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help / color / mirror / Atom feedFrom: Bruce Momjian <[email protected]>
To: Jim C. Nasby <[email protected]>
Cc: [email protected]
Subject: Re: Lazy vacuum space reclaiming
Date: Wed, 7 Dec 2005 00:36:12 -0500 (EST)
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
Adjustment patch applied. Thanks.
---------------------------------------------------------------------------
Jim C. Nasby wrote:
> >From http://www.postgresql.org/docs/8.0/interactive/maintenance.html:
>
> "The first form, known as "lazy vacuum" or just VACUUM, marks expired
> data in tables and indexes for future reuse; it does not attempt to
> reclaim the space used by this expired data immediately. Therefore, the
> table file is not shortened, and any unused space in the file is not
> returned to the operating system."
>
> This isn't completely accurate, though I'm not sure what a good wording
> would be. Maybe:
>
> "The first form, known as "lazy vacuum" or just VACUUM, marks expired
> data in tables and indexes for future reuse. It only reclaims expired
> space from tables if it is at the end of the table, and no empty space
> is reclaimed from indexes."
> --
> Jim C. Nasby, Sr. Engineering Consultant [email protected]
> Pervasive Software http://pervasive.com work: 512-231-6117
> vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
>
> ---------------------------(end of broadcast)---------------------------
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> http://www.postgresql.org/docs/faq
>
--
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[email protected] | (610) 359-1001
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Index: doc/src/sgml/maintenance.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/maintenance.sgml,v
retrieving revision 1.51
diff -c -c -r1.51 maintenance.sgml
*** doc/src/sgml/maintenance.sgml 4 Nov 2005 23:14:00 -0000 1.51
--- doc/src/sgml/maintenance.sgml 7 Dec 2005 05:35:08 -0000
***************
*** 141,151 ****
command. The first form, known as <quote>lazy vacuum</quote> or
just <command>VACUUM</command>, marks expired data in tables and
indexes for future reuse; it does <emphasis>not</emphasis> attempt
! to reclaim the space used by this expired data
! immediately. Therefore, the table file is not shortened, and any
! unused space in the file is not returned to the operating
! system. This variant of <command>VACUUM</command> can be run
! concurrently with normal database operations.
</para>
<para>
--- 141,152 ----
command. The first form, known as <quote>lazy vacuum</quote> or
just <command>VACUUM</command>, marks expired data in tables and
indexes for future reuse; it does <emphasis>not</emphasis> attempt
! to reclaim the space used by this expired data unless the space is
! at the end of the table and an exclusive lock can be obtained easily
! on the table. Unused space at the start or middle of the file does
! not result in the file being shortened and space returned to the
! operating system. This variant of <command>VACUUM</command> can be
! run concurrently with normal database operations.
</para>
<para>
Attachments:
[text/plain] /bjm/diff (1.6K, 2-%2Fbjm%2Fdiff)
download | inline:
Index: doc/src/sgml/maintenance.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/maintenance.sgml,v
retrieving revision 1.51
diff -c -c -r1.51 maintenance.sgml
*** doc/src/sgml/maintenance.sgml 4 Nov 2005 23:14:00 -0000 1.51
--- doc/src/sgml/maintenance.sgml 7 Dec 2005 05:35:08 -0000
***************
*** 141,151 ****
command. The first form, known as <quote>lazy vacuum</quote> or
just <command>VACUUM</command>, marks expired data in tables and
indexes for future reuse; it does <emphasis>not</emphasis> attempt
! to reclaim the space used by this expired data
! immediately. Therefore, the table file is not shortened, and any
! unused space in the file is not returned to the operating
! system. This variant of <command>VACUUM</command> can be run
! concurrently with normal database operations.
</para>
<para>
--- 141,152 ----
command. The first form, known as <quote>lazy vacuum</quote> or
just <command>VACUUM</command>, marks expired data in tables and
indexes for future reuse; it does <emphasis>not</emphasis> attempt
! to reclaim the space used by this expired data unless the space is
! at the end of the table and an exclusive lock can be obtained easily
! on the table. Unused space at the start or middle of the file does
! not result in the file being shortened and space returned to the
! operating system. This variant of <command>VACUUM</command> can be
! run concurrently with normal database operations.
</para>
<para>
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