open the target index relation and get an exclusive lock on it, + * to ensure that no one else is touching this particular index. */ iRel = index_open(indexId); LockRelation(iRel, AccessExclusiveLock); - /* Get OID of index's parent table */ - heapId = iRel->rd_index->indrelid; - - /* Open and lock the parent heap relation */ - heapRelation = heap_open(heapId, AccessExclusiveLock); - /* * If it's a shared index, we must do inplace processing (because we * have no way to update relfilenode in other databases). Otherwise @@ -1759,11 +1752,10 @@ reindex_relation(Oid relid, bool toast_too) ListCell *indexId; /* - * Ensure to hold an exclusive lock throughout the transaction. The - * lock could perhaps be less intensive (in the non-overwrite case) - * but for now it's AccessExclusiveLock for simplicity. + * Open and lock the relation. ShareLock is sufficient since we only + * need to prevent schema and data changes in it. */ - rel = heap_open(relid, AccessExclusiveLock); + rel = heap_open(relid, ShareLock); toast_relid = rel->rd_rel->reltoastrelid; diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index ba58251919b..ed76fe8fb8c 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 1.96 2004/08/29 05:06:44 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.97 2004/10/01 17:11:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -90,7 +90,14 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel) int i; int16 amorderstrategy; - /* Extract info from the relation descriptor for the index */ + /* + * 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); index = indexRelation->rd_index; |