diff options
| -rw-r--r-- | src/backend/access/index/genam.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c index a79c3920713..5662bb01088 100644 --- a/src/backend/access/index/genam.c +++ b/src/backend/access/index/genam.c @@ -217,7 +217,16 @@ systable_beginscan(Relation heapRelation, } else { - sysscan->scan = heap_beginscan(heapRelation, snapshot, nkeys, key); + /* + * We disallow synchronized scans when forced to use a heapscan on a + * catalog. In most cases the desired rows are near the front, so + * that the unpredictable start point of a syncscan is a serious + * disadvantage; and there are no compensating advantages, because + * it's unlikely that such scans will occur in parallel. + */ + sysscan->scan = heap_beginscan_strat(heapRelation, snapshot, + nkeys, key, + true, false); sysscan->iscan = NULL; } |