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author | Fujii Masao | 2015-09-11 04:02:15 +0000 |
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committer | Fujii Masao | 2015-09-11 04:02:15 +0000 |
commit | a1b28885177aff123cafe5a7f694555af33ad4e9 (patch) | |
tree | 28f2154f4bed6dff179d4cca14e6d787e1a950d3 /doc/src/sgml/storage.sgml | |
parent | 103ef2021110e66c2b3b87af4b0a901683b0275e (diff) |
Correct description of PageHeaderData layout in documentation
Back-patch to 9.3 where PageHeaderData layout was changed.
Michael Paquier
Diffstat (limited to 'doc/src/sgml/storage.sgml')
-rw-r--r-- | doc/src/sgml/storage.sgml | 26 |
1 files 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> |