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@ -1,5 +1,5 @@ |
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<!-- |
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.84 2001/09/21 20:31:43 tgl Exp $ |
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.85 2001/09/23 21:52:36 petere Exp $ |
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--> |
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<Chapter Id="runtime"> |
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@ -780,45 +780,6 @@ env PGOPTIONS='-c geqo=off' psql |
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<para> |
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<variablelist> |
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<varlistentry> |
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<term><varname>COLLECT_STARTCOLLECTOR</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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Controls whether the postmaster should start the statistics-collection |
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subprocess. This is on by default, but may be turned off if you |
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know you have no interest in collecting statistics. This option |
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can only be set at postmaster start. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>COLLECT_RESETONPMSTART</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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If on, collected statistics are zeroed out whenever the postmaster |
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is restarted. If off, statistics are accumulated across postmaster |
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restarts. The default is on. This option |
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can only be set at postmaster start. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>COLLECT_QUERYSTRING</varname> (<type>boolean</type>)</term> |
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<term><varname>COLLECT_BLOCKLEVEL</varname> (<type>boolean</type>)</term> |
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<term><varname>COLLECT_TUPLELEVEL</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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These flags determine what information backends send to the statistics |
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collector process: current queries, block-level activity statistics, |
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or tuple-level activity statistics. All default to off. Enabling |
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statistics collection costs a small amount of time per query, but |
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is invaluable for debugging and performance tuning. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>DEBUG_ASSERTIONS</varname> (<type>boolean</type>)</term> |
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<listitem> |
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@ -940,6 +901,45 @@ env PGOPTIONS='-c geqo=off' psql |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>STATS_COMMAND_STRING</varname> (<type>boolean</type>)</term> |
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<term><varname>STATS_BLOCK_LEVEL</varname> (<type>boolean</type>)</term> |
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<term><varname>STATS_ROW_LEVEL</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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These flags determine what information backends send to the statistics |
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collector process: current commands, block-level activity statistics, |
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or row-level activity statistics. All default to off. Enabling |
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statistics collection costs a small amount of time per query, but |
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is invaluable for debugging and performance tuning. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>STATS_RESET_ON_SERVER_START</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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If on, collected statistics are zeroed out whenever the server |
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is restarted. If off, statistics are accumulated across server |
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restarts. The default is on. This option |
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can only be set at server start. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>STATS_START_COLLECTOR</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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Controls whether the server should start the statistics-collection |
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subprocess. This is on by default, but may be turned off if you |
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know you have no interest in collecting statistics. This option |
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can only be set at server start. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>SYSLOG</varname> (<type>integer</type>)</term> |
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<listitem> |
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@ -1268,49 +1268,6 @@ dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir' |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>TRANSFORM_NULL_EQUALS</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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When turned on, expressions of the form |
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<literal><replaceable>expr</> = NULL</literal> (or |
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<literal>NULL = <replaceable>expr</></literal>) are treated as |
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<literal><replaceable>expr</> IS NULL</literal>, that is, they |
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return true if <replaceable>expr</> evaluates to the NULL |
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value, and false otherwise. The correct behavior of |
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<literal><replaceable>expr</> = NULL</literal> is to always |
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return NULL (unknown). Therefore this option defaults to off. |
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</para> |
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<para> |
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However, filtered forms in <productname>Microsoft |
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Access</productname> generate queries that appear to use |
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<literal><replaceable>expr</> = NULL</literal> to test for |
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NULLs, so if you use that interface to access the database you |
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might want to turn this option on. Since expressions of the |
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form <literal><replaceable>expr</> = NULL</literal> always |
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return NULL (using the correct interpretation) they are not |
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very useful and do not appear often in normal applications, so |
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this option does little harm in practice. But new users are |
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frequently confused about the semantics of expressions |
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involving NULL, so we do not turn this option on by default. |
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</para> |
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<para> |
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Note that this option only affects the literal <literal>=</> |
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operator, not other comparison operators or other expressions |
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that are computationally equivalent to some expression |
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involving the equals operator (such as <literal>IN</literal>). |
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Thus, this option is not a general fix for bad programming. |
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</para> |
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<para> |
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Refer to the <citetitle>User's Guide</citetitle> for related |
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information. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>PORT</varname> (<type>integer</type>)</term> |
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<listitem> |
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@ -1408,6 +1365,49 @@ dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir' |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>TRANSFORM_NULL_EQUALS</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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|
When turned on, expressions of the form |
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|
<literal><replaceable>expr</> = NULL</literal> (or |
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|
<literal>NULL = <replaceable>expr</></literal>) are treated as |
|
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|
<literal><replaceable>expr</> IS NULL</literal>, that is, they |
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|
return true if <replaceable>expr</> evaluates to the NULL |
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|
value, and false otherwise. The correct behavior of |
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<literal><replaceable>expr</> = NULL</literal> is to always |
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return NULL (unknown). Therefore this option defaults to off. |
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</para> |
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|
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|
<para> |
|
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|
However, filtered forms in <productname>Microsoft |
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|
Access</productname> generate queries that appear to use |
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|
|
<literal><replaceable>expr</> = NULL</literal> to test for |
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|
|
NULLs, so if you use that interface to access the database you |
|
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|
|
might want to turn this option on. Since expressions of the |
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|
|
form <literal><replaceable>expr</> = NULL</literal> always |
|
|
|
|
return NULL (using the correct interpretation) they are not |
|
|
|
|
very useful and do not appear often in normal applications, so |
|
|
|
|
this option does little harm in practice. But new users are |
|
|
|
|
frequently confused about the semantics of expressions |
|
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|
|
involving NULL, so we do not turn this option on by default. |
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|
</para> |
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<para> |
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Note that this option only affects the literal <literal>=</> |
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|
operator, not other comparison operators or other expressions |
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|
|
that are computationally equivalent to some expression |
|
|
|
|
involving the equals operator (such as <literal>IN</literal>). |
|
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|
|
Thus, this option is not a general fix for bad programming. |
|
|
|
|
</para> |
|
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|
|
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|
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|
<para> |
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|
Refer to the <citetitle>User's Guide</citetitle> for related |
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|
|
|
information. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term><varname>UNIX_SOCKET_DIRECTORY</varname> (<type>string</type>)</term> |
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<listitem> |
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