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| author | Bruce Momjian <bruce@momjian.us> | 2005-12-07 05:36:08 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2005-12-07 05:36:08 +0000 |
| commit | 5db90cc64532beb93f4d0b859562af8a5655bbdd (patch) | |
| tree | fd4f97bdc93e4b4aed2f83c972393b5f70bde591 | |
| parent | c90f02316e5980d0ec4c8eda14e8a59c4e02f747 (diff) | |
| download | postgresql-5db90cc64532beb93f4d0b859562af8a5655bbdd.tar.gz postgresql-5db90cc64532beb93f4d0b859562af8a5655bbdd.zip | |
Clarify vacuum lazy can shrink a file under certain circumstances.
| -rw-r--r-- | doc/src/sgml/maintenance.sgml | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml index 66356c0d012..532dfe0ee06 100644 --- a/doc/src/sgml/maintenance.sgml +++ b/doc/src/sgml/maintenance.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.51 2005/11/04 23:14:00 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.51.2.1 2005/12/07 05:36:08 momjian Exp $ --> <chapter id="maintenance"> @@ -141,11 +141,12 @@ $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.51 2005/11/04 23:14:00 pete 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. + 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> |