database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-02 09:02:37 +03:00
Code Activity

Reduce WAL activity for page splits:

Browse Source 
> Currently, an index split writes all the data on the split page to
> WAL. That's a lot of WAL traffic. The tuples that are copied to the
> right page need to be WAL logged, but the tuples that stay on the
> original page don't.

Heikki Linnakangas
This commit is contained in:
Bruce Momjian
2007-02-08 05:05:53 +00:00
parent fe03a5f4ae
commit b79575ce45
3 changed files with 285 additions and 189 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
src/include/access/nbtree.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.110 2007/02/05 04:22:18 tgl Exp $
* $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.111 2007/02/08 05:05:53 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -259,7 +259,8 @@ typedef struct xl_btree_insert
*
* Note: the four XLOG_BTREE_SPLIT xl_info codes all use this data record.
* The _L and _R variants indicate whether the inserted tuple went into the
* left or right split page (and thus, whether otherblk is the right or left
* left or right split page (and thus, whether newitemoff and the new item
* are stored or not.
* page of the split pair). The _ROOT variants indicate that we are splitting
* the root page, and thus that a newroot record rather than an insert or
* split record should follow. Note that a split record never carries a
@ -267,17 +268,21 @@ typedef struct xl_btree_insert
*/
typedef struct xl_btree_split
{
xl_btreetid target; /* inserted tuple id */
BlockNumber otherblk; /* second block participated in split: */
/* first one is stored in target' tid */
BlockNumber leftblk; /* prev/left block */
BlockNumber rightblk; /* next/right block */
uint32 level; /* tree level of page being split */
uint16 leftlen; /* len of left page items below */
/* LEFT AND RIGHT PAGES TUPLES FOLLOW AT THE END */
RelFileNode node;
BlockNumber leftsib; /* orig page / new left page */
BlockNumber rightsib; /* new right page */
OffsetNumber firstright; /* first item stored on right page */
BlockNumber rnext; /* next/right block pointer */
uint32 level; /* tree level of page being split */
/* BlockIdData downlink follows if level > 0 */
/* OffsetNumber newitemoff follows in the _L variants. */
/* New item follows in the _L variants */
/* RIGHT PAGES TUPLES FOLLOW AT THE END */
} xl_btree_split;
#define SizeOfBtreeSplit (offsetof(xl_btree_split, leftlen) + sizeof(uint16))
#define SizeOfBtreeSplit (offsetof(xl_btree_split, level) + sizeof(uint32))
/*
* This is what we need to know about delete of individual leaf index tuples.