database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-13 07:41:39 +03:00
Code Activity

Improve handling of prune/no-prune decisions by storing a page's oldest

Browse Source 
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.
This commit is contained in:
Tom Lane
2007-09-21 21:25:42 +00:00
parent 386a5d4268
commit cc59049daf
10 changed files with 92 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/backend/access/heap/heapam.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.241 2007/09/20 17:56:30 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.242 2007/09/21 21:25:42 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -2068,11 +2068,12 @@ l1:
/*
* If this transaction commits, the tuple will become DEAD sooner or
* later. Set hint bit that this page is a candidate for pruning. If
* the transaction finally aborts, the subsequent page pruning will be
* a no-op and the hint will be cleared.
* later. Set flag that this page is a candidate for pruning once our xid
* falls below the OldestXmin horizon. If the transaction finally aborts,
* the subsequent page pruning will be a no-op and the hint will be
* cleared.
*/
PageSetPrunable((Page) dp);
PageSetPrunable(dp, xid);
/* store transaction information of xact deleting the tuple */
tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
@ -2571,16 +2572,17 @@ l2:
/*
* If this transaction commits, the old tuple will become DEAD sooner or
* later. Set hint bit that this page is a candidate for pruning. If
* the transaction finally aborts, the subsequent page pruning will be
* a no-op and the hint will be cleared.
* later. Set flag that this page is a candidate for pruning once our xid
* falls below the OldestXmin horizon. If the transaction finally aborts,
* the subsequent page pruning will be a no-op and the hint will be
* cleared.
*
* XXX Should we set hint on newbuf as well? If the transaction
* aborts, there would be a prunable tuple in the newbuf; but for now
* we choose not to optimize for aborts. Note that heap_xlog_update
* must be kept in sync if this changes.
* must be kept in sync if this decision changes.
*/
PageSetPrunable(dp);
PageSetPrunable(dp, xid);
if (use_hot_update)
{
@ -4108,7 +4110,7 @@ heap_xlog_delete(XLogRecPtr lsn, XLogRecord *record)
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
/* Mark the page as a candidate for pruning */
PageSetPrunable(page);
PageSetPrunable(page, record->xl_xid);
/* Make sure there is no forward chain link in t_ctid */
htup->t_ctid = xlrec->target.tid;
@ -4284,7 +4286,7 @@ heap_xlog_update(XLogRecPtr lsn, XLogRecord *record, bool move, bool hot_update)
}
/* Mark the page as a candidate for pruning */
PageSetPrunable(page);
PageSetPrunable(page, record->xl_xid);
/*
* this test is ugly, but necessary to avoid thinking that insert change