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authorTom Lane2007-09-29 01:36:29 +0000
committerTom Lane2007-09-29 01:36:29 +0000
commit9618af7b2709f3a99c929de6854ad8c5964527d7 (patch)
treeeac137b1721537d8234128006412716bb112aa93 /doc/src
parentbc16ca2746648df49f9f35ee3818aa3c5e84b095 (diff)
Make archive recovery always start a new timeline, rather than only when a
recovery stop time was used. This avoids a corner-case risk of trying to overwrite an existing archived copy of the last WAL segment, and seems simpler and cleaner all around than the original definition. Per example from Jon Colverson and subsequent analysis by Simon.
Diffstat (limited to 'doc/src')
-rw-r--r--doc/src/sgml/backup.sgml10
1 files changed, 4 insertions, 6 deletions
diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index e8f093d4f01..770bec6df55 100644
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.75.2.2 2006/11/04 18:20:40 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.75.2.3 2007/09/29 01:36:29 tgl Exp $
-->
<chapter id="backup">
<title>Backup and Restore</title>
@@ -1084,11 +1084,9 @@ restore_command = 'copy /mnt/server/archivedir/%f "%p"' # Windows
<para>
To deal with these problems, <productname>PostgreSQL</> has a notion
- of <firstterm>timelines</>. Each time you recover to a point-in-time
- earlier than the end of the WAL sequence, a new timeline is created
- to identify the series of WAL records generated after that recovery.
- (If recovery proceeds all the way to the end of WAL, however, we do not
- start a new timeline: we just extend the existing one.) The timeline
+ of <firstterm>timelines</>. Whenever an archive recovery is completed,
+ a new timeline is created to identify the series of WAL records
+ generated after that recovery. The timeline
ID number is part of WAL segment file names, and so a new timeline does
not overwrite the WAL data generated by previous timelines. It is
in fact possible to archive many different timelines. While that might