From a04a423599b347325f9a73dfb2d533b24e1cbab3 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 8 Jun 2007 18:23:53 +0000 Subject: Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom. --- src/backend/storage/buffer/freelist.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'src/backend/storage/buffer/freelist.c') diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c index d8eec0f8231..a3e2c7c4422 100644 --- a/src/backend/storage/buffer/freelist.c +++ b/src/backend/storage/buffer/freelist.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.59 2007/05/30 20:11:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/storage/buffer/freelist.c,v 1.60 2007/06/08 18:23:52 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -340,6 +340,9 @@ GetAccessStrategy(BufferAccessStrategyType btype) * Select ring size to use. See buffer/README for rationales. * (Currently all cases are the same size, but keep this code * structure for flexibility.) + * + * Note: if you change the ring size for BAS_BULKREAD, see also + * SYNC_SCAN_REPORT_INTERVAL in access/heap/syncscan.c. */ switch (btype) { -- cgit v1.2.3