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Postgres FD Implementation
Commit ebfbb79f authored by Thomas G. Lockhart's avatar Thomas G. Lockhart
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Add input parameters for LOCK TABLE. Still needs explanation from Vadim. 

Fix markup.
parent 39fc8139
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doc/src/sgml/ref/lock.sgml
View file @ ebfbb79f
<REFENTRY ID="SQL-LOCK">
<REFMETA>
<REFENTRYTITLE>
<refentry id="SQL-LOCK">
<refmeta>
<refentrytitle>
LOCK
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>
LOCK
</REFNAME>
<REFPURPOSE>
</refname>
<refpurpose>
Explicit lock of a table inside a transaction
</REFPURPOSE>
</refpurpose>
</refnamediv>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-24</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
LOCK [ TABLE ] [IN [ROW|ACCESS] [SHARE|EXCLUSIVE] | [SHARE ROW EXCLUSIVE] MODE]
<REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>
</SYNOPSIS>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>1998-09-24</date>
</refsynopsisdivinfo>
<synopsis>
LOCK [ TABLE ] <replaceable class="PARAMETER">table</replaceable>
LOCK [ TABLE ] <replaceable class="PARAMETER">table</replaceable> IN [ ROW | ACCESS ] { SHARE | EXCLUSIVE } MODE
LOCK [ TABLE ] <replaceable class="PARAMETER">table</replaceable> IN SHARE ROW EXCLUSIVE MODE
</synopsis>
<REFSECT2 ID="R2-SQL-LOCK-1">
<REFSECT2INFO>
<DATE>1998-09-01</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-LOCK-1">
<refsect2info>
<date>1998-09-01</date>
</refsect2info>
<title>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
The name of an existing table to lock.
</para>
</listitem>
</varlistentry>
</VARIABLELIST>
</REFSECT2>
</title>
<para>
<variablelist>
<varlistentry>
<term>
<replaceable class="PARAMETER">table</replaceable>
</term>
<listitem>
<para>
The name of an existing table to lock.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
SHARE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
EXCLUSIVE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ROW SHARE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ROW EXCLUSIVE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<REFSECT2 ID="R2-SQL-LOCK-2">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<varlistentry>
<term>
ACCESS SHARE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ACCESS EXCLUSIVE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
SHARE ROW EXCLUSIVE MODE
</term>
<listitem>
<para>
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
<refsect2 id="R2-SQL-LOCK-2">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
Outputs
</TITLE>
<PARA>
</title>
<para>
<VARIABLELIST>
<TERM>
ERROR <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>: Table does not exist.
</TERM>
<LISTITEM>
<PARA>
Message returned if <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>
<variablelist>
<varlistentry>
<term>
ERROR <replaceable class="PARAMETER">table</replaceable>: Table does not exist.
</term>
<listitem>
<para>
Message returned if <replaceable class="PARAMETER">table</replaceable>
does not exist.
</para>
</listitem>
</varlistentry>
</VARIABLELIST>
</variablelist>
</para>
</REFSECT2>
</REFSYNOPSISDIV>
</refsect2>
</refsynopsisdiv>
<REFSECT1 ID="R1-SQL-LOCK-1">
<REFSECT1INFO>
<DATE>1998-09-24</DATE>
</REFSECT1INFO>
<TITLE>
<refsect1 id="R1-SQL-LOCK-1">
<refsect1info>
<date>1998-09-24</date>
</refsect1info>
<title>
Description
</TITLE>
<PARA>
</title>
<para>
By default, <command>LOCK</command> locks in exclusive mode a table inside
a transaction. Various options allow shared access, or row-level locking
control. The classic use for this is
......@@ -112,13 +184,13 @@
</para>
</note>
<REFSECT2 ID="R2-SQL-LOCK-3">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-LOCK-3">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
Notes
</TITLE>
</title>
<para>
<command>LOCK</command> is a <productname>Postgres</productname>
language extension.
......@@ -134,16 +206,16 @@
</para>
</note>
</para>
</REFSECT2>
</refsect2>
</refsect1>
<REFSECT1 ID="R1-SQL-LOCK-2">
<TITLE>
<refsect1 id="R1-SQL-LOCK-2">
<title>
Usage
</TITLE>
<PARA>
</PARA>
<ProgramListing>
</title>
<para>
</para>
<programlisting>
--Explicit locking to prevent deadlock:
--
BEGIN WORK;
......@@ -152,30 +224,30 @@
UPDATE films SET len = INTERVAL '100 minute'
WHERE len = INTERVAL '117 minute';
COMMIT WORK;
</ProgramListing>
</programlisting>
</REFSECT1>
</refsect1>
<REFSECT1 ID="R1-SQL-LOCK-3">
<TITLE>
<refsect1 id="R1-SQL-LOCK-3">
<title>
Compatibility
</TITLE>
</title>
<REFSECT2 ID="R2-SQL-LOCK-4">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-LOCK-4">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
SQL92
</TITLE>
<PARA>
</title>
<para>
There is no <command>LOCK TABLE</command> in <acronym>SQL92</acronym>,
which instead uses <command>SET TRANSACTION</command> to specify
concurrency level on transactions. We support that too.
</para>
</refsect2>
</refsect1>
</REFENTRY>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
......
doc/src/sgml/ref/set.sgml
View file @ ebfbb79f
<REFENTRY ID="SQL-SET">
<REFMETA>
<REFENTRYTITLE>
<refentry id="SQL-SET">
<refmeta>
<refentrytitle>
SET
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>
SET
</REFNAME>
<REFPURPOSE>
</refname>
<refpurpose>
Set run-time parameters for session
</REFPURPOSE>
</refpurpose>
</refnamediv>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-24</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
SET <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> { TO | = } { '<REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE>' | DEFAULT }
SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL };
</SYNOPSIS>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>1998-09-24</date>
</refsynopsisdivinfo>
<synopsis>
SET <replaceable class="PARAMETER">variable</replaceable> { TO | = } { '<replaceable class="PARAMETER">value</replaceable>' | DEFAULT }
SET TIME ZONE { '<replaceable class="PARAMETER">timezone</replaceable>' | LOCAL | DEFAULT };
SET TRANSACTION ISOLATION LEVEL { READ COMMITTED | SERIALIZED | DEFAULT }
</synopsis>
<REFSECT2 ID="R2-SQL-SET-1">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-SET-1">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
Inputs
</TITLE>
<PARA>
</title>
<para>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</TERM>
<LISTITEM>
<variablelist>
<varlistentry>
<term>
<replaceable class="PARAMETER">variable</replaceable>
</term>
<listitem>
<para>
Settable global parameter.
</para>
......@@ -44,146 +45,222 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
</varlistentry>
<varlistentry>
<term>
<REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE>
<replaceable class="PARAMETER">value</replaceable>
</term>
<listitem>
<PARA>
<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>
CLIENT_ENCODING | NAMES
</term>
<listitem>
<para>
Sets the multi-byte client encoding
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">value</replaceable>
</term>
<listitem>
<para>
Sets the multi-byte client encoding to
<replaceable class="parameter">value</replaceable>.
The specified encoding must be supported by the backend.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the multi-byte client encoding.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
This is only enabled if multi-byte was specified to configure.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
DateStyle
</term>
<listitem>
<para>
<variablelist>
<varlistentry>
<term>
ISO
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use ISO 8601-style dates and times
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
SQL
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use Oracle/Ingres-style dates and times
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
Postgres
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use traditional <productname>Postgres</productname> format
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
European
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use dd/mm/yyyy for numeric date representations.
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
NonEuropean
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use mm/dd/yyyy for numeric date representations.
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
German
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
use dd.mm.yyyy for numeric date representations.
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
US
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
same as 'NonEuropean'
</para>
</listitem>
</varlistentry>
<VARLISTENTRY>
<TERM>
<varlistentry>
<term>
default
</TERM>
<LISTITEM>
<PARA>
</term>
<listitem>
<para>
restores the default values ('US,Postgres')
</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:
<simplelist>
<member>
bool EuroDates = false | true
</member>
<member>
int DateStyle = USE_ISO_DATES | USE_POSTGRES_DATES | USE_SQL_DATES | USE_GERMAN_DATES
</member>
</simplelist>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
SERVER_ENCODING
</term>
<listitem>
<para>
Sets the multi-byte server encoding
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">value</replaceable>
</term>
<listitem>
<para>
Sets the multi-byte server encoding.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the multi-byte server encoding.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
This is only enabled if multi-byte was specified to configure.
</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:
<simplelist>
<member>
bool EuroDates = false | true
</member>
<member>
int DateStyle = USE_ISO_DATES | USE_POSTGRES_DATES | USE_SQL_DATES | USE_GERMAN_DATES
</member>
</simplelist>
</para>
<para>
<variablelist>
<varlistentry>
<term>
TIMEZONE
......@@ -257,8 +334,59 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
TRANSACTION ISOLATION LEVEL
</term>
<listitem>
<para>
Sets the isolation level for the current transaction.
<variablelist>
<varlistentry>
<term>
READ COMMITTED
</term>
<listitem>
<para>
The current transaction reads only
committed rows. READ COMMITTED is the default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
SERIALIZABLE
</term>
<listitem>
<para>
The current transaction will place a
lock on every row read, so later reads in that transaction
see the rows unmodified by other transactions.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the isolation level for the current transaction to
<option>READ COMMITTED</option>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
There are also several internal or optimization
parameters which can be specified
......@@ -301,295 +429,154 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
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 6 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 eleven 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.
</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.
<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 PGKSQO
environment variable.
<variablelist>
<varlistentry>
<term>
QUERY_LIMIT
COST_INDEX
</term>
<listitem>
<para>
Sets the number of rows returned by a query.
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.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the cost of an index scan to the default value.
</para>
</listitem>
</varlistentry>
</variablelist>
</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.
The frontend may be initialized by setting the PGCOSTINDEX
environment variable.
</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist>
<varlistentry>
<term>
TRANSACTION ISOLATION LEVEL
GEQO
</term>
<listitem>
<para>
Sets the isolation level for the current transaction.
Sets the threshold for using the genetic optimizer algorithm.
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">value</replaceable>
ON
</term>
<listitem>
<para>
Sets the isolation level for the current transaction to
'SERIALIZABLE' or 'READ COMMITTED'.
SERIALIZABLE means that the current transaction will place a
lock on every row read, so later reads in that transaction
see the rows unmodified by other transactions.
READ COMMITTED means that the current transaction reads only
committed rows. READ COMMITTED is the default.
enables the genetic optimizer algorithm
for statements with 6 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>
</para>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the isolation level for the current transaction to
'READ COMMITTED'.
Equivalent to specifying <command>SET GEQO='ON'</command>
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<variablelist>
<para>
This algorithm is on by default, which used GEQO for
statements of eleven 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.
</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>
</listitem>
</varlistentry>
<varlistentry>
<term>
CLIENT_ENCODING | NAMES
KSQO
</term>
<listitem>
<para>
Sets the multi-byte client encoding
<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>
<replaceable class="parameter">value</replaceable>
ON
</term>
<listitem>
<para>
Sets the multi-byte client encoding.
enables this optimization.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
OFF
</term>
<listitem>
<para>
disables this optimization.
</para>
</listitem>
</varlistentry>
</para>
<varlistentry>
<term>
......@@ -597,103 +584,113 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
</term>
<listitem>
<para>
Sets the multi-byte client encoding.
Equivalent to specifying <command>SET KSQO='OFF'</command>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
This is only enabled if multi-byte was specified to configure.
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 PGKSQO
environment variable.
</para>
</listitem>
</varlistentry>
<variablelist>
<varlistentry>
<term>
SERVER_ENCODING
QUERY_LIMIT
</term>
<listitem>
<para>
Sets the multi-byte server encoding
Sets the maximum number of rows returned by a query.
By default, there is no limit to the number of rows
returned by a query.
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">value</replaceable>
<replaceable class="parameter">#</replaceable>
</term>
<listitem>
<para>
Sets the multi-byte server encoding.
Sets the maximum number of rows returned by a
query to <replaceable class="parameter">#</replaceable>.
</para>
</listitem>
</varlistentry>
</para>
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the multi-byte server encoding.
Sets the maximum number of rows returned by a query to be unlimited.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
This is only enabled if multi-byte was specified to configure.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
</REFSECT2>
<REFSECT2 ID="R2-SQL-SET-2">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-SET-2">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
Outputs
</TITLE>
<PARA>
</title>
<para>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<variablelist>
<varlistentry>
<term>
<returnvalue>SET VARIABLE</returnvalue>
</TERM>
<LISTITEM>
<PARA>
</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.
<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 the specified variable.
</para>
</listitem>
</varlistentry>
</VARIABLELIST>
</variablelist>
</para>
</REFSECT2>
</REFSYNOPSISDIV>
</refsect2>
</refsynopsisdiv>
<REFSECT1 ID="R1-SQL-SET-1">
<REFSECT1INFO>
<DATE>1998-09-24</DATE>
</REFSECT1INFO>
<TITLE>
<refsect1 id="R1-SQL-SET-1">
<refsect1info>
<date>1998-09-24</date>
</refsect1info>
<title>
Description
</TITLE>
<PARA>
</title>
<para>
<command>SET</command> will modify configuration parameters for variable during
a session.
</para>
......@@ -707,20 +704,20 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
<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
An 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>
<refsect2 id="R2-SQL-SET-3">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
Notes
</TITLE>
<PARA>
</title>
<para>
The <command>SET <replaceable class="parameter">variable</replaceable></command>
statement is a <productname>Postgres</productname> language extension.
</para>
......@@ -728,16 +725,16 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
Refer to <command>SHOW</command> and <command>RESET</command> to
display or reset the current values.
</para>
</REFSECT2>
</REFSECT1>
</refsect2>
</refsect1>
<REFSECT1 ID="R1-SQL-SET-2">
<TITLE>
<refsect1 id="R1-SQL-SET-2">
<title>
Usage
</TITLE>
<PARA>
</PARA>
<ProgramListing>
</title>
<para>
</para>
<programlisting>
--Set the style of date to ISO:
--
SET DATESTYLE TO 'ISO';
......@@ -771,25 +768,25 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
today
----------------------
1998-03-31 17:41:31+02
</ProgramListing>
</programlisting>
</REFSECT1>
</refsect1>
<REFSECT1 ID="R1-SQL-SET-3">
<TITLE>
<refsect1 id="R1-SQL-SET-3">
<title>
Compatibility
</TITLE>
<PARA>
</PARA>
</title>
<para>
</para>
<REFSECT2 ID="R2-SQL-SET-4">
<REFSECT2INFO>
<DATE>1998-09-24</DATE>
</REFSECT2INFO>
<TITLE>
<refsect2 id="R2-SQL-SET-4">
<refsect2info>
<date>1998-09-24</date>
</refsect2info>
<title>
SQL92
</TITLE>
<PARA>
</title>
<para>
There is no
<command>SET <replaceable class="parameter">variable</replaceable></command>
in <acronym>SQL92</acronym>.
......@@ -804,7 +801,7 @@ SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL
</para>
</refsect2>
</refsect1>
</REFENTRY>
</refentry>
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Local variables:
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