diff options
Diffstat (limited to 'src/backend/commands')
| -rw-r--r-- | src/backend/commands/indexcmds.c | 42 |
1 files changed, 19 insertions, 23 deletions
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c index e96235c6f53..81246768bc9 100644 --- a/src/backend/commands/indexcmds.c +++ b/src/backend/commands/indexcmds.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.147 2006/08/25 04:06:48 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.148 2006/08/27 19:14:34 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -119,8 +119,11 @@ DefineIndex(RangeVar *heapRelation, Datum reloptions; IndexInfo *indexInfo; int numberOfAttributes; + List *old_xact_list; + ListCell *lc; uint32 ixcnt; LockRelId heaprelid; + LOCKTAG heaplocktag; Snapshot snapshot; Relation pg_index; HeapTuple indexTuple; @@ -466,33 +469,26 @@ DefineIndex(RangeVar *heapRelation, CommitTransactionCommand(); StartTransactionCommand(); - /* Establish transaction snapshot ... else GetLatestSnapshot complains */ - (void) GetTransactionSnapshot(); - /* * Now we must wait until no running transaction could have the table open - * with the old list of indexes. If we can take an exclusive lock then - * there are none now and anybody who opens it later will get the new - * index in their relcache entry. Alternatively, if our Xmin reaches our - * own (new) transaction then we know no transactions that started before - * the index was visible are left anyway. + * with the old list of indexes. To do this, inquire which xacts currently + * would conflict with ShareLock on the table -- ie, which ones have + * a lock that permits writing the table. Then wait for each of these + * xacts to commit or abort. Note we do not need to worry about xacts + * that open the table for writing after this point; they will see the + * new index when they open it. + * + * Note: GetLockConflicts() never reports our own xid, + * hence we need not check for that. */ - for (;;) - { - CHECK_FOR_INTERRUPTS(); + SET_LOCKTAG_RELATION(heaplocktag, heaprelid.dbId, heaprelid.relId); + old_xact_list = GetLockConflicts(&heaplocktag, ShareLock); - if (ConditionalLockRelationOid(relationId, ExclusiveLock)) - { - /* Release the lock right away to avoid blocking anyone */ - UnlockRelationOid(relationId, ExclusiveLock); - break; - } - - if (TransactionIdEquals(GetLatestSnapshot()->xmin, - GetTopTransactionId())) - break; + foreach(lc, old_xact_list) + { + TransactionId xid = lfirst_xid(lc); - pg_usleep(1000000L); /* 1 sec */ + XactLockTableWait(xid); } /* |