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Diffstat (limited to 'doc/src/sgml/ref/set.sgml')
| -rw-r--r-- | doc/src/sgml/ref/set.sgml | 1296 |
1 files changed, 714 insertions, 582 deletions
diff --git a/doc/src/sgml/ref/set.sgml b/doc/src/sgml/ref/set.sgml index 3328d73341e..4edea532c4a 100644 --- a/doc/src/sgml/ref/set.sgml +++ b/doc/src/sgml/ref/set.sgml @@ -12,6 +12,7 @@ SET <REFPURPOSE> Set run-time parameters for session </REFPURPOSE> + </refnamediv> <REFSYNOPSISDIV> <REFSYNOPSISDIVINFO> <DATE>1998-09-24</DATE> @@ -23,587 +24,718 @@ SET <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> { TO | = } { '<REPLACE SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL }; </SYNOPSIS> -<REFSECT2 ID="R2-SQL-SET-1"> -<REFSECT2INFO> -<DATE>1998-09-24</DATE> -</REFSECT2INFO> -<TITLE> -Inputs -</TITLE> -<PARA> - -<VARIABLELIST> -<VARLISTENTRY> -<TERM> -<REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> -</TERM> -<LISTITEM> -<para> -Settable global parameter. - -<varlistentry> -<term> -<REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE> -</term> -<listitem> -<PARA> -New value of parameter. -</variablelist> - -<para> -The possible variables and allowed values are: - -<VARIABLELIST> -<VARLISTENTRY> -<TERM> -DateStyle -</TERM> -<LISTITEM> -<PARA> - -<VARIABLELIST> -<VARLISTENTRY> -<TERM> -ISO -</TERM> -<LISTITEM> -<PARA> -use ISO 8601-style dates and times -<VARLISTENTRY> -<TERM> -SQL -</TERM> -<LISTITEM> -<PARA> -use Oracle/Ingres-style dates and times -<VARLISTENTRY> -<TERM> -Postgres -</TERM> -<LISTITEM> -<PARA> -use traditional <productname>Postgres</productname> format -<VARLISTENTRY> -<TERM> -European -</TERM> -<LISTITEM> -<PARA> -use dd/mm/yyyy for numeric date representations. -<VARLISTENTRY> -<TERM> -NonEuropean -</TERM> -<LISTITEM> -<PARA> -use mm/dd/yyyy for numeric date representations. -<VARLISTENTRY> -<TERM> -German -</TERM> -<LISTITEM> -<PARA> -use dd.mm.yyyy for numeric date representations. -<VARLISTENTRY> -<TERM> -US -</TERM> -<LISTITEM> -<PARA> -same as 'NonEuropean' -<VARLISTENTRY> -<TERM> -default -</TERM> -<LISTITEM> -<PARA> -restores the default values ('US,Postgres') -</varlistentry> -</variablelist> - -<para> - Date format initialization my be done by: -<simplelist> -<member> -Setting PGDATESTYLE environment variable. - -<member> -Running postmaster using -oe parameter to set - dates to the 'European' convention. -Note that this affects only the some combinations of date styles; for example -the ISO style is not affected by this parameter. -<member> -Changing variables in -<filename>src/backend/utils/init/globals.c</filename>. -</simplelist> - -<para> -The variables in <filename>globals.c</filename> which can be changed are: -<programlisting> -bool EuroDates = false - true -int DateStyle = USE_ISO_DATES - USE_POSTGRES_DATES - USE_ISO_DATES - USE_SQL_DATES - USE_GERMAN_DATES -</programlisting> - -</varlistentry> - -<varlistentry> -<term> -TIMEZONE -</term> -<listitem> -<para> - The possible values for timezone depends on your operating - system. For example on Linux /usr/lib/zoneinfo contains the - database of timezones. -<para> - Here are some valid values for timezone: - -<variablelist> -<varlistentry> -<term> -'PST8PDT' -</term> -<listitem> -<para> -set the timezone for California -<varlistentry> -<term> -'Portugal' -</term> -<listitem> -<para> -set time zone for Portugal. -<varlistentry> -<term> -'Europe/Rome' -</term> -<listitem> -<para> -set time zone for Italy. -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -set time zone to your local timezone -(value of the TZ environment variable). -</variablelist> - -<para> -If an invalid time zone is specified, the time zone -becomes GMT (on most systems anyway). - -<para> -A frontend which uses libpq may be initialized by setting the PGTZ -environment variable. - -<para> -The second syntax shown above, allows one to set the timezone -with a syntax similar to SQL92 <command>SET TIME ZONE</command>. -The LOCAL keyword is just an alternate form -of DEFAULT for SQL92 compatibility. - -</varlistentry> -</variablelist> - -There are also several internal or optimization - parameters which can be specified -by the <command>SET</command> command: - -<variablelist> -<varlistentry> -<term> -COST_HEAP -</term> -<listitem> -<para> -Sets the default cost of a heap scan for use by the optimizer. - -<variablelist> -<varlistentry> -<term> -<replaceable class="parameter">float4</replaceable> -</term> -<listitem> -<para> -Set the cost of a heap scan to the specified floating point value. - -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Sets the cost of a heap scan to the default value. -</variablelist> - -<para> - The frontend may be initialized by setting the PGCOSTHEAP - environment variable. - -<varlistentry> -<term> -COST_INDEX -</term> -<listitem> -<para> -Sets the default cost of an index scan for use by the optimizer. - -<variablelist> -<varlistentry> -<term> -<replaceable class="parameter">float4</replaceable> -</term> -<listitem> -<para> -Set the cost of an index scan to the specified floating point value. - -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Sets the cost of an index scan to the default value. -</variablelist> - -<para> - The frontend may be initialized by setting the PGCOSTINDEX - environment variable. - -<varlistentry> -<term> -GEQO -</term> -<listitem> -<para> -Sets the threshold for using the genetic optimizer algorithm. - -<variablelist> -<varlistentry> -<term> -On -</term> -<listitem> -<para> -enables the genetic optimizer algorithm - for statements with 8 or more tables. -<varlistentry> -<term> -On=<replaceable class="parameter">#</replaceable> -</term> -<listitem> -<para> -Takes an integer argument to enable the genetic optimizer algorithm - for statements with <replaceable class="parameter">#</replaceable> - or more tables in the query. -<varlistentry> -<term> -Off -</term> -<listitem> -<para> -disables the genetic optimizer algorithm. -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Equivalent to specifying <command>SET GEQO='on'</command> -</varlistentry> -</variablelist> - -<para> - This algorithm is on by default, which used GEQO for - statements of eight or more tables. - (See the chapter on GEQO in the Programmer's Guide -for more information). - -<para> - The frontend may be initialized by setting PGGEQO - environment variable. -</varlistentry> - -<varlistentry> -<term> -R_PLANS -</term> -<listitem> -<para> -Determines whether right-hand plan evaluation is allowed: - -<variablelist> -<varlistentry> -<term> -On -</term> -<listitem> -<para> -enables right-hand evaluation of plans. - -<varlistentry> -<term> -Off -</term> -<listitem> -<para> -disables right-hand evaluation of plans. - -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Equivalent to specifying <command>SET R_PLANS='off'</command>. -</variablelist> - -<para> - It may be useful when joining big relations with - small ones. This algorithm is off by default. - It's not used by GEQO anyway. -<para> - The frontend may be initialized by setting the PGRPLANS - environment variable. -</varlistentry> - -<varlistentry> -<term> -KSQO -</term> -<listitem> -<para> -<firstterm>Key Set Query Optimizer</firstterm> forces the query optimizer -to optimize repetative OR clauses such as generated by -<productname>MicroSoft Access</productname>: - -<variablelist> -<varlistentry> -<term> -On -</term> -<listitem> -<para> -enables this optimization. - -<varlistentry> -<term> -Off -</term> -<listitem> -<para> -disables this optimization. - -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Equivalent to specifying <command>SET KSQO='off'</command>. -</variablelist> - -<para> - It may be useful when joining big relations with - small ones. This algorithm is off by default. - It's not used by GEQO anyway. -<para> - The frontend may be initialized by setting the PGRPLANS - environment variable. - -<varlistentry> -<term> -QUERY_LIMIT -</term> -<listitem> -<para> -Sets the number of rows returned by a query. - -<variablelist> -<varlistentry> -<term> -Value -</term> -<listitem> -<para> -Maximum number of rows to return for a query. The default is to allow -an unlimited number of rows. -<varlistentry> -<term> -<replaceable class="parameter">#</replaceable> -</term> -<listitem> -<para> -Sets the maximum number of rows returned by a -query to <replaceable class="parameter">#</replaceable>. -<varlistentry> -<term> -DEFAULT -</term> -<listitem> -<para> -Sets the maximum number of rows returned by a query to be unlimited. -<para> -By default, there is no limit to the number of rows -returned by a query. -</varlistentry> - -</variablelist> - -</VARLISTENTRY> -</VARIABLELIST> -</REFSECT2> - -<REFSECT2 ID="R2-SQL-SET-2"> -<REFSECT2INFO> -<DATE>1998-09-24</DATE> -</REFSECT2INFO> -<TITLE> -Outputs -</TITLE> -<PARA> - -<VARIABLELIST> -<VARLISTENTRY> -<TERM> -<returnvalue>SET VARIABLE</returnvalue> -</TERM> -<LISTITEM> -<PARA> - Message returned if successfully. - -<VARLISTENTRY> -<TERM> -<returnvalue>WARN: Bad value for <replaceable class="parameter">variable</replaceable> (<replaceable class="parameter">value</replaceable>)</returnvalue> -</TERM> -<LISTITEM> -<PARA> - If the command fails to set variable. - -</VARIABLELIST> - -</REFSECT2> -</REFSYNOPSISDIV> - -<REFSECT1 ID="R1-SQL-SET-1"> -<REFSECT1INFO> -<DATE>1998-09-24</DATE> -</REFSECT1INFO> -<TITLE> -Description -</TITLE> -<PARA> -<command>SET</command> will modify configuration parameters for variable during + <REFSECT2 ID="R2-SQL-SET-1"> + <REFSECT2INFO> + <DATE>1998-09-24</DATE> + </REFSECT2INFO> + <TITLE> + Inputs + </TITLE> + <PARA> + + <VARIABLELIST> + <VARLISTENTRY> + <TERM> + <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> + </TERM> + <LISTITEM> + <para> + Settable global parameter. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE> + </term> + <listitem> + <PARA> + New value of parameter. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + The possible variables and allowed values are: + + <VARIABLELIST> + <VARLISTENTRY> + <TERM> + DateStyle + </TERM> + <LISTITEM> + <PARA> + + <VARIABLELIST> + <VARLISTENTRY> + <TERM> + ISO + </TERM> + <LISTITEM> + <PARA> + use ISO 8601-style dates and times + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + SQL + </TERM> + <LISTITEM> + <PARA> + use Oracle/Ingres-style dates and times + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + Postgres + </TERM> + <LISTITEM> + <PARA> + use traditional <productname>Postgres</productname> format + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + European + </TERM> + <LISTITEM> + <PARA> + use dd/mm/yyyy for numeric date representations. + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + NonEuropean + </TERM> + <LISTITEM> + <PARA> + use mm/dd/yyyy for numeric date representations. + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + German + </TERM> + <LISTITEM> + <PARA> + use dd.mm.yyyy for numeric date representations. + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + US + </TERM> + <LISTITEM> + <PARA> + same as 'NonEuropean' + </para> + </listitem> + </varlistentry> + <VARLISTENTRY> + <TERM> + default + </TERM> + <LISTITEM> + <PARA> + restores the default values ('US,Postgres') + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + Date format initialization my be done by: + <simplelist> + <member> + Setting PGDATESTYLE environment variable. + </member> + <member> + Running postmaster using -oe parameter to set + dates to the 'European' convention. + Note that this affects only the some combinations of date styles; for example + the ISO style is not affected by this parameter. + </member> + <member> + Changing variables in + <filename>src/backend/utils/init/globals.c</filename>. + </member> + </simplelist> + </para> + <para> + The variables in <filename>globals.c</filename> which can be changed are: + <programlisting> + bool EuroDates = false + true + int DateStyle = USE_ISO_DATES + USE_POSTGRES_DATES + USE_ISO_DATES + USE_SQL_DATES + USE_GERMAN_DATES + </programlisting> + </para> + <para> + <variablelist> + <varlistentry> + <term> + TIMEZONE + </term> + <listitem> + <para> + The possible values for timezone depends on your operating + system. For example on Linux /usr/lib/zoneinfo contains the + database of timezones. + </para> + <para> + Here are some valid values for timezone: + + <variablelist> + <varlistentry> + <term> + 'PST8PDT' + </term> + <listitem> + <para> + set the timezone for California + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + 'Portugal' + </term> + <listitem> + <para> + set time zone for Portugal. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + 'Europe/Rome' + </term> + <listitem> + <para> + set time zone for Italy. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + set time zone to your local timezone + (value of the TZ environment variable). + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + If an invalid time zone is specified, the time zone + becomes GMT (on most systems anyway). + </para> + <para> + A frontend which uses libpq may be initialized by setting the PGTZ + environment variable. + </para> + <para> + The second syntax shown above, allows one to set the timezone + with a syntax similar to SQL92 <command>SET TIME ZONE</command>. + The LOCAL keyword is just an alternate form + of DEFAULT for SQL92 compatibility. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + There are also several internal or optimization + parameters which can be specified + by the <command>SET</command> command: + + <variablelist> + <varlistentry> + <term> + COST_HEAP + </term> + <listitem> + <para> + Sets the default cost of a heap scan for use by the optimizer. + + <variablelist> + <varlistentry> + <term> + <replaceable class="parameter">float4</replaceable> + </term> + <listitem> + <para> + Set the cost of a heap scan to the specified floating point value. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Sets the cost of a heap scan to the default value. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + The frontend may be initialized by setting the PGCOSTHEAP + environment variable. + </para> + <variablelist> + <varlistentry> + <term> + COST_INDEX + </term> + <listitem> + <para> + Sets the default cost of an index scan for use by the optimizer. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <replaceable class="parameter">float4</replaceable> + </term> + <listitem> + <para> + Set the cost of an index scan to the specified floating point value. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Sets the cost of an index scan to the default value. + </para> + </listitem> + </varlistentry> + </variablelist> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + The frontend may be initialized by setting the PGCOSTINDEX + environment variable. + + <variablelist> + <varlistentry> + <term> + GEQO + </term> + <listitem> + <para> + Sets the threshold for using the genetic optimizer algorithm. + </para> + + <variablelist> + <varlistentry> + <term> + On + </term> + <listitem> + <para> + enables the genetic optimizer algorithm + for statements with 8 or more tables. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + On=<replaceable class="parameter">#</replaceable> + </term> + <listitem> + <para> + Takes an integer argument to enable the genetic optimizer algorithm + for statements with <replaceable class="parameter">#</replaceable> + or more tables in the query. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + Off + </term> + <listitem> + <para> + disables the genetic optimizer algorithm. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Equivalent to specifying <command>SET GEQO='on'</command> + </para> + </listitem> + </varlistentry> + </variablelist> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + This algorithm is on by default, which used GEQO for + statements of eight or more tables. + (See the chapter on GEQO in the Programmer's Guide + for more information). + </para> + <para> + The frontend may be initialized by setting PGGEQO + environment variable. + + <variablelist> + + <varlistentry> + <term> + R_PLANS + </term> + <listitem> + <para> + Determines whether right-hand plan evaluation is allowed: + </para> + + <variablelist> + <varlistentry> + <term> + On + </term> + <listitem> + <para> + enables right-hand evaluation of plans. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + Off + </term> + <listitem> + <para> + disables right-hand evaluation of plans. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Equivalent to specifying <command>SET R_PLANS='off'</command>. + </para> + </listitem> + </varlistentry> + </variablelist> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + It may be useful when joining big relations with + small ones. This algorithm is off by default. + It's not used by GEQO anyway. + </para> + <para> + The frontend may be initialized by setting the PGRPLANS + environment variable. + <variablelist> + <varlistentry> + <term> + KSQO + </term> + <listitem> + <para> + <firstterm>Key Set Query Optimizer</firstterm> forces the query optimizer + to optimize repetative OR clauses such as generated by + <productname>MicroSoft Access</productname>: + </para> + + <variablelist> + <varlistentry> + <term> + On + </term> + <listitem> + <para> + enables this optimization. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + Off + </term> + <listitem> + <para> + disables this optimization. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Equivalent to specifying <command>SET KSQO='off'</command>. + </para> + </listitem> + </varlistentry> + </variablelist> + </listitem> + </varlistentry> + </variablelist> + </para> + <para> + It may be useful when joining big relations with + small ones. This algorithm is off by default. + It's not used by GEQO anyway. + </para> + <para> + The frontend may be initialized by setting the PGRPLANS + environment variable. + <variablelist> + <varlistentry> + <term> + QUERY_LIMIT + </term> + <listitem> + <para> + Sets the number of rows returned by a query. + </para> + + <variablelist> + <varlistentry> + <term> + Value + </term> + <listitem> + <para> + Maximum number of rows to return for a query. The default is to allow + an unlimited number of rows. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <replaceable class="parameter">#</replaceable> + </term> + <listitem> + <para> + Sets the maximum number of rows returned by a + query to <replaceable class="parameter">#</replaceable>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + DEFAULT + </term> + <listitem> + <para> + Sets the maximum number of rows returned by a query to be unlimited. + </para> + </listitem> + </varlistentry> + </variablelist> + <para> + By default, there is no limit to the number of rows + returned by a query. + </para> + </listitem> + </varlistentry> + </variablelist> + </para> + </REFSECT2> + + <REFSECT2 ID="R2-SQL-SET-2"> + <REFSECT2INFO> + <DATE>1998-09-24</DATE> + </REFSECT2INFO> + <TITLE> + Outputs + </TITLE> + <PARA> + + <VARIABLELIST> + <VARLISTENTRY> + <TERM> + <returnvalue>SET VARIABLE</returnvalue> + </TERM> + <LISTITEM> + <PARA> + Message returned if successfully. + </para> + </listitem> + </varlistentry> + + <VARLISTENTRY> + <TERM> + <returnvalue>WARN: Bad value for <replaceable class="parameter">variable</replaceable> (<replaceable class="parameter">value</replaceable>)</returnvalue> + </TERM> + <LISTITEM> + <PARA> + If the command fails to set variable. + </para> + </listitem> + </varlistentry> + + </VARIABLELIST> + </para> + </REFSECT2> + </REFSYNOPSISDIV> + + <REFSECT1 ID="R1-SQL-SET-1"> + <REFSECT1INFO> + <DATE>1998-09-24</DATE> + </REFSECT1INFO> + <TITLE> + Description + </TITLE> + <PARA> + <command>SET</command> will modify configuration parameters for variable during a session. - -<para> - Current values can be obtained using <command>SHOW</command>, and values - can be restored to the defaults using <command>RESET</command>. - Parameters and values are case-insensitive. Note that the value - field is always specified as a string, so is enclosed in - single-quotes. -<para> - <command>SET TIME ZONE</command> changes the session's - default time zone offset. - A SQL-session always begins with an initial default time zone - offset. - The <command>SET TIME ZONE</command> statement is used to change the default - time zone offset for the current SQL session. - -<REFSECT2 ID="R2-SQL-SET-3"> -<REFSECT2INFO> -<DATE>1998-09-24</DATE> -</REFSECT2INFO> -<TITLE> -Notes -</TITLE> -<PARA> -The <command>SET <replaceable class="parameter">variable</replaceable></command> - statement is a <productname>Postgres</productname> language extension. - -<para> - Refer to <command>SHOW</command> and <command>RESET</command> to -display or reset the current values. - -</REFSECT2> -</REFSECT1> - -<REFSECT1 ID="R1-SQL-SET-2"> -<TITLE> -Usage -</TITLE> -<PARA> -</PARA> -<ProgramListing> ---Set the style of date to ISO: --- -SET DATESTYLE TO 'ISO'; -</programlisting> -<programlisting> ---Set GEQO to default: --- -SET GEQO = DEFAULT; -</programlisting> -<programlisting> ---Turn on right-hand evaluation of plans: --- -SET R_PLANS TO 'on'; -</programlisting> -<programlisting> ---set the timezone for Berkeley, California: -SET TIME ZONE 'PST8PDT'; - -SELECT CURRENT_TIMESTAMP AS today; - - today - ---------------------- - 1998-03-31 07:41:21-08 -</programlisting> -<programlisting> ---set the timezone for Italy: -SET TIME ZONE 'Europe/Rome'; - -SELECT CURRENT_TIMESTAMP AS today; - - today - ---------------------- - 1998-03-31 17:41:31+02 -</ProgramListing> - -</REFSECT1> - -<REFSECT1 ID="R1-SQL-SET-3"> -<TITLE> -Compatibility -</TITLE> -<PARA> -</PARA> - -<REFSECT2 ID="R2-SQL-SET-4"> -<REFSECT2INFO> -<DATE>1998-09-24</DATE> -</REFSECT2INFO> -<TITLE> -SQL92 -</TITLE> -<PARA> - There is no -<command>SET <replaceable class="parameter">variable</replaceable></command> - in <acronym>SQL92</acronym>. - - The <acronym>SQL92</acronym> syntax for <command>SET TIME ZONE</command> - is slightly different, - allowing only a single integer value for time zone specification: - -<programlisting> -SET TIME ZONE { interval_value_expression | LOCAL } -</programlisting> - + </para> + <para> + Current values can be obtained using <command>SHOW</command>, and values + can be restored to the defaults using <command>RESET</command>. + Parameters and values are case-insensitive. Note that the value + field is always specified as a string, so is enclosed in + single-quotes. + </para> + <para> + <command>SET TIME ZONE</command> changes the session's + default time zone offset. + A SQL-session always begins with an initial default time zone + offset. + The <command>SET TIME ZONE</command> statement is used to change the default + time zone offset for the current SQL session. + </para> + + <REFSECT2 ID="R2-SQL-SET-3"> + <REFSECT2INFO> + <DATE>1998-09-24</DATE> + </REFSECT2INFO> + <TITLE> + Notes + </TITLE> + <PARA> + The <command>SET <replaceable class="parameter">variable</replaceable></command> + statement is a <productname>Postgres</productname> language extension. + </para> + <para> + Refer to <command>SHOW</command> and <command>RESET</command> to + display or reset the current values. + </para> + </REFSECT2> + </REFSECT1> + + <REFSECT1 ID="R1-SQL-SET-2"> + <TITLE> + Usage + </TITLE> + <PARA> + </PARA> + <ProgramListing> + --Set the style of date to ISO: + -- + SET DATESTYLE TO 'ISO'; + </programlisting> + <programlisting> + --Set GEQO to default: + -- + SET GEQO = DEFAULT; + </programlisting> + <programlisting> + --Turn on right-hand evaluation of plans: + -- + SET R_PLANS TO 'on'; + </programlisting> + <programlisting> + --set the timezone for Berkeley, California: + SET TIME ZONE 'PST8PDT'; + + SELECT CURRENT_TIMESTAMP AS today; + + today + ---------------------- + 1998-03-31 07:41:21-08 + </programlisting> + <programlisting> + --set the timezone for Italy: + SET TIME ZONE 'Europe/Rome'; + + SELECT CURRENT_TIMESTAMP AS today; + + today + ---------------------- + 1998-03-31 17:41:31+02 + </ProgramListing> + + </REFSECT1> + + <REFSECT1 ID="R1-SQL-SET-3"> + <TITLE> + Compatibility + </TITLE> + <PARA> + </PARA> + + <REFSECT2 ID="R2-SQL-SET-4"> + <REFSECT2INFO> + <DATE>1998-09-24</DATE> + </REFSECT2INFO> + <TITLE> + SQL92 + </TITLE> + <PARA> + There is no + <command>SET <replaceable class="parameter">variable</replaceable></command> + in <acronym>SQL92</acronym>. + + The <acronym>SQL92</acronym> syntax for <command>SET TIME ZONE</command> + is slightly different, + allowing only a single integer value for time zone specification: + + <programlisting> + SET TIME ZONE { interval_value_expression | LOCAL } + </programlisting> + </para> + </refsect2> + </refsect1> </REFENTRY> |