From a1b28885177aff123cafe5a7f694555af33ad4e9 Mon Sep 17 00:00:00 2001
From: Fujii Masao <fujii@postgresql.org>
Date: Fri, 11 Sep 2015 13:02:15 +0900
Subject: [PATCH] Correct description of PageHeaderData layout in documentation
Back-patch to 9.3 where PageHeaderData layout was changed.
Michael Paquier
---
doc/src/sgml/storage.sgml | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index e5b7b4b68d0..0153b08073f 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -758,18 +758,18 @@ data. Empty in ordinary tables.</entry>
<para>
The first 24 bytes of each page consists of a page header
- (PageHeaderData). Its format is detailed in <xref
- linkend="pageheaderdata-table">. The first two fields track the most
- recent WAL entry related to this page. Next is a 2-byte field
- containing flag bits. This is followed by three 2-byte integer fields
- (<structfield>pd_lower</structfield>, <structfield>pd_upper</structfield>,
- and <structfield>pd_special</structfield>). These contain byte offsets
- from the page start to the start
- of unallocated space, to the end of unallocated space, and to the start of
- the special space.
- The next 2 bytes of the page header,
- <structfield>pd_pagesize_version</structfield>, store both the page size
- and a version indicator. Beginning with
+ (<structname>PageHeaderData</>). Its format is detailed in <xref
+ linkend="pageheaderdata-table">. The first field tracks the most
+ recent WAL entry related to this page. The second field contains
+ the page checksum if <xref linkend="app-initdb-data-checksums"> are
+ enabled. Next is a 2-byte field containing flag bits. This is followed
+ by three 2-byte integer fields (<structfield>pd_lower</structfield>,
+ <structfield>pd_upper</structfield>, and
+ <structfield>pd_special</structfield>). These contain byte offsets
+ from the page start to the start of unallocated space, to the end of
+ unallocated space, and to the start of the special space. The next 2
+ bytes of the page header, <structfield>pd_pagesize_version</structfield>,
+ store both the page size and a version indicator. Beginning with
<productname>PostgreSQL</productname> 8.3 the version number is 4;
<productname>PostgreSQL</productname> 8.1 and 8.2 used version number 3;
<productname>PostgreSQL</productname> 8.0 used version number 2;
@@ -799,7 +799,7 @@ data. Empty in ordinary tables.</entry>
<tbody>
<row>
<entry>pd_lsn</entry>
- <entry>XLogRecPtr</entry>
+ <entry>PageXLogRecPtr</entry>
<entry>8 bytes</entry>
<entry>LSN: next byte after last byte of xlog record for last change
to this page</entry>
--
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