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Major improvement in CLUSTER which preserves table characteristics using

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relfilenode.

I sent the CLUSTER patch a few days ago and I think it was missed.  I
append it again, this time including the regression test files.  For the
committer, please note that you have to cvs add the files as they don't
exist.  Maybe add to the parallel and serial schedules also, but I don't
know such stuff.

Alvaro Herrera (<alvherre[a]atentus.com>)
This commit is contained in:
Bruce Momjian
2002-08-10 20:43:46 +00:00
parent 181ca96e7a
commit 7dc40a2be0
4 changed files with 561 additions and 85 deletions
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36
doc/src/sgml/ref/cluster.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.16 2002/04/23 02:07:15 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/cluster.sgml,v 1.17 2002/08/10 20:43:46 momjian Exp $
PostgreSQL documentation
-->
@ -75,19 +75,6 @@ CLUSTER
</varlistentry>
<varlistentry>
<term><computeroutput>
ERROR: relation &lt;<replaceable class="PARAMETER">tablerelation_number</replaceable>&gt; inherits "<replaceable class="PARAMETER">table</replaceable>"
</computeroutput></term>
<listitem>
<para>
<comment>
This is not documented anywhere. It seems not to be possible to
cluster a table that is inherited.
</comment>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><computeroutput>
ERROR: Relation <replaceable class="PARAMETER">table</replaceable> does not exist!
</computeroutput></term>
<listitem>
@ -138,13 +125,6 @@ ERROR: Relation <replaceable class="PARAMETER">table</replaceable> does not exis
Notes
</title>
<para>
The table is actually copied to a temporary table in index
order, then renamed back to the original name. For this
reason, all grant permissions and other indexes are lost
when clustering is performed.
</para>
<para>
In cases where you are accessing single rows randomly
within a table, the actual order of the data in the heap
@ -194,6 +174,20 @@ SELECT <replaceable class="parameter">columnlist</replaceable> INTO TABLE <repla
fast because most of the heap data has already been
ordered, and the existing index is used.
</para>
<para>
During the cluster operation, a temporal table is created that contains
the table in the index order. Due to this, you need to have free space
on disk at least the size of the table itself, or the biggest index if
you have one that is larger than the table.
</para>
<para>
As opposed to previous releases, CLUSTER does not lose GRANT,
inheritance or foreign key information, and preserves indexes
other than the one being used for the CLUSTER.
</para>
</refsect2>
</refsect1>