diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/catalog/index.c | 64 |
1 files changed, 51 insertions, 13 deletions
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 203d3f1ef80..65ec5ad42cf 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.95 1999/11/16 04:13:55 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.96 1999/11/21 20:01:10 tgl Exp $ * * * INTERFACE ROUTINES @@ -72,6 +72,7 @@ static void DefaultBuild(Relation heapRelation, Relation indexRelation, int numberOfAttributes, AttrNumber *attributeNumber, IndexStrategy indexStrategy, uint16 parameterCount, Datum *parameter, FuncIndexInfoPtr funcInfo, PredInfo *predInfo); +static Oid IndexGetRelation(Oid indexId); /* ---------------------------------------------------------------- * sysatts is a structure containing attribute tuple forms @@ -1109,7 +1110,8 @@ index_create(char *heapRelationName, void index_destroy(Oid indexId) { - Relation userindexRelation; + Relation userHeapRelation; + Relation userIndexRelation; Relation indexRelation; Relation relationRelation; Relation attributeRelation; @@ -1118,12 +1120,21 @@ index_destroy(Oid indexId) Assert(OidIsValid(indexId)); - userindexRelation = index_open(indexId); - - /* - * Get exclusive lock to ensure no one else is scanning this index. + /* ---------------- + * To drop an index safely, we must grab exclusive lock on its parent + * table; otherwise there could be other backends using the index! + * Exclusive lock on the index alone is insufficient because the index + * access routines are a little slipshod about obtaining adequate locking + * (see ExecOpenIndices()). 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. + * ---------------- */ - LockRelation(userindexRelation, AccessExclusiveLock); + userHeapRelation = heap_open(IndexGetRelation(indexId), + AccessExclusiveLock); + + userIndexRelation = index_open(indexId); + LockRelation(userIndexRelation, AccessExclusiveLock); /* ---------------- * DROP INDEX within a transaction block is dangerous, because @@ -1137,14 +1148,13 @@ index_destroy(Oid indexId) * they don't exist anyway. So, no warning in that case. * ---------------- */ - if (IsTransactionBlock() && ! userindexRelation->rd_myxactonly) + if (IsTransactionBlock() && ! userIndexRelation->rd_myxactonly) elog(NOTICE, "Caution: DROP INDEX cannot be rolled back, so don't abort now"); /* ---------------- * fix DESCRIPTION relation * ---------------- */ - DeleteComments(indexId); /* ---------------- @@ -1198,14 +1208,18 @@ index_destroy(Oid indexId) heap_close(indexRelation, RowExclusiveLock); /* - * flush cache and physically remove the file + * flush buffer cache and physically remove the file */ - ReleaseRelationBuffers(userindexRelation); + ReleaseRelationBuffers(userIndexRelation); - if (smgrunlink(DEFAULT_SMGR, userindexRelation) != SM_SUCCESS) + if (smgrunlink(DEFAULT_SMGR, userIndexRelation) != SM_SUCCESS) elog(ERROR, "index_destroy: unlink: %m"); - index_close(userindexRelation); + /* + * Close rels, but keep locks + */ + index_close(userIndexRelation); + heap_close(userHeapRelation, NoLock); RelationForgetRelation(indexId); @@ -1721,6 +1735,30 @@ index_build(Relation heapRelation, } /* + * IndexGetRelation: given an index's relation OID, get the OID of the + * relation it is an index on. Uses the system cache. + */ +static Oid +IndexGetRelation(Oid indexId) +{ + HeapTuple tuple; + Form_pg_index index; + + tuple = SearchSysCacheTuple(INDEXRELID, + ObjectIdGetDatum(indexId), + 0, 0, 0); + if (!HeapTupleIsValid(tuple)) + { + elog(ERROR, "IndexGetRelation: can't find index id %u", + indexId); + } + index = (Form_pg_index) GETSTRUCT(tuple); + Assert(index->indexrelid == indexId); + + return index->indrelid; +} + +/* * IndexIsUnique: given an index's relation OID, see if it * is unique using the system cache. */ |