Commitfb8b38e

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Add a couple of notes pointing out that GIN index build time is very

sensitive to maintenance_work_mem (something I just learned the hardway).

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Lines changed: 14 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.12 2007/11/1323:36:26 tgl Exp $ -->`
	`1`	`+<!-- $PostgreSQL: pgsql/doc/src/sgml/gin.sgml,v 2.13 2007/11/16 03:23:07 tgl Exp $ -->`
`2`	`2`
`3`	`3`	`<chapter id="GIN">`
`4`	`4`	`<title>GIN Indexes</title>`
`@@ -161,6 +161,17 @@`
`161`	`161`	`</listitem>`
`162`	`162`	`</varlistentry>`
`163`	`163`
	`164`	`+ <varlistentry>`
	`165`	`+ <term><xref linkend="guc-maintenance-work-mem"></term>`
	`166`	`+ <listitem>`
	`167`	`+ <para>`
	`168`	`+ Build time for a <acronym>GIN</acronym> index is very sensitive to`
	`169`	`+ the <varname>maintenance_work_mem</> setting; it doesn't pay to`
	`170`	`+ skimp on work memory during index creation.`
	`171`	`+ </para>`
	`172`	`+ </listitem>`
	`173`	`+ </varlistentry>`
	`174`	`+`
`164`	`175`	`<varlistentry>`
`165`	`176`	`<term><xref linkend="guc-gin-fuzzy-search-limit"></term>`
`166`	`177`	`<listitem>`
`@@ -177,8 +188,8 @@`
`177`	`188`	`</para>`
`178`	`189`	`<para>`
`179`	`190`	`To facilitate controlled execution of such queries`
`180`		`- <acronym>GIN</acronym> has a configurable soft upper limit on the size`
`181`		`- ofthe returned set, the`
	`191`	`+ <acronym>GIN</acronym> has a configurable soft upper limit on the`
	`192`	`+numberofrows returned, the`
`182`	`193`	`<varname>gin_fuzzy_search_limit</varname> configuration parameter.`
`183`	`194`	`It is set to 0 (meaning no limit) by default.`
`184`	`195`	`If a non-zero limit is set, then the returned set is a subset of`

Lines changed: 8 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-<!-- $PostgreSQL: pgsql/doc/src/sgml/textsearch.sgml,v 1.35 2007/11/1423:48:55 tgl Exp $ -->`
	`1`	`+<!-- $PostgreSQL: pgsql/doc/src/sgml/textsearch.sgml,v 1.36 2007/11/16 03:23:07 tgl Exp $ -->`
`2`	`2`
`3`	`3`	`<chapter id="textsearch">`
`4`	`4`	`<title id="textsearch-title">Full Text Search</title>`
`@@ -3256,6 +3256,13 @@ EXPLAIN SELECT * FROM apod WHERE textsearch @@ to_tsquery('supernovae');`
`3256`	`3256`	`lexemes better but are slower to update.`
`3257`	`3257`	`</para>`
`3258`	`3258`
	`3259`	`+ <para>`
	`3260`	`+ Note that <acronym>GIN</acronym> index build time can often be improved`
	`3261`	`+ by increasing <xref linkend="guc-maintenance-work-mem">, while`
	`3262`	`+ <acronym>GiST</acronym> index build time is not sensitive to that`
	`3263`	`+ parameter.`
	`3264`	`+ </para>`
	`3265`	`+`
`3259`	`3266`	`<para>`
`3260`	`3267`	`Partitioning of big collections and the proper use of GiST and GIN indexes`
`3261`	`3268`	`allows the implementation of very fast searches with online update.`

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