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Commit 7d9168a

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Liudmila Mantrova
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Implemented feedback from Victor W. for AQO document
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‎doc/src/sgml/aqo.sgml

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@@ -52,12 +52,11 @@
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<filename>postgresql.conf</filename> file:
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</para>
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<programlisting>
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shared_preload_libraries = 'aqo.so'
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shared_preload_libraries = 'aqo'
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</programlisting>
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<para>
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You must preload the <filename>aqo.so</filename> library at the server startup,
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since adaptive query optimization needs to be enabled per
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database.
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You should preload the `aqo` library at the server startup, since
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adaptive query optimization needs to be enabled per database, not per connection. Otherwise, all the collected statistics will be lost when the session ends.
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</para>
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</listitem>
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<listitem>
@@ -314,39 +313,44 @@ DELETE FROM aqo_data WHERE fspace_hash = (SELECT fspace_hash FROM aqo_queries
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query planner, run:
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</para>
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<programlisting>
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UPDATE aqo_queries SET use_aqo=false, learn_aqo=false, auto_tuning=false;s
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UPDATE aqo_queries SET use_aqo=false, learn_aqo=false, auto_tuning=false;
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</programlisting>
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</sect3>
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</sect2>
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<sect2 id="aqo-reference">
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<title>Reference</title>
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<sect3 id="aqo-variables">
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<title>Configuration Variables</title>
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<para>The aqo extension provides the following configuration variables:
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</para>
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<sect4 id="aqo-mode">
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<title>aqo.mode</title>
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<para>Defines the <filename>aqo</filename> optimization modes.
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</para>
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<para><emphasis role="strong">Options:</emphasis>
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</para>
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<itemizedlist spacing="compact">
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<listitem>
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<para>
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<literal>intelligent</literal> - auto-tunes your queries based on statistics collected per query type.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>forced</literal> - optimizes all queries together, regardless of the query type.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>manual</literal> (default) - uses the default planner for all new queries, but can reuse the collected statistics for already known query types, if any.
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</para>
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</listitem>
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</itemizedlist>
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<table id="aqo-mode-options">
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<title>aqo.mode Options</title>
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<tgroup cols="2">
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<thead>
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<row><entry>Option</entry> <entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><literal>intelligent</literal></entry>
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<entry>Auto-tunes your queries based on statistics collected per query type.</entry>
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</row>
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<row>
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<entry><literal>forced</literal></entry>
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<entry>Optimizes all queries together, regardless of the query type.</entry>
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</row>
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<row>
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<entry><literal>manual</literal></entry>
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<entry><emphasis role="strong">Default.</emphasis> Uses the default planner for all new queries, but can reuse the collected statistics for already known query types, if any.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect4>
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@@ -357,54 +361,67 @@ UPDATE aqo_queries SET use_aqo=false, learn_aqo=false, auto_tuning=false;s
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<title>aqo_query_texts Table</title>
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<para>
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The <literal>aqo_query_texts</literal> table classifies all
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the query types processed by <filename>aqo</filename>. This
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table includes the following columns:
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the query types processed by <filename>aqo</filename>.
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</para>
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<itemizedlist spacing="compact">
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<listitem>
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<para>
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<literal>query_hash</literal> stores the hash value that
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uniquely identifies the query type.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>query_text</literal> provides a sample query of
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the given type.
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</para>
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</listitem>
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</itemizedlist>
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<table id="aqo-query-texts-ref">
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<title>aqo_query_texts Table</title>
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<tgroup cols="2">
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<thead>
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<row><entry>Column Name</entry> <entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><literal>query_hash</literal></entry>
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<entry>Stores the hash value that uniquely identifies the query type.</entry>
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</row>
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<row>
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<entry><literal>query_text</literal></entry>
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<entry>Provides a sample query of
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the given type.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect4>
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<sect4 id="aqo-queries-table">
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<title>aqo_queries Table</title>
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<para>
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The <literal>aqo_queries</literal> table stores optimization
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settings for different query types:
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settings for different query types.
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</para>
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<itemizedlist spacing="compact">
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<listitem>
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<para>
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<literal>query_hash</literal> stores the hash value that
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uniquely identifies the query type.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>learn_aqo</literal> enables statistics collection
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for this query type.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>use_aqo</literal> enables AQO cardinality
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<table id="aqo-queries-table-ref">
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<title>aqo_queries Table</title>
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<tgroup cols="2">
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<thead>
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<row><entry>Setting</entry><entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><literal>query_hash</literal></entry>
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<entry>Stores the hash value that uniquely identifies the query type.</entry>
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</row>
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<row>
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<entry><literal>learn_aqo</literal></entry>
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<entry>Enables statistics collection
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for this query type.</entry>
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</row>
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<row>
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<entry><literal>use_aqo</literal></entry>
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<entry>Enables <filename>aqo</filename> cardinality
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prediction for the next execution of this query type. If
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cost estimation model is incomplete, this may slow down
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query execution.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>fspace_hash</literal> is a unique identifier of
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query execution.</entry>
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</row>
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<row>
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<entry><literal>fspace_hash</literal></entry>
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<entry>Provides a unique identifier of
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the separate space in which the data for this query type
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is collected. By default, <literal>fspace_hash</literal>
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is equal to <literal>query_hash</literal>. Using this
@@ -413,21 +430,21 @@ UPDATE aqo_queries SET use_aqo=false, learn_aqo=false, auto_tuning=false;s
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amount of memory for models and even improve query
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execution performance. However, changing this setting may
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cause unexpected <filename>aqo</filename> behavior, so make sure to use it only
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if you know what you are doing.
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</para>
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</listitem>
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<listitem>
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<para>
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<literal>auto_tuning</literal> shows whether
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if you know what you are doing.</entry>
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</row>
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<row>
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<entry><literal>auto_tuning</literal></entry>
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<entry>Shows whether
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<filename>aqo</filename> tries to tune other settings for
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the given query. By default, auto-tuning in enabled in the
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intelligent mode. In other modes, new queries are not
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appended to <literal>aqo_queries</literal> automatically.
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You can change this behavior by setting the
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<literal>auto_tuning</literal> variable to TRUE.
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</para>
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</listitem>
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</itemizedlist>
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<literal>auto_tuning</literal> variable to TRUE.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect4>
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<sect4 id="aqo-data-table">
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<title>aqo_data Table</title>
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</sect4>
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</sect3>
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</sect2>
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<sect2 id="aqo-authors">
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<title>Authors</title>
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<para>
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Oleg Ivanov <email>o.ivanov@postgrespro.ru</email>,
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Postgres Professional, Moscow, Russia
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</para>
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</sect2>
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</sect1>

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