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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-09-02 19:02:20 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-09-02 19:02:20 +0000 |
| commit | 35e9b1cc1ee296959d52383455052cb3743af478 (patch) | |
| tree | 760d8047d591cd1e96316b3a9c12764a12dc6ae3 /src/backend/commands/vacuumlazy.c | |
| parent | 962a4bb69f1dd70f1212e27ba2de7634cf91a80d (diff) | |
| download | postgresql-35e9b1cc1ee296959d52383455052cb3743af478.tar.gz | |
Clean up a couple of ad-hoc computations of the maximum number of tuples
on a page, as suggested by ITAGAKI Takahiro. Also, change a few places
that were using some other estimates of max-items-per-page to consistently
use MaxOffsetNumber. This is conservatively large --- we could have used
the new MaxHeapTuplesPerPage macro, or a similar one for index tuples ---
but those places are simply declaring a fixed-size buffer and assuming it
will work, rather than actively testing for overrun. It seems safer to
size these buffers in a way that can't overflow even if the page is
corrupt.
Diffstat (limited to 'src/backend/commands/vacuumlazy.c')
| -rw-r--r-- | src/backend/commands/vacuumlazy.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c index bfdf4b6cbb..f324b72673 100644 --- a/src/backend/commands/vacuumlazy.c +++ b/src/backend/commands/vacuumlazy.c @@ -31,7 +31,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.57 2005/08/20 23:26:13 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.58 2005/09/02 19:02:20 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -60,9 +60,6 @@ #define REL_TRUNCATE_MINIMUM 1000 #define REL_TRUNCATE_FRACTION 16 -/* MAX_TUPLES_PER_PAGE can be a conservative upper limit */ -#define MAX_TUPLES_PER_PAGE ((int) (BLCKSZ / sizeof(HeapTupleHeaderData))) - typedef struct LVRelStats { @@ -259,7 +256,7 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, * dead-tuple TIDs, pause and do a cycle of vacuuming before we * tackle this page. */ - if ((vacrelstats->max_dead_tuples - vacrelstats->num_dead_tuples) < MAX_TUPLES_PER_PAGE && + if ((vacrelstats->max_dead_tuples - vacrelstats->num_dead_tuples) < MaxHeapTuplesPerPage && vacrelstats->num_dead_tuples > 0) { /* Remove index entries */ @@ -554,7 +551,7 @@ static int lazy_vacuum_page(Relation onerel, BlockNumber blkno, Buffer buffer, int tupindex, LVRelStats *vacrelstats) { - OffsetNumber unused[BLCKSZ / sizeof(OffsetNumber)]; + OffsetNumber unused[MaxOffsetNumber]; int uncnt; Page page = BufferGetPage(buffer); ItemId itemid; @@ -960,7 +957,7 @@ lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks) maxtuples = (maintenance_work_mem * 1024L) / sizeof(ItemPointerData); maxtuples = Min(maxtuples, INT_MAX); /* stay sane if small maintenance_work_mem */ - maxtuples = Max(maxtuples, MAX_TUPLES_PER_PAGE); + maxtuples = Max(maxtuples, MaxHeapTuplesPerPage); vacrelstats->num_dead_tuples = 0; vacrelstats->max_dead_tuples = (int) maxtuples; |