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Liudmila Mantrova
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DOC: review for CFS gucs added in fd195a0 commit
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‎doc/src/sgml/config.sgml

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@@ -7489,6 +7489,114 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
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</sect2>
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</sect1>
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<sect1 id="runtime-config-cfs">
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<title>Data Compression</title>
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<variablelist>
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<varlistentry id="guc-cfs-gc" xreflabel="cfs-gc">
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<term><varname>cfs_gc</varname> (<type>boolean</type>)
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<indexterm>
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<primary><varname>cfs_gc</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Enables/disables background garbage collection of compressed pages.
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Default: <literal>on</literal>
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-encryption" xreflabel="cfs-encryption">
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<term><varname>cfs_encryption</varname> (<type>boolean</type>)
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<indexterm>
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<primary><varname>cfs_encryption</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Enables/disables encryption of compressed pages.
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Default: <literal>off</literal>
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-gc-workers" xreflabel="cfs-gc-workers">
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<term><varname>cfs_gc_workers</varname> (<type>integer</type>)
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<indexterm>
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<primary><varname>cfs_gc_workers</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Number of CFS background garbage collection workers.
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Default: 1
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-level" xreflabel="cfs-level">
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<term><varname>cfs_level</varname> (<type>integer</type>)
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<indexterm>
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<primary><varname>cfs_level</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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CFS compression level: 0 &mdash; no compression, 1 &mdash; maximal speed.
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Other possible values depend on the specific compression algorithm used.
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For example, 9 for <literal>zlib</literal> or 19 for <literal>zstd</literal>.
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Default: 1
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-gc-threshold" xreflabel="cfs-gc-threshold">
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<term><varname>cfs_gc_threshold</varname> (<type>integer</type>)
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<indexterm>
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<primary><varname>cfs_gc_threshold</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Minimum percent of garbage blocks in the file required to start garbage collection.
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Default: 50%
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-gc-period" xreflabel="cfs-gc-period">
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<term><varname>cfs_gc_period</varname> (<type>integer</type>)
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<indexterm>
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<primary><varname>cfs_gc_period</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Time interval between CFS garbage collection iterations, in milliseconds.
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Default: 5 seconds
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</para>
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</listitem>
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</varlistentry>
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<varlistentry id="guc-cfs-gc-delay" xreflabel="cfs-gc-delay">
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<term><varname>cfs_gc_delay</varname> (<type>integer</type>)
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<indexterm>
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<primary><varname>cfs_gc_delay</> configuration parameter</primary>
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</indexterm>
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</term>
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<listitem>
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<para>
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Time interval for which garbage collection is paused after
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each file defragmentation, in milliseconds.
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Default: 0
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</sect1>
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<sect1 id="runtime-config-error-handling">
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<title>Error Handling</title>
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‎doc/src/sgml/func.sgml

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@@ -19641,7 +19641,151 @@ SELECT (pg_stat_file('filename')).modification;
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</para>
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</sect2>
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<sect2 id="functions-compression-control">
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<title>Compression Control Functions</title>
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<indexterm>
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<primary>cfs_start_gc</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_enable_gc</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_gc_relation</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_version</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_estimate</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_compression_ratio</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_fragmentation</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_gc_activity_processed_bytes</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_gc_activity_processed_pages</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_gc_activity_processed_files</primary>
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</indexterm>
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<indexterm>
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<primary>cfs_gc_activity_scanned_files</primary>
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</indexterm>
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<para>
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The functions shown in <xref linkend="functions-cfs-table"> provide information
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about CFS state and activity and control CFS garbage collection.
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</para>
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<table id="functions-cfs-table">
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<title>Compression Control Functions</title>
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<tgroup cols="3">
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<thead>
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<row><entry>Name</entry> <entry>Return Type</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>
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<literal><function>cfs_start_gc(n_workers integer)</function></literal>
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</entry>
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<entry><type>integer</type></entry>
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<entry>Starts garbage collection using the specified number of workers.
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You can only run this function to start the garbage collection manually
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if background garbage collection is disabled.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_enable_gc(enabled boolean)</function></literal>
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</entry>
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<entry><type>boolean</type></entry>
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<entry>Enables/disables background garbage collection. Alternatively, you can use the <xref linkend="guc-cfs-gc"> configuration variable.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_gc_relation(rel regclass)</function></literal>
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</entry>
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<entry><type>integer</type></entry>
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<entry>Performs garbage collection for a particular table. This function returns the number of processed segments.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_version()</function></literal>
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</entry>
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<entry><type>text</type></entry>
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<entry>Displays the CFS version and the specific compression algorithm used.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_estimate(rel regclass)</function></literal>
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</entry>
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<entry><type>float8</type></entry>
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<entry>Estimates the effect of table compression. Returns the average compression ratio for the first ten blocks of the relation.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_compression_ratio(rel regclass)</function></literal>
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</entry>
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<entry><type>float8</type></entry>
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<entry>Returns the actual compression ratio for all segments of the compressed relation.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_fragmentation(rel regclass)</function></literal>
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</entry>
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<entry><type>float8</type></entry>
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<entry>Returns the average fragmentation ratio of the relation files.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_gc_activity_processed_bytes()</function></literal>
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</entry>
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<entry><type>int64</type></entry>
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<entry>Returns the total size of pages processed by CFS during garbage collection.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_gc_activity_processed_pages()</function></literal>
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</entry>
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<entry><type>int64</type></entry>
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<entry>Returns the number of pages processed by CFS during garbage collection.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_gc_activity_processed_files()</function></literal>
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</entry>
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<entry><type>int64</type></entry>
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<entry>Returns the number of files compacted by CFS during garbage collection.
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</entry>
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</row>
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<row>
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<entry>
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<literal><function>cfs_gc_activity_scanned_files()</function></literal>
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</entry>
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<entry><type>int64</type></entry>
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<entry>Returns the number of files scanned by CFS during garbage collection.
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</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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</sect2>
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</sect1>
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<sect1 id="functions-trigger">

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