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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-09-21 21:25:42 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-09-21 21:25:42 +0000 |
| commit | cc59049daf78c3d351c1ec78fb319b5fdeb20d53 (patch) | |
| tree | 74c6471e902926264b639164859c2ae69a3420ed /src/backend/storage/page/bufpage.c | |
| parent | 386a5d4268c7ae13510f0a40243b2277eccb6189 (diff) | |
| download | postgresql-cc59049daf78c3d351c1ec78fb319b5fdeb20d53.tar.gz postgresql-cc59049daf78c3d351c1ec78fb319b5fdeb20d53.zip | |
Improve handling of prune/no-prune decisions by storing a page's oldest
unpruned XMAX in its header. At the cost of 4 bytes per page, this keeps us
from performing heap_page_prune when there's no chance of pruning anything.
Seems to be necessary per Heikki's preliminary performance testing.
Diffstat (limited to 'src/backend/storage/page/bufpage.c')
| -rw-r--r-- | src/backend/storage/page/bufpage.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c index b382e4d0240..ca5ea020747 100644 --- a/src/backend/storage/page/bufpage.c +++ b/src/backend/storage/page/bufpage.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.74 2007/09/20 17:56:31 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.75 2007/09/21 21:25:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -40,11 +40,12 @@ PageInit(Page page, Size pageSize, Size specialSize) /* Make sure all fields of page are zero, as well as unused space */ MemSet(p, 0, pageSize); - /* p->pd_flags = 0; done by above MemSet */ + /* p->pd_flags = 0; done by above MemSet */ p->pd_lower = SizeOfPageHeaderData; p->pd_upper = pageSize - specialSize; p->pd_special = pageSize - specialSize; PageSetPageSizeAndVersion(page, pageSize, PG_PAGE_LAYOUT_VERSION); + /* p->pd_prune_xid = InvalidTransactionId; done by above MemSet */ } |