diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml index c02d2ef32157ed45270ddd58486adc2590c8d9ec..8cf1ee377c52ba5333899279787c070ce635847a 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 2.61 2005/04/17 03:05:19 momjian Exp $ +$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.62 2005/04/18 01:29:00 momjian Exp $ --> <chapter id="backup"> <title>Backup and Restore</title> @@ -724,23 +724,32 @@ SELECT pg_stop_backup(); <para> To make use of this backup, you will need to keep around all the WAL - segment files generated at or after the starting time of the backup. + segment files generated during and after the file system backup. To aid you in doing this, the <function>pg_stop_backup</> function - creates a <firstterm>backup history file</> that is immediately stored - into the WAL archive area. This file is named after the first WAL - segment file that you need to have to make use of the backup. For - example, if the starting WAL file is <literal>0000000100001234000055CD</> - the backup history file will be named something like - <literal>0000000100001234000055CD.007C9330.backup</>. (The second part of - this file name stands for an exact position within the WAL file, and can - ordinarily be ignored.) Once you have safely archived this WAL - segment file, you can delete all archived WAL segments with names numerically - preceding this one. The backup history file is just a small text file. - It contains the label string you gave to <function>pg_start_backup</>, as - well as the starting and ending times of the backup. If you used the - label to identify where the associated dump file is kept, then the - archived history file is enough to tell you which dump file to restore, - should you need to do so. + creates a <firstterm>backup history file</> that is immediately + stored into the WAL archive area. This file is named after the first + WAL segment file that you need to have to make use of the backup. + For example, if the starting WAL file is + <literal>0000000100001234000055CD</> the backup history file will be + named something like + <literal>0000000100001234000055CD.007C9330.backup</>. (The second + number in the file name stands for an exact position within the WAL + file, and can ordinarily be ignored.) Once you have safely archived + the WAL segment files used during the file system backup (as + specified in the backup history file), you can delete all archived + WAL segments with names numerically less. Keep in mind that only + completed WAL segment files are archived, so there will be delay + between running <function>pg_stop_backup</> and the archiving of + all WAL segment files needed to make the file system backup + consistent. + </para> + <para> + The backup history file is just a small text file. It contains the + label string you gave to <function>pg_start_backup</>, as well as + the starting and ending times of the backup. If you used the label + to identify where the associated dump file is kept, then the + archived history file is enough to tell you which dump file to + restore, should you need to do so. </para> <para>