Commit4b113d9

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Document that archive_timeout will force new WAL files even if a single

checkpoint has happened, and recommend adjusting checkpoint_timeout toreduce the impact of this.

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+11

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Lines changed: 6 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.249 2010/02/03 17:25:05 momjian Exp $ -->`
	`1`	`+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.250 2010/02/05 23:37:43 momjian Exp $ -->`
`2`	`2`
`3`	`3`	`<chapter Id="runtime-config">`
`4`	`4`	`<title>Server Configuration</title>`
`@@ -1739,7 +1739,11 @@ archive_command = 'copy "%p" "C:\\server\\archivedir\\%f"' # Windows`
`1739`	`1739`	`server to switch to a new WAL segment file periodically. When this`
`1740`	`1740`	`parameter is greater than zero, the server will switch to a new`
`1741`	`1741`	`segment file whenever this many seconds have elapsed since the last`
`1742`		`- segment file switch. Note that archived files that are closed early`
	`1742`	`+ segment file switch, and there has been any database activity,`
	`1743`	`+ including a single checkpoint. (Increasing`
	`1744`	`+ <varname>checkpoint_timeout</> will reduce unnecessary`
	`1745`	`+ checkpoints on an idle system.)`
	`1746`	`+ Note that archived files that are closed early`
`1743`	`1747`	`due to a forced switch are still the same length as completely full`
`1744`	`1748`	`files. Therefore, it is unwise to use a very short`
`1745`	`1749`	`<varname>archive_timeout</> — it will bloat your archive`

Lines changed: 5 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -38,7 +38,7 @@`
`38`	`38`	`*`
`39`	`39`	`*`
`40`	`40`	`* IDENTIFICATION`
`41`		`- * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.66 2010/01/15 09:19:02 heikki Exp $`
	`41`	`+ * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.67 2010/02/05 23:37:43 momjian Exp $`
`42`	`42`	`*`
`43`	`43`	`*-------------------------------------------------------------------------`
`44`	`44`	`*/`
`@@ -543,7 +543,10 @@ BackgroundWriterMain(void)`
`543`	`543`
`544`	`544`	`/*`
`545`	`545`	`* CheckArchiveTimeout -- check for archive_timeout and switch xlog files`
`546`		`- *if needed`
	`546`	`+ *`
	`547`	`+ * This will switch to a new WAL file and force an archive file write`
	`548`	`+ * if any activity is recorded in the current WAL file, including just`
	`549`	`+ * a single checkpoint record.`
`547`	`550`	`*/`
`548`	`551`	`staticvoid`
`549`	`552`	`CheckArchiveTimeout(void)`

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