Correct description of PageHeaderData layout in documentation

Back-patch to 9.3 where PageHeaderData layout was changed.

Michael Paquier

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 920b5f0dc3bc3b90fb19f672137ed0843052f8d8..8924b7483fc86e48c477311804116da44fc602db 100644 (file)
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -646,18 +646,18 @@ data. Empty in ordinary tables.
  
 
   The first 24 bytes of each page consists of a page header
-  (PageHeaderData). Its format is detailed in 
-  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
-  (pd_lower, pd_upper,
-  and pd_special). 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,
-  pd_pagesize_version, store both the page size
-  and a version indicator.  Beginning with
+  (PageHeaderData). Its format is detailed in 
+  linkend="pageheaderdata-table">. The first field tracks the most
+  recent WAL entry related to this page. The second field contains
+  the page checksum if  are
+  enabled.  Next is a 2-byte field containing flag bits. This is followed
+  by three 2-byte integer fields (pd_lower,
+  pd_upper, and
+  pd_special).  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, pd_pagesize_version,
+  store both the page size and a version indicator.  Beginning with
   PostgreSQL 8.3 the version number is 4;
   PostgreSQL 8.1 and 8.2 used version number 3;
   PostgreSQL 8.0 used version number 2;
@@ -687,7 +687,7 @@ data. Empty in ordinary tables.
  
   
    pd_lsn
-   XLogRecPtr
+   PageXLogRecPtr
    8 bytes
    LSN: next byte after last byte of xlog record for last change
    to this page