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1 | 1 | <!--
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2 | 2 | Documentation of the system catalogs, directed toward PostgreSQL developers
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3 |
| - $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.56 2002/08/30 19:23:18 tgl Exp $ |
| 3 | + $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.57 2002/09/02 05:44:43 momjian Exp $ |
4 | 4 | -->
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5 | 5 |
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6 | 6 | <chapter id="catalogs">
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161 | 161 | <entry>database users</entry>
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162 | 162 | </row>
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163 | 163 |
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| 164 | + <row> |
| 165 | + <entry>pg_settings</entry> |
| 166 | + <entry>current session run-time parameters</entry> |
| 167 | + </row> |
| 168 | + |
164 | 169 | <row>
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165 | 170 | <entry>pg_statistic</entry>
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166 | 171 | <entry>optimizer statistics</entry>
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2866 | 2871 | </sect1>
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2867 | 2872 |
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2868 | 2873 |
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| 2874 | + <sect1 id="catalog-pg-settings"> |
| 2875 | + <title>pg_settings</title> |
| 2876 | + |
| 2877 | + <para> |
| 2878 | + <structname>pg_settings</structname> virtual table allows display and update |
| 2879 | + of current session run-time parameters. There is one entry for each of the |
| 2880 | + available parameters provided by <command>SHOW ALL</command>. But it is |
| 2881 | + in a form that allows it to be joined with other relations and have a |
| 2882 | + selection criteria applied. |
| 2883 | + </para> |
| 2884 | + |
| 2885 | + <para> |
| 2886 | + An <command>UPDATE</command> performed on <structname>pg_settings</structname> |
| 2887 | + is equivalent to executing the <command>SET</command> command on that named |
| 2888 | + parameter. The change only affects the value used by the current session. If |
| 2889 | + an <command>UPDATE</command> is issued within a transaction that is later |
| 2890 | + aborted, the effects of the <command>UPDATE</command> command disappear when |
| 2891 | + the transaction is rolled back. Once the surrounding transaction is |
| 2892 | + committed, the effects will persist until the end of the session, unless |
| 2893 | + overridden by another <command>UPDATE</command> or <command>SET</command>. |
| 2894 | + </para> |
| 2895 | + |
| 2896 | + <table> |
| 2897 | + <title>pg_settings Columns</title> |
| 2898 | + |
| 2899 | + <tgroup cols=4> |
| 2900 | + <thead> |
| 2901 | + <row> |
| 2902 | + <entry>Name</entry> |
| 2903 | + <entry>Type</entry> |
| 2904 | + <entry>References</entry> |
| 2905 | + <entry>Description</entry> |
| 2906 | + </row> |
| 2907 | + </thead> |
| 2908 | + |
| 2909 | + <tbody> |
| 2910 | + <row> |
| 2911 | + <entry>name</entry> |
| 2912 | + <entry><type>text</type></entry> |
| 2913 | + <entry></entry> |
| 2914 | + <entry>The name of a current session run-time parameter</entry> |
| 2915 | + </row> |
| 2916 | + |
| 2917 | + <row> |
| 2918 | + <entry>setting</entry> |
| 2919 | + <entry><type>text</type></entry> |
| 2920 | + <entry></entry> |
| 2921 | + <entry>The value of a current session run-time parameter</entry> |
| 2922 | + </row> |
| 2923 | + </tbody> |
| 2924 | + </tgroup> |
| 2925 | + </table> |
| 2926 | + |
| 2927 | + </sect1> |
| 2928 | + |
| 2929 | + |
2869 | 2930 | <sect1 id="catalog-pg-statistic">
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2870 | 2931 | <title>pg_statistic</title>
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2871 | 2932 |
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