diff options
Diffstat (limited to 'src/backend/access/index/indexam.c')
| -rw-r--r-- | src/backend/access/index/indexam.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 949deb27a28..7c698fb48a2 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.74 2004/08/29 04:12:20 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.75 2004/09/30 23:21:14 tgl Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relation OID @@ -112,10 +112,15 @@ /* ---------------- * index_open - open an index relation by relation OID * - * Note: we acquire no lock on the index. An AccessShareLock is - * acquired by index_beginscan (and released by index_endscan). - * Generally, the caller should already hold some type of lock on - * the parent relation to ensure that the index doesn't disappear. + * Note: we acquire no lock on the index. A lock is not needed when + * simply examining the index reldesc; the index's schema information + * is considered to be protected by the lock that the caller had better + * be holding on the parent relation. Some type of lock should be + * obtained on the index before physically accessing it, however. + * This is handled automatically for most uses by index_beginscan + * and index_endscan for scan cases, or by ExecOpenIndices and + * ExecCloseIndices for update cases. Other callers will need to + * obtain their own locks. * * This is a convenience routine adapted for indexscan use. * Some callers may prefer to use relation_open directly. |