diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index b947c11f7d8..450bb15ff8d 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -479,8 +479,6 @@ heapgettup(HeapScanDesc scan, if (valid) { - if (!scan->rs_relpredicatelocked) - PredicateLockTuple(scan->rs_rd, tuple, snapshot); LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK); return; } @@ -748,16 +746,12 @@ heapgettup_pagemode(HeapScanDesc scan, nkeys, key, valid); if (valid) { - if (!scan->rs_relpredicatelocked) - PredicateLockTuple(scan->rs_rd, tuple, scan->rs_snapshot); scan->rs_cindex = lineindex; return; } } else { - if (!scan->rs_relpredicatelocked) - PredicateLockTuple(scan->rs_rd, tuple, scan->rs_snapshot); scan->rs_cindex = lineindex; return; } @@ -1224,13 +1218,26 @@ heap_beginscan_internal(Relation relation, Snapshot snapshot, scan->rs_strategy = NULL; /* set in initscan */ scan->rs_allow_strat = allow_strat; scan->rs_allow_sync = allow_sync; - scan->rs_relpredicatelocked = false; /* * we can use page-at-a-time mode if it's an MVCC-safe snapshot */ scan->rs_pageatatime = IsMVCCSnapshot(snapshot); + /* + * For a seqscan in a serializable transaction, acquire a predicate lock + * on the entire relation. This is required not only to lock all the + * matching tuples, but also to conflict with new insertions into the + * table. In an indexscan, we take page locks on the index pages covering + * the range specified in the scan qual, but in a heap scan there is + * nothing more fine-grained to lock. A bitmap scan is a different story, + * there we have already scanned the index and locked the index pages + * covering the predicate. But in that case we still have to lock any + * matching heap tuples. + */ + if (!is_bitmapscan) + PredicateLockRelation(relation, snapshot); + /* we only need to set this up once */ scan->rs_ctup.t_tableOid = RelationGetRelid(relation); |