cde8bbc413
- more work from the SGML police - some grammar improvements: rewriting a paragraph or two, replacing contractions where (IMHO) appropriate - fix missing utility commands in lock mode docs - improve CLUSTER, REINDEX, SET SESSION AUTHORIZATION ref pages Neil Conway
298 lines
8.1 KiB
Plaintext
298 lines
8.1 KiB
Plaintext
<!--
|
|
$Header: /cvsroot/pgsql/doc/src/sgml/ref/reindex.sgml,v 1.15 2003/02/19 04:06:28 momjian Exp $
|
|
PostgreSQL documentation
|
|
-->
|
|
|
|
<refentry id="SQL-REINDEX">
|
|
<refmeta>
|
|
<refentrytitle id="SQL-REINDEX-TITLE">REINDEX</refentrytitle>
|
|
<refmiscinfo>SQL - Language Statements</refmiscinfo>
|
|
</refmeta>
|
|
<refnamediv>
|
|
<refname>
|
|
REINDEX
|
|
</refname>
|
|
<refpurpose>
|
|
rebuild corrupted indexes
|
|
</refpurpose>
|
|
</refnamediv>
|
|
<refsynopsisdiv>
|
|
<refsynopsisdivinfo>
|
|
<date>2000-03-30</date>
|
|
</refsynopsisdivinfo>
|
|
<synopsis>
|
|
REINDEX { DATABASE | TABLE | INDEX } <replaceable class="PARAMETER">name</replaceable> [ FORCE ]
|
|
</synopsis>
|
|
|
|
<refsect2 id="R2-SQL-REINDEX-1">
|
|
<refsect2info>
|
|
<date>2000-03-30</date>
|
|
</refsect2info>
|
|
<title>
|
|
Inputs
|
|
</title>
|
|
<para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>DATABASE</term>
|
|
<listitem>
|
|
<para>
|
|
Recreate all system indexes of a specified database. Indexes on
|
|
user tables are not included. This form of <command>REINDEX</> can
|
|
only be used in standalone mode (see below).
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>TABLE</term>
|
|
<listitem>
|
|
<para>
|
|
Recreate all indexes of a specified table.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>INDEX</term>
|
|
<listitem>
|
|
<para>
|
|
Recreate a specified index.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><replaceable class="PARAMETER">name</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
The name of the specific database/table/index to be reindexed.
|
|
Table and index names may be schema-qualified.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>FORCE</term>
|
|
<listitem>
|
|
<para>
|
|
Force rebuild of system indexes. Without this keyword
|
|
<command>REINDEX</> skips system indexes that are not marked invalid.
|
|
FORCE is irrelevant for <command>REINDEX INDEX</>, or when reindexing
|
|
user indexes.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
</refsect2>
|
|
|
|
<refsect2 id="R2-SQL-REINDEX-2">
|
|
<refsect2info>
|
|
<date>2000-03-30</date>
|
|
</refsect2info>
|
|
<title>
|
|
Outputs
|
|
</title>
|
|
<para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><computeroutput>
|
|
REINDEX
|
|
</computeroutput></term>
|
|
<listitem>
|
|
<para>
|
|
Message returned if the table is successfully reindexed.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
</refsect2>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1 id="R1-SQL-REINDEX-1">
|
|
<refsect1info>
|
|
<date>2000-03-30</date>
|
|
</refsect1info>
|
|
<title>
|
|
Description
|
|
</title>
|
|
<para>
|
|
<command>REINDEX</command> rebuilds an index based on the data
|
|
stored in the table, replacing the old copy of the index. There are
|
|
two main reasons to use <command>REINDEX</command>:
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>
|
|
An index has become corrupted, and no longer contains valid
|
|
data. Although in theory this should never be necessary, in
|
|
practice indexes may become corrupted due to software bugs or
|
|
hardware failures. <command>REINDEX</command> provides a
|
|
recovery method.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
The index in question contains a lot of dead index pages that
|
|
are not being reclaimed. This can occur with B+-tree indexes
|
|
under certain access patterns. <command>REINDEX</command>
|
|
provides a way to reduce the space consumption of the index by
|
|
writing a new version of the index without the dead pages. See
|
|
the <quote>Routine Reindexing</quote> section in the
|
|
&cite-admin; for more information. The rest of this section
|
|
mostly discusses how to use <command>REINDEX</command> to
|
|
recover from index corruption.
|
|
</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</para>
|
|
|
|
<para>
|
|
If you suspect corruption of an index on a user table, you can
|
|
simply rebuild that index, or all indexes on the table, using
|
|
<command>REINDEX INDEX</command> or <command>REINDEX TABLE</command>.
|
|
</para>
|
|
|
|
<note>
|
|
<para>
|
|
Another approach to dealing with a corrupted user-table index is
|
|
just to drop and recreate it. This may in fact be preferable if
|
|
you would like to maintain some semblance of normal operation on
|
|
the table meanwhile. <command>REINDEX</> acquires exclusive lock
|
|
on the table, while <command>CREATE INDEX</> only locks out writes
|
|
not reads of the table.
|
|
</para>
|
|
</note>
|
|
|
|
<para>
|
|
Things are more difficult if you need to recover from corruption of an
|
|
index on a system table. In this case it's important for the backend
|
|
doing the recovery to not have used any of the suspect indexes itself.
|
|
(Indeed, in this sort of scenario you may find that backends are
|
|
crashing immediately at start-up, due to reliance on the corrupted
|
|
indexes.) To recover safely, the postmaster must be shut down and a
|
|
stand-alone <productname>PostgreSQL</productname> backend must be
|
|
started instead, giving it
|
|
the command-line options -O and -P (these options allow system table
|
|
modifications and prevent use of system indexes, respectively). Then
|
|
issue <command>REINDEX DATABASE</>, <command>REINDEX TABLE</>,
|
|
<command>REINDEX INDEX</>, or depending on how much you want to reconstruct.
|
|
If in doubt, use <command>REINDEX DATABASE FORCE</> to force reconstruction
|
|
of all system indexes in the database. Then quit the standalone backend
|
|
and restart the postmaster.
|
|
</para>
|
|
|
|
<para>
|
|
Since this is likely the only situation when most people will ever use
|
|
a standalone backend, some usage notes might be in order:
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>
|
|
Start the backend with a command like
|
|
<screen>
|
|
<userinput>postgres -D $PGDATA -O -P my_database</userinput>
|
|
</screen>
|
|
Provide the correct path to the database area with <option>-D</>, or
|
|
make sure that the environment variable <envar>PGDATA</> is set.
|
|
Also specify the name of the particular database you want to work in.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
You can issue any SQL command, not only <command>REINDEX</>.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
Be aware that the standalone backend treats newline as the command
|
|
entry terminator; there is no intelligence about semicolons,
|
|
as there is in <application>psql</>. To continue a command
|
|
across multiple lines, you must type backslash just before each
|
|
newline except the last one.
|
|
Also, you won't have any of the conveniences of command-line editing
|
|
(no command history, for example).
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
To quit the backend, type <acronym>EOF</> (<keycombo
|
|
action="simul"><keycap>Control</><keycap>D</></>, usually).
|
|
</para>
|
|
</listitem>
|
|
|
|
</itemizedlist>
|
|
|
|
See the <xref linkend="app-postgres"> reference page for more information.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1 id="R1-SQL-REINDEX-2">
|
|
<title>
|
|
Usage
|
|
</title>
|
|
<para>
|
|
Recreate the indexes on the table <literal>mytable</literal>:
|
|
|
|
<programlisting>
|
|
REINDEX TABLE mytable;
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
Rebuild a single index:
|
|
|
|
<programlisting>
|
|
REINDEX INDEX my_index;
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
Rebuild all system indexes (this will only work in a standalone backend):
|
|
|
|
<programlisting>
|
|
REINDEX DATABASE my_database FORCE;
|
|
</programlisting>
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1 id="R1-SQL-REINDEX-3">
|
|
<title>
|
|
Compatibility
|
|
</title>
|
|
|
|
<refsect2 id="R2-SQL-REINDEX-4">
|
|
<refsect2info>
|
|
<date>2000-03-30</date>
|
|
</refsect2info>
|
|
<title>
|
|
SQL92
|
|
</title>
|
|
<para>
|
|
There is no <command>REINDEX</command> in <acronym>SQL92</acronym>.
|
|
</para>
|
|
</refsect2>
|
|
</refsect1>
|
|
</refentry>
|
|
|
|
<!-- Keep this comment at the end of the file
|
|
Local variables:
|
|
mode: sgml
|
|
sgml-omittag:t
|
|
sgml-shorttag:t
|
|
sgml-minimize-attributes:nil
|
|
sgml-always-quote-attributes:t
|
|
sgml-indent-step:1
|
|
sgml-indent-data:t
|
|
sgml-parent-document:nil
|
|
sgml-default-dtd-file:"../reference.ced"
|
|
sgml-exposed-tags:nil
|
|
sgml-local-catalogs:"/usr/lib/sgml/catalog"
|
|
sgml-local-ecat-files:nil
|
|
End:
|
|
-->
|