diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-30 20:12:03 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-30 20:12:03 +0000 |
| commit | d526575f893c1a4e05ebd307e80203536b213a6d (patch) | |
| tree | 529be7e5571f622bad1daab0d02de0c6669e9b81 /src/backend/tcop/utility.c | |
| parent | 0a6f2ee84de589e14941da640fb686c7eda7be01 (diff) | |
Make large sequential scans and VACUUMs work in a limited-size "ring" of
buffers, rather than blowing out the whole shared-buffer arena. Aside from
avoiding cache spoliation, this fixes the problem that VACUUM formerly tended
to cause a WAL flush for every page it modified, because we had it hacked to
use only a single buffer. Those flushes will now occur only once per
ring-ful. The exact ring size, and the threshold for seqscans to switch into
the ring usage pattern, remain under debate; but the infrastructure seems
done. The key bit of infrastructure is a new optional BufferAccessStrategy
object that can be passed to ReadBuffer operations; this replaces the former
StrategyHintVacuum API.
This patch also changes the buffer usage-count methodology a bit: we now
advance usage_count when first pinning a buffer, rather than when last
unpinning it. To preserve the behavior that a buffer's lifetime starts to
decrease when it's released, the clock sweep code is modified to not decrement
usage_count of pinned buffers.
Work not done in this commit: teach GiST and GIN indexes to use the vacuum
BufferAccessStrategy for vacuum-driven fetches.
Original patch by Simon, reworked by Heikki and again by Tom.
Diffstat (limited to 'src/backend/tcop/utility.c')
| -rw-r--r-- | src/backend/tcop/utility.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c index 028cb47c7ac..baa203a2d19 100644 --- a/src/backend/tcop/utility.c +++ b/src/backend/tcop/utility.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.279 2007/04/27 22:05:49 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.280 2007/05/30 20:12:01 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -931,7 +931,7 @@ ProcessUtility(Node *parsetree, break; case T_VacuumStmt: - vacuum((VacuumStmt *) parsetree, NIL, isTopLevel); + vacuum((VacuumStmt *) parsetree, NIL, NULL, isTopLevel); break; case T_ExplainStmt: |