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Improve wording of descriptions of SIGHUP GUC parameters, as per my 

suggestion a couple days ago.  Fix some cases in which the documentation
neglected to mention any restriction on when a parameter can be set.
Try to be consistent about calling parameters parameters; use the term
option only for command-line switches.
This commit is contained in:
Tom Lane 2006-01-23 18:16:41 +00:00
parent 80324fb1e3
commit 726b42abd0
1 changed files with 186 additions and 160 deletions
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346
doc/src/sgml/config.sgml
View File

@ -1,5 +1,5 @@
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.44 2006/01/21 19:34:42 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.45 2006/01/23 18:16:41 tgl Exp $
--> -->
<chapter Id="runtime-config"> <chapter Id="runtime-config">
<title>Server Configuration</title> <title>Server Configuration</title>
@ -93,7 +93,7 @@ env PGOPTIONS='-c geqo=off' psql
</para> </para>
<para> <para>
Furthermore, it is possible to assign a set of option settings to Furthermore, it is possible to assign a set of parameter settings to
a user or a database. Whenever a session is started, the default a user or a database. Whenever a session is started, the default
settings for the user and database involved are loaded. The settings for the user and database involved are loaded. The
commands <xref linkend="sql-alteruser" endterm="sql-alteruser-title"> commands <xref linkend="sql-alteruser" endterm="sql-alteruser-title">
@ -102,7 +102,7 @@ env PGOPTIONS='-c geqo=off' psql
settings override anything received from the settings override anything received from the
<command>postmaster</command> command-line or the configuration <command>postmaster</command> command-line or the configuration
file, and in turn are overridden by per-user settings; both are file, and in turn are overridden by per-user settings; both are
overridden by per-session options. overridden by per-session settings.
</para> </para>
<para> <para>
@ -115,8 +115,8 @@ SET ENABLE_SEQSCAN TO OFF;
If <command>SET</> is allowed, it overrides all other sources of If <command>SET</> is allowed, it overrides all other sources of
values for the parameter. Some parameters cannot be changed via values for the parameter. Some parameters cannot be changed via
<command>SET</command>: for example, if they control behavior that <command>SET</command>: for example, if they control behavior that
cannot reasonably be changed without restarting cannot be changed without restarting the entire
<productname>PostgreSQL</productname>. Also, some parameters can <productname>PostgreSQL</productname> server. Also, some parameters can
be modified via <command>SET</command> or <command>ALTER</> by superusers, be modified via <command>SET</command> or <command>ALTER</> by superusers,
but not by ordinary users. but not by ordinary users.
</para> </para>
@ -146,7 +146,7 @@ SET ENABLE_SEQSCAN TO OFF;
client authentication (their use is discussed in <xref client authentication (their use is discussed in <xref
linkend="client-authentication">). By default, all three linkend="client-authentication">). By default, all three
configuration files are stored in the database cluster's data configuration files are stored in the database cluster's data
directory. The options described in this section allow the directory. The parameters described in this section allow the
configuration files to be placed elsewhere. (Doing so can ease configuration files to be placed elsewhere. (Doing so can ease
administration. In particular it is often easier to ensure that administration. In particular it is often easier to ensure that
the configuration files are properly backed-up when they are the configuration files are properly backed-up when they are
@ -162,7 +162,7 @@ SET ENABLE_SEQSCAN TO OFF;
<listitem> <listitem>
<para> <para>
Specifies the directory to use for data storage. Specifies the directory to use for data storage.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -176,7 +176,7 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
Specifies the main server configuration file Specifies the main server configuration file
(customarily called <filename>postgresql.conf</>). (customarily called <filename>postgresql.conf</>).
This option can only be set on the postmaster command line. This parameter can only be set on the postmaster command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -190,7 +190,7 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
Specifies the configuration file for host-based authentication Specifies the configuration file for host-based authentication
(customarily called <filename>pg_hba.conf</>). (customarily called <filename>pg_hba.conf</>).
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -205,7 +205,7 @@ SET ENABLE_SEQSCAN TO OFF;
Specifies the configuration file for Specifies the configuration file for
<application>ident</> authentication <application>ident</> authentication
(customarily called <filename>pg_ident.conf</>). (customarily called <filename>pg_ident.conf</>).
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -220,15 +220,15 @@ SET ENABLE_SEQSCAN TO OFF;
Specifies the name of an additional process-id (PID) file that the Specifies the name of an additional process-id (PID) file that the
<application>postmaster</> should create for use by server <application>postmaster</> should create for use by server
administration programs. administration programs.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
</variablelist> </variablelist>
<para> <para>
In a default installation, none of the above options are set explicitly. In a default installation, none of the above parameters are set
Instead, the explicitly. Instead, the
data directory is specified by the <option>-D</option> command-line data directory is specified by the <option>-D</option> command-line
option or the <envar>PGDATA</envar> environment variable, and the option or the <envar>PGDATA</envar> environment variable, and the
configuration files are all found within the data directory. configuration files are all found within the data directory.
@ -239,7 +239,7 @@ SET ENABLE_SEQSCAN TO OFF;
data directory, the postmaster's <option>-D</option> data directory, the postmaster's <option>-D</option>
command-line option or <envar>PGDATA</envar> environment variable command-line option or <envar>PGDATA</envar> environment variable
must point to the directory containing the configuration files, must point to the directory containing the configuration files,
and the <varname>data_directory</> option must be set in and the <varname>data_directory</> parameter must be set in
<filename>postgresql.conf</filename> (or on the command line) to show <filename>postgresql.conf</filename> (or on the command line) to show
where the data directory is actually located. Notice that where the data directory is actually located. Notice that
<varname>data_directory</> overrides <option>-D</option> and <varname>data_directory</> overrides <option>-D</option> and
@ -250,17 +250,17 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
If you wish, you can specify the configuration file names and locations If you wish, you can specify the configuration file names and locations
individually using the options <varname>config_file</>, individually using the parameters <varname>config_file</>,
<varname>hba_file</> and/or <varname>ident_file</>. <varname>hba_file</> and/or <varname>ident_file</>.
<varname>config_file</> can only be specified on the <varname>config_file</> can only be specified on the
<command>postmaster</command> command line, but the others can be <command>postmaster</command> command line, but the others can be
set within the main configuration file. If all three options plus set within the main configuration file. If all three parameters plus
<varname>data_directory</> are explicitly set, then it is not necessary <varname>data_directory</> are explicitly set, then it is not necessary
to specify <option>-D</option> or <envar>PGDATA</envar>. to specify <option>-D</option> or <envar>PGDATA</envar>.
</para> </para>
<para> <para>
When setting any of these options, a relative path will be interpreted When setting any of these parameters, a relative path will be interpreted
with respect to the directory in which the <command>postmaster</command> with respect to the directory in which the <command>postmaster</command>
is started. is started.
</para> </para>
@ -386,11 +386,11 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
Sets the owning group of the Unix-domain socket. (The owning Sets the owning group of the Unix-domain socket. (The owning
user of the socket is always the user that starts the user of the socket is always the user that starts the
server.) In combination with the option server.) In combination with the parameter
<varname>unix_socket_permissions</varname> this can be used as <varname>unix_socket_permissions</varname> this can be used as
an additional access control mechanism for Unix-domain connections. an additional access control mechanism for Unix-domain connections.
By default this is the empty string, which uses the default By default this is the empty string, which selects the default
group for the current user. This option can only be set at group for the current user. This parameter can only be set at
server start. server start.
</para> </para>
</listitem> </listitem>
@ -405,7 +405,7 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
Sets the access permissions of the Unix-domain socket. Unix-domain Sets the access permissions of the Unix-domain socket. Unix-domain
sockets use the usual Unix file system permission set. sockets use the usual Unix file system permission set.
The option value is expected to be a numeric mode The parameter value is expected to be a numeric mode
specification in the form accepted by the specification in the form accepted by the
<function>chmod</function> and <function>umask</function> <function>chmod</function> and <function>umask</function>
system calls. (To use the customary octal format the number system calls. (To use the customary octal format the number
@ -428,7 +428,7 @@ SET ENABLE_SEQSCAN TO OFF;
</para> </para>
<para> <para>
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -441,10 +441,11 @@ SET ENABLE_SEQSCAN TO OFF;
<listitem> <listitem>
<para> <para>
Specifies the <productname>Bonjour</productname> broadcast Specifies the <productname>Bonjour</productname> broadcast
name. By default, the computer name is used, specified as an name. The computer name is used if this parameter is set to the
empty string ''. This option is ignored if the server was not empty string <literal>''</> (which is the default). This parameter is
compiled with <productname>Bonjour</productname> support. This ignored if the server was not compiled with
option can only be set at server start. <productname>Bonjour</productname> support.
This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -459,7 +460,7 @@ SET ENABLE_SEQSCAN TO OFF;
On systems that support the <symbol>TCP_KEEPIDLE</symbol> socket option, specifies the On systems that support the <symbol>TCP_KEEPIDLE</symbol> socket option, specifies the
number of seconds between sending keepalives on an otherwise idle number of seconds between sending keepalives on an otherwise idle
connection. A value of 0 uses the system default. If <symbol>TCP_KEEPIDLE</symbol> is connection. A value of 0 uses the system default. If <symbol>TCP_KEEPIDLE</symbol> is
not supported, this parameter must be 0. This option is ignored for not supported, this parameter must be 0. This parameter is ignored for
connections made via a Unix-domain socket. connections made via a Unix-domain socket.
</para> </para>
</listitem> </listitem>
@ -475,7 +476,7 @@ SET ENABLE_SEQSCAN TO OFF;
On systems that support the <symbol>TCP_KEEPINTVL</symbol> socket option, specifies how On systems that support the <symbol>TCP_KEEPINTVL</symbol> socket option, specifies how
long, in seconds, to wait for a response to a keepalive before long, in seconds, to wait for a response to a keepalive before
retransmitting. A value of 0 uses the system default. If <symbol>TCP_KEEPINTVL</symbol> retransmitting. A value of 0 uses the system default. If <symbol>TCP_KEEPINTVL</symbol>
is not supported, this parameter must be 0. This option is ignored is not supported, this parameter must be 0. This parameter is ignored
for connections made via a Unix-domain socket. for connections made via a Unix-domain socket.
</para> </para>
</listitem> </listitem>
@ -491,7 +492,7 @@ SET ENABLE_SEQSCAN TO OFF;
On systems that support the <symbol>TCP_KEEPCNT</symbol> socket option, specifies how On systems that support the <symbol>TCP_KEEPCNT</symbol> socket option, specifies how
many keepalives may be lost before the connection is considered dead. many keepalives may be lost before the connection is considered dead.
A value of 0 uses the system default. If <symbol>TCP_KEEPCNT</symbol> is not A value of 0 uses the system default. If <symbol>TCP_KEEPCNT</symbol> is not
supported, this parameter must be 0. This option is ignored supported, this parameter must be 0. This parameter is ignored
for connections made via a Unix-domain socket. for connections made via a Unix-domain socket.
</para> </para>
</listitem> </listitem>
@ -516,9 +517,10 @@ SET ENABLE_SEQSCAN TO OFF;
Maximum time to complete client authentication, in seconds. If a Maximum time to complete client authentication, in seconds. If a
would-be client has not completed the authentication protocol in would-be client has not completed the authentication protocol in
this much time, the server breaks the connection. This prevents this much time, the server breaks the connection. This prevents
hung clients from occupying a connection indefinitely. This hung clients from occupying a connection indefinitely.
option can only be set at server start or in the The default is 60.
<filename>postgresql.conf</filename> file. The default is 60. This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -549,7 +551,7 @@ SET ENABLE_SEQSCAN TO OFF;
linkend="sql-createuser" endterm="sql-createuser-title"> or linkend="sql-createuser" endterm="sql-createuser-title"> or
<xref linkend="sql-alteruser" endterm="sql-alteruser-title"> <xref linkend="sql-alteruser" endterm="sql-alteruser-title">
without writing either <literal>ENCRYPTED</> or without writing either <literal>ENCRYPTED</> or
<literal>UNENCRYPTED</>, this option determines whether the <literal>UNENCRYPTED</>, this parameter determines whether the
password is to be encrypted. The default is <literal>on</> password is to be encrypted. The default is <literal>on</>
(encrypt the password). (encrypt the password).
</para> </para>
@ -594,8 +596,6 @@ SET ENABLE_SEQSCAN TO OFF;
This, combined with <varname>krb_srvname</>, is used to generate This, combined with <varname>krb_srvname</>, is used to generate
the complete service principal, that is the complete service principal, that is
<varname>krb_srvname</><literal>/</><varname>krb_server_hostname</><literal>@</>REALM. <varname>krb_srvname</><literal>/</><varname>krb_server_hostname</><literal>@</>REALM.
</para>
<para>
If not set, the default is the server host name. See <xref linkend="kerberos-auth"> If not set, the default is the server host name. See <xref linkend="kerberos-auth">
for details. This parameter can only be set at server start. for details. This parameter can only be set at server start.
</para> </para>
@ -623,7 +623,9 @@ SET ENABLE_SEQSCAN TO OFF;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
This enables per-database user names. It is off by default. This parameter enables per-database user names. It is off by default.
This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
<para> <para>
@ -637,7 +639,7 @@ SET ENABLE_SEQSCAN TO OFF;
</para> </para>
<para> <para>
With this option enabled, you can still create ordinary global With this parameter enabled, you can still create ordinary global
users. Simply append <literal>@</> when specifying the user users. Simply append <literal>@</> when specifying the user
name in the client. The <literal>@</> will be stripped off name in the client. The <literal>@</> will be stripped off
before the user name is looked up by the server. before the user name is looked up by the server.
@ -680,7 +682,7 @@ SET ENABLE_SEQSCAN TO OFF;
least twice the value of <xref linkend="guc-max-connections">; least twice the value of <xref linkend="guc-max-connections">;
however, settings significantly higher than the minimum are however, settings significantly higher than the minimum are
usually needed for good performance. Values of a few thousand usually needed for good performance. Values of a few thousand
are recommended for production installations. This option can are recommended for production installations. This parameter can
only be set at server start. only be set at server start.
</para> </para>
@ -735,7 +737,7 @@ SET ENABLE_SEQSCAN TO OFF;
Setting this parameter to zero disables the prepared-transaction Setting this parameter to zero disables the prepared-transaction
feature. feature.
The default is 5. The default is 5.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
<para> <para>
@ -821,6 +823,7 @@ SET ENABLE_SEQSCAN TO OFF;
2048 KB (two megabytes), which is conservatively small and unlikely 2048 KB (two megabytes), which is conservatively small and unlikely
to risk crashes. However, it may be too small to allow execution to risk crashes. However, it may be too small to allow execution
of complex functions. of complex functions.
Only superusers can change this setting.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -870,7 +873,7 @@ SET ENABLE_SEQSCAN TO OFF;
16 * <varname>max_fsm_relations</varname>. The default is chosen 16 * <varname>max_fsm_relations</varname>. The default is chosen
by <application>initdb</> depending on the amount of available memory, by <application>initdb</> depending on the amount of available memory,
and can range from 20000 to 200000. and can range from 20000 to 200000.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -886,7 +889,7 @@ SET ENABLE_SEQSCAN TO OFF;
free space will be tracked in the shared free-space map. Roughly free space will be tracked in the shared free-space map. Roughly
seventy bytes of shared memory are consumed for each slot. seventy bytes of shared memory are consumed for each slot.
The default is 1000. The default is 1000.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -912,7 +915,7 @@ SET ENABLE_SEQSCAN TO OFF;
can really support when a large number of processes all try to open can really support when a large number of processes all try to open
that many files. If you find yourself seeing <quote>Too many open that many files. If you find yourself seeing <quote>Too many open
files</> failures, try reducing this setting. files</> failures, try reducing this setting.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -953,7 +956,7 @@ SET ENABLE_SEQSCAN TO OFF;
applicable), the library startup time is avoided when the applicable), the library startup time is avoided when the
library is first used. However, the time to start each new library is first used. However, the time to start each new
server process may increase slightly, even if that process never server process may increase slightly, even if that process never
uses the library. So this option is recommended only for uses the library. So this parameter is recommended only for
libraries that will be used in most sessions. libraries that will be used in most sessions.
</para> </para>
</listitem> </listitem>
@ -1132,8 +1135,8 @@ SET ENABLE_SEQSCAN TO OFF;
delays is 10 milliseconds; setting <varname>bgwriter_delay</> delays is 10 milliseconds; setting <varname>bgwriter_delay</>
to a value that is not a multiple of 10 may have the same to a value that is not a multiple of 10 may have the same
results as setting it to the next higher multiple of 10. results as setting it to the next higher multiple of 10.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1152,8 +1155,8 @@ SET ENABLE_SEQSCAN TO OFF;
being recycled, and writes any that are dirty. being recycled, and writes any that are dirty.
The default value is 1.0 (this is a percentage of the total number The default value is 1.0 (this is a percentage of the total number
of shared buffers). of shared buffers).
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1168,8 +1171,8 @@ SET ENABLE_SEQSCAN TO OFF;
In each round, no more than this many buffers will be written In each round, no more than this many buffers will be written
as a result of scanning soon-to-be-recycled buffers. as a result of scanning soon-to-be-recycled buffers.
The default value is 5. The default value is 5.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1190,8 +1193,8 @@ SET ENABLE_SEQSCAN TO OFF;
of shared buffers). With the default <varname>bgwriter_delay</> of shared buffers). With the default <varname>bgwriter_delay</>
setting, this will allow the entire shared buffer pool to be scanned setting, this will allow the entire shared buffer pool to be scanned
about once per minute. about once per minute.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1208,8 +1211,8 @@ SET ENABLE_SEQSCAN TO OFF;
limit is reached, the scan stops, and resumes at the next buffer limit is reached, the scan stops, and resumes at the next buffer
during the next round.) during the next round.)
The default value is 5. The default value is 5.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1252,7 +1255,7 @@ SET ENABLE_SEQSCAN TO OFF;
<term><varname>fsync</varname> (<type>boolean</type>)</term> <term><varname>fsync</varname> (<type>boolean</type>)</term>
<listitem> <listitem>
<para> <para>
If this option is on, the <productname>PostgreSQL</> server If this parameter is on, the <productname>PostgreSQL</> server
will try to make sure that updates are physically written to will try to make sure that updates are physically written to
disk, by issuing <function>fsync()</> system calls or various disk, by issuing <function>fsync()</> system calls or various
equivalent methods (see <xref linkend="guc-wal-sync-method">). equivalent methods (see <xref linkend="guc-wal-sync-method">).
@ -1290,9 +1293,9 @@ SET ENABLE_SEQSCAN TO OFF;
</para> </para>
<para> <para>
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. If you turn file or on the server command line.
this option off, also consider turning off If you turn this parameter off, also consider turning off
<xref linkend="guc-full-page-writes">. <xref linkend="guc-full-page-writes">.
</para> </para>
</listitem> </listitem>
@ -1339,9 +1342,10 @@ SET ENABLE_SEQSCAN TO OFF;
</itemizedlist> </itemizedlist>
<para> <para>
Not all of these choices are available on all platforms. Not all of these choices are available on all platforms.
The default is the first method in the above list that is supported. The default is the first method in the above list that is supported
This option can only be set at server start or in the by the platform.
<filename>postgresql.conf</filename> file. This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1353,7 +1357,7 @@ SET ENABLE_SEQSCAN TO OFF;
<term><varname>full_page_writes</varname> (<type>boolean</type>)</term> <term><varname>full_page_writes</varname> (<type>boolean</type>)</term>
<listitem> <listitem>
<para> <para>
When this option is on, the <productname>PostgreSQL</> server When this parameter is on, the <productname>PostgreSQL</> server
writes the entire content of each disk page to WAL during the writes the entire content of each disk page to WAL during the
first modification of that page after a checkpoint. first modification of that page after a checkpoint.
This is needed because This is needed because
@ -1371,25 +1375,25 @@ SET ENABLE_SEQSCAN TO OFF;
</para> </para>
<para> <para>
Turning this option off speeds normal operation, but Turning this parameter off speeds normal operation, but
might lead to a corrupt database after an operating system crash might lead to a corrupt database after an operating system crash
or power failure. The risks are similar to turning off or power failure. The risks are similar to turning off
<varname>fsync</>, though smaller. It may be safe to turn off <varname>fsync</>, though smaller. It may be safe to turn off
this option if you have hardware (such as a battery-backed disk this parameter if you have hardware (such as a battery-backed disk
controller) or filesystem software (e.g., Reiser4) that reduces controller) or filesystem software (e.g., Reiser4) that reduces
the risk of partial page writes to an acceptably low level. the risk of partial page writes to an acceptably low level.
</para> </para>
<para> <para>
Turning off this option does not affect use of Turning off this parameter does not affect use of
WAL archiving for point-in-time recovery (PITR) WAL archiving for point-in-time recovery (PITR)
(see <xref linkend="backup-online">). (see <xref linkend="backup-online">).
</para> </para>
<para> <para>
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. The default is file or on the server command line.
<literal>on</>. The default is <literal>on</>.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1405,7 +1409,7 @@ SET ENABLE_SEQSCAN TO OFF;
The default is 8. The setting need only be large enough to hold The default is 8. The setting need only be large enough to hold
the amount of WAL data generated by one typical transaction, since the amount of WAL data generated by one typical transaction, since
the data is written out to disk at every transaction commit. the data is written out to disk at every transaction commit.
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
<para> <para>
@ -1471,8 +1475,9 @@ SET ENABLE_SEQSCAN TO OFF;
<para> <para>
Maximum distance between automatic WAL checkpoints, in log Maximum distance between automatic WAL checkpoints, in log
file segments (each segment is normally 16 megabytes). The file segments (each segment is normally 16 megabytes). The
default is three. This option can only be set at server start default is three.
or in the <filename>postgresql.conf</filename> file. This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1485,9 +1490,9 @@ SET ENABLE_SEQSCAN TO OFF;
<listitem> <listitem>
<para> <para>
Maximum time between automatic WAL checkpoints, in Maximum time between automatic WAL checkpoints, in
seconds. The default is 300 seconds. This option can only be seconds. The default is 300 seconds.
set at server start or in the <filename>postgresql.conf</> This parameter can only be set in the <filename>postgresql.conf</>
file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1504,6 +1509,8 @@ SET ENABLE_SEQSCAN TO OFF;
than this many seconds (which suggests that than this many seconds (which suggests that
<varname>checkpoint_segments</> ought to be raised). The default is <varname>checkpoint_segments</> ought to be raised). The default is
30 seconds. Zero disables the warning. 30 seconds. Zero disables the warning.
This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -1528,9 +1535,9 @@ SET ENABLE_SEQSCAN TO OFF;
<literal>%f</> is replaced by the file name only. Use <literal>%f</> is replaced by the file name only. Use
<literal>%%</> to embed an actual <literal>%</> character in the <literal>%%</> to embed an actual <literal>%</> character in the
command. For more information see <xref command. For more information see <xref
linkend="backup-archiving-wal">. This option can only be set at linkend="backup-archiving-wal">.
server start or in the <filename>postgresql.conf</filename> This parameter can only be set in the <filename>postgresql.conf</>
file. file or on the server command line.
</para> </para>
<para> <para>
It is important for the command to return a zero exit status if It is important for the command to return a zero exit status if
@ -2096,11 +2103,11 @@ SELECT * FROM parent WHERE key = 2400;
<systemitem>stderr</systemitem> and <systemitem>stderr</systemitem> and
<systemitem>syslog</systemitem>. On Windows, <systemitem>syslog</systemitem>. On Windows,
<systemitem>eventlog</systemitem> is also supported. Set this <systemitem>eventlog</systemitem> is also supported. Set this
option to a list of desired log destinations separated by parameter to a list of desired log destinations separated by
commas. The default is to log to <systemitem>stderr</systemitem> commas. The default is to log to <systemitem>stderr</systemitem>
only. only.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2112,14 +2119,14 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
This option allows messages sent to <application>stderr</> to be This parameter allows messages sent to <application>stderr</> to be
captured and redirected into log files. captured and redirected into log files.
This option, in combination with logging to <application>stderr</>, This method, in combination with logging to <application>stderr</>,
is often more useful than is often more useful than
logging to <application>syslog</>, since some types of messages logging to <application>syslog</>, since some types of messages
may not appear in <application>syslog</> output (a common example may not appear in <application>syslog</> output (a common example
is dynamic-linker failure messages). is dynamic-linker failure messages).
This option can only be set at server start. This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2131,12 +2138,12 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When <varname>redirect_stderr</> is enabled, this option When <varname>redirect_stderr</> is enabled, this parameter
determines the directory in which log files will be created. determines the directory in which log files will be created.
It may be specified as an absolute path, or relative to the It may be specified as an absolute path, or relative to the
cluster data directory. cluster data directory.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2148,7 +2155,7 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When <varname>redirect_stderr</varname> is enabled, this option When <varname>redirect_stderr</varname> is enabled, this parameter
sets the file names of the created log files. The value sets the file names of the created log files. The value
is treated as a <systemitem>strftime</systemitem> pattern, is treated as a <systemitem>strftime</systemitem> pattern,
so <literal>%</literal>-escapes so <literal>%</literal>-escapes
@ -2159,8 +2166,8 @@ SELECT * FROM parent WHERE key = 2400;
if <varname>log_filename</varname> were <literal>server_log</literal>, then the if <varname>log_filename</varname> were <literal>server_log</literal>, then the
chosen file name would be <literal>server_log.1093827753</literal> chosen file name would be <literal>server_log.1093827753</literal>
for a log starting at Sun Aug 29 19:02:33 2004 MST. for a log starting at Sun Aug 29 19:02:33 2004 MST.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2172,13 +2179,13 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When <varname>redirect_stderr</varname> is enabled, this option When <varname>redirect_stderr</varname> is enabled, this parameter
determines the maximum lifetime of an individual log file. determines the maximum lifetime of an individual log file.
After this many minutes have elapsed, a new log file will After this many minutes have elapsed, a new log file will
be created. Set to zero to disable time-based creation of be created. Set to zero to disable time-based creation of
new log files. new log files.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2190,13 +2197,13 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When <varname>redirect_stderr</varname> is enabled, this option When <varname>redirect_stderr</varname> is enabled, this parameter
determines the maximum size of an individual log file. determines the maximum size of an individual log file.
After this many kilobytes have been emitted into a log file, After this many kilobytes have been emitted into a log file,
a new log file will be created. Set to zero to disable size-based a new log file will be created. Set to zero to disable size-based
creation of new log files. creation of new log files.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2208,18 +2215,18 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When <varname>redirect_stderr</varname> is enabled, this option will cause When <varname>redirect_stderr</varname> is enabled, this parameter will cause
<productname>PostgreSQL</productname> to truncate (overwrite), <productname>PostgreSQL</productname> to truncate (overwrite),
rather than append to, any existing log file of the same name. rather than append to, any existing log file of the same name.
However, truncation will occur only when a new file is being opened However, truncation will occur only when a new file is being opened
due to time-based rotation, not during server startup or size-based due to time-based rotation, not during server startup or size-based
rotation. When off, pre-existing files will be appended to in rotation. When off, pre-existing files will be appended to in
all cases. For example, using this option in combination with all cases. For example, using this setting in combination with
a <varname>log_filename</varname> like <literal>postgresql-%H.log</literal> a <varname>log_filename</varname> like <literal>postgresql-%H.log</literal>
would result in generating twenty-four hourly log files and then would result in generating twenty-four hourly log files and then
cyclically overwriting them. cyclically overwriting them.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
<para> <para>
Example: To keep 7 days of logs, one log file per day named Example: To keep 7 days of logs, one log file per day named
@ -2250,7 +2257,7 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When logging to <application>syslog</> is enabled, this option When logging to <application>syslog</> is enabled, this parameter
determines the <application>syslog</application> determines the <application>syslog</application>
<quote>facility</quote> to be used. You may choose <quote>facility</quote> to be used. You may choose
from <literal>LOCAL0</>, <literal>LOCAL1</>, from <literal>LOCAL0</>, <literal>LOCAL1</>,
@ -2259,8 +2266,8 @@ SELECT * FROM parent WHERE key = 2400;
the default is <literal>LOCAL0</>. See also the the default is <literal>LOCAL0</>. See also the
documentation of your system's documentation of your system's
<application>syslog</application> daemon. <application>syslog</application> daemon.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2272,13 +2279,13 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
When logging to <application>syslog</> is enabled, this option When logging to <application>syslog</> is enabled, this parameter
determines the program name used to identify determines the program name used to identify
<productname>PostgreSQL</productname> messages in <productname>PostgreSQL</productname> messages in
<application>syslog</application> logs. The default is <application>syslog</application> logs. The default is
<literal>postgres</literal>. <literal>postgres</literal>.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2369,7 +2376,7 @@ SELECT * FROM parent WHERE key = 2400;
<literal>FATAL</literal>, and <literal>PANIC</literal>. For <literal>FATAL</literal>, and <literal>PANIC</literal>. For
example, if you set this to <literal>ERROR</literal> then all example, if you set this to <literal>ERROR</literal> then all
SQL statements causing errors, fatal errors, or panics will be SQL statements causing errors, fatal errors, or panics will be
logged. Enabling this option can be helpful in tracking down logged. Enabling this parameter can be helpful in tracking down
the source of any errors that appear in the server log. the source of any errors that appear in the server log.
Only superusers can change this setting. Only superusers can change this setting.
</para> </para>
@ -2389,7 +2396,7 @@ SELECT * FROM parent WHERE key = 2400;
and their durations. Minus-one (the default) disables the and their durations. Minus-one (the default) disables the
feature. For example, if you set it to <literal>250</literal> feature. For example, if you set it to <literal>250</literal>
then all SQL statements that run 250ms or longer will be then all SQL statements that run 250ms or longer will be
logged. Enabling this option can be useful in tracking down logged. Enabling this parameter can be useful in tracking down
unoptimized queries in your applications. This setting is unoptimized queries in your applications. This setting is
independent of <varname>log_statement</varname> and independent of <varname>log_statement</varname> and
<varname>log_duration</varname>. Only superusers can change <varname>log_duration</varname>. Only superusers can change
@ -2405,14 +2412,15 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
Runs the server silently. If this option is set, the server Runs the server silently. If this parameter is set, the server
will automatically run in background and any controlling will automatically run in background and any controlling
terminals are disassociated. terminals are disassociated.
The server's standard output and standard error are redirected The server's standard output and standard error are redirected
to <literal>/dev/null</>, so any messages sent to them will be lost. to <literal>/dev/null</>, so any messages sent to them will be lost.
Unless <application>syslog</> logging is selected or Unless <application>syslog</> logging is selected or
<varname>redirect_stderr</> is enabled, using this option <varname>redirect_stderr</> is enabled, using this parameter
is discouraged because it makes it impossible to see error messages. is discouraged because it makes it impossible to see error messages.
This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2527,7 +2535,7 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
These options enable various debugging output to be emitted. These parameters enable various debugging output to be emitted.
For each executed query, they print For each executed query, they print
the resulting parse tree, the query rewriter output, or the the resulting parse tree, the query rewriter output, or the
execution plan. <varname>debug_pretty_print</varname> indents execution plan. <varname>debug_pretty_print</varname> indents
@ -2536,7 +2544,7 @@ SELECT * FROM parent WHERE key = 2400;
<varname>log_min_messages</varname> must be <varname>log_min_messages</varname> must be
<literal>DEBUG1</literal> or lower to actually send this output <literal>DEBUG1</literal> or lower to actually send this output
to the client or the server log, respectively. to the client or the server log, respectively.
These options are off by default. These parameters are off by default.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2553,8 +2561,9 @@ SELECT * FROM parent WHERE key = 2400;
useful. Some client programs, like <application>psql</>, attempt useful. Some client programs, like <application>psql</>, attempt
to connect twice while determining if a password is required, so to connect twice while determining if a password is required, so
duplicate <quote>connection received</> messages do not duplicate <quote>connection received</> messages do not
necessarily indicate a problem. This option can only be set at necessarily indicate a problem.
server start or in the <filename>postgresql.conf</> configuration file. This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2569,8 +2578,9 @@ SELECT * FROM parent WHERE key = 2400;
This outputs a line in the server log similar to This outputs a line in the server log similar to
<varname>log_connections</varname> but at session termination, <varname>log_connections</varname> but at session termination,
and includes the duration of the session. This is off by and includes the duration of the session. This is off by
default. This option can only be set at server start or in the default.
<filename>postgresql.conf</filename> configuration file. This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2611,8 +2621,8 @@ SELECT * FROM parent WHERE key = 2400;
produces its own produces its own
time stamp and process ID information, so you probably do not want to time stamp and process ID information, so you probably do not want to
use those escapes if you are using <application>syslog</>. use those escapes if you are using <application>syslog</>.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
<informaltable> <informaltable>
<tgroup cols="3"> <tgroup cols="3">
@ -2758,11 +2768,11 @@ SELECT * FROM parent WHERE key = 2400;
<listitem> <listitem>
<para> <para>
By default, connection log messages only show the IP address of the By default, connection log messages only show the IP address of the
connecting host. Turning on this option causes logging of the connecting host. Turning on this parameter causes logging of the
host name as well. Note that depending on your host name resolution host name as well. Note that depending on your host name resolution
setup this might impose a non-negligible performance penalty. This setup this might impose a non-negligible performance penalty.
option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2813,6 +2823,15 @@ SELECT * FROM parent WHERE key = 2400;
</sect2> </sect2>
<sect2 id="runtime-config-statistics-collector"> <sect2 id="runtime-config-statistics-collector">
<title>Query and Index Statistics Collector</title> <title>Query and Index Statistics Collector</title>
<para>
These parameters control a server-wide statistics collection feature.
When statistics collection is enabled, the data that is produced can be
accessed via the <structname>pg_stat</structname> and
<structname>pg_statio</structname> family of system views.
Refer to <xref linkend="monitoring"> for more information.
</para>
<variablelist> <variablelist>
<varlistentry id="guc-stats-start-collector" xreflabel="stats_start_collector"> <varlistentry id="guc-stats-start-collector" xreflabel="stats_start_collector">
@ -2826,7 +2845,7 @@ SELECT * FROM parent WHERE key = 2400;
statistics-collection subprocess. This is on by default, but statistics-collection subprocess. This is on by default, but
may be turned off if you know you have no interest in may be turned off if you know you have no interest in
collecting statistics or running autovacuum. collecting statistics or running autovacuum.
This option can only be set at server start, because the collection This parameter can only be set at server start, because the collection
subprocess cannot be started or stopped on-the-fly. (However, the subprocess cannot be started or stopped on-the-fly. (However, the
extent to which statistics are actually gathered can be changed while extent to which statistics are actually gathered can be changed while
the server is running, so long as the subprocess exists.) the server is running, so long as the subprocess exists.)
@ -2843,13 +2862,12 @@ SELECT * FROM parent WHERE key = 2400;
<para> <para>
Enables the collection of statistics on the currently Enables the collection of statistics on the currently
executing command of each session, along with the time at executing command of each session, along with the time at
which that command began execution. This option is off by which that command began execution. This parameter is off by
default. Note that even when enabled, this information is not default. Note that even when enabled, this information is not
visible to all users, only to superusers and the user owning visible to all users, only to superusers and the user owning
the session being reported on; so it should not represent a the session being reported on; so it should not represent a
security risk. This data can be accessed via the security risk.
<structname>pg_stat_activity</structname> system view; refer Only superusers can change this setting.
to <xref linkend="monitoring"> for more information.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2862,11 +2880,8 @@ SELECT * FROM parent WHERE key = 2400;
<listitem> <listitem>
<para> <para>
Enables the collection of block-level statistics on database Enables the collection of block-level statistics on database
activity. This option is disabled by default. If this option activity. This parameter is off by default.
is enabled, the data that is produced can be accessed via the Only superusers can change this setting.
<structname>pg_stat</structname> and
<structname>pg_statio</structname> family of system views;
refer to <xref linkend="monitoring"> for more information.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2879,11 +2894,8 @@ SELECT * FROM parent WHERE key = 2400;
<listitem> <listitem>
<para> <para>
Enables the collection of row-level statistics on database Enables the collection of row-level statistics on database
activity. This option is disabled by default. If this option activity. This parameter is off by default.
is enabled, the data that is produced can be accessed via the Only superusers can change this setting.
<structname>pg_stat</structname> and
<structname>pg_statio</structname> family of system views;
refer to <xref linkend="monitoring"> for more information.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2897,7 +2909,7 @@ SELECT * FROM parent WHERE key = 2400;
<para> <para>
If on, collected statistics are zeroed out whenever the server If on, collected statistics are zeroed out whenever the server
is restarted. If off, statistics are accumulated across server is restarted. If off, statistics are accumulated across server
restarts. The default is <literal>off</>. This option can only restarts. The default is <literal>off</>. This parameter can only
be set at server start. be set at server start.
</para> </para>
</listitem> </listitem>
@ -2917,7 +2929,7 @@ SELECT * FROM parent WHERE key = 2400;
<para> <para>
These settings control the behavior of the <firstterm>autovacuum</> These settings control the behavior of the <firstterm>autovacuum</>
feature. Please refer to <xref linkend="autovacuum"> for feature. Refer to <xref linkend="autovacuum"> for
more information. more information.
</para> </para>
@ -2934,8 +2946,8 @@ SELECT * FROM parent WHERE key = 2400;
autovacuum daemon. This is off by default. autovacuum daemon. This is off by default.
<varname>stats_start_collector</> and <varname>stats_row_level</> <varname>stats_start_collector</> and <varname>stats_row_level</>
must also be turned on for autovacuum to work. must also be turned on for autovacuum to work.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2952,8 +2964,8 @@ SELECT * FROM parent WHERE key = 2400;
and issues <command>VACUUM</> and <command>ANALYZE</> commands and issues <command>VACUUM</> and <command>ANALYZE</> commands
as needed for tables in that database. The delay is measured as needed for tables in that database. The delay is measured
in seconds, and the default is 60. in seconds, and the default is 60.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -2968,8 +2980,8 @@ SELECT * FROM parent WHERE key = 2400;
Specifies the minimum number of updated or deleted tuples needed Specifies the minimum number of updated or deleted tuples needed
to trigger a <command>VACUUM</> in any one table. to trigger a <command>VACUUM</> in any one table.
The default is 1000. The default is 1000.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -2986,8 +2998,8 @@ SELECT * FROM parent WHERE key = 2400;
Specifies the minimum number of inserted, updated or deleted tuples Specifies the minimum number of inserted, updated or deleted tuples
needed to trigger an <command>ANALYZE</> in any one table. needed to trigger an <command>ANALYZE</> in any one table.
The default is 500. The default is 500.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -3005,8 +3017,8 @@ SELECT * FROM parent WHERE key = 2400;
<varname>autovacuum_vacuum_threshold</varname> <varname>autovacuum_vacuum_threshold</varname>
when deciding whether to trigger a <command>VACUUM</>. when deciding whether to trigger a <command>VACUUM</>.
The default is 0.4. The default is 0.4.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -3024,8 +3036,8 @@ SELECT * FROM parent WHERE key = 2400;
<varname>autovacuum_analyze_threshold</varname> <varname>autovacuum_analyze_threshold</varname>
when deciding whether to trigger an <command>ANALYZE</>. when deciding whether to trigger an <command>ANALYZE</>.
The default is 0.2. The default is 0.2.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> file. file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -3043,6 +3055,8 @@ SELECT * FROM parent WHERE key = 2400;
<command>VACUUM</> operations. If -1 is specified (which is the <command>VACUUM</> operations. If -1 is specified (which is the
default), the regular default), the regular
<xref linkend="guc-vacuum-cost-delay"> value will be used. <xref linkend="guc-vacuum-cost-delay"> value will be used.
This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -3060,6 +3074,8 @@ SELECT * FROM parent WHERE key = 2400;
<command>VACUUM</> operations. If -1 is specified (which is the <command>VACUUM</> operations. If -1 is specified (which is the
default), the regular default), the regular
<xref linkend="guc-vacuum-cost-limit"> value will be used. <xref linkend="guc-vacuum-cost-limit"> value will be used.
This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
This setting can be overridden for individual tables by entries in This setting can be overridden for individual tables by entries in
<structname>pg_autovacuum</>. <structname>pg_autovacuum</>.
</para> </para>
@ -3384,6 +3400,11 @@ SELECT * FROM parent WHERE key = 2400;
desired language exist. In that case you will continue to see desired language exist. In that case you will continue to see
the English messages. the English messages.
</para> </para>
<para>
Only superusers can change this setting, because it affects the
messages sent to the postmaster log as well as to the client.
</para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -3577,7 +3598,7 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
The default, 64, has historically The default, 64, has historically
proven sufficient, but you might need to raise this value if you proven sufficient, but you might need to raise this value if you
have clients that touch many different tables in a single have clients that touch many different tables in a single
transaction. This option can only be set at server start. transaction. This parameter can only be set at server start.
</para> </para>
<para> <para>
@ -3768,7 +3789,7 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
return true if <replaceable>expr</> evaluates to the null value, return true if <replaceable>expr</> evaluates to the null value,
and false otherwise. The correct SQL-spec-compliant behavior of and false otherwise. The correct SQL-spec-compliant behavior of
<literal><replaceable>expr</> = NULL</literal> is to always <literal><replaceable>expr</> = NULL</literal> is to always
return null (unknown). Therefore this option defaults to return null (unknown). Therefore this parameter defaults to
<literal>off</>. <literal>off</>.
</para> </para>
@ -3984,7 +4005,7 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
<title>Customized Options</title> <title>Customized Options</title>
<para> <para>
This feature was designed to allow options not normally known to This feature was designed to allow parameters not normally known to
<productname>PostgreSQL</productname> to be added by add-on modules <productname>PostgreSQL</productname> to be added by add-on modules
(such as procedural languages). This allows add-on modules to be (such as procedural languages). This allows add-on modules to be
configured in the standard ways. configured in the standard ways.
@ -4006,8 +4027,8 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
add-on module. Such variables must have names consisting of a class add-on module. Such variables must have names consisting of a class
name, a dot, and a variable name. <varname>custom_variable_classes</> name, a dot, and a variable name. <varname>custom_variable_classes</>
specifies all the class names in use in a particular installation. specifies all the class names in use in a particular installation.
This option can only be set at server start or in the This parameter can only be set in the <filename>postgresql.conf</>
<filename>postgresql.conf</filename> configuration file. file or on the server command line.
</para> </para>
</listitem> </listitem>
@ -4046,13 +4067,13 @@ plruby.use_strict = true # generates error: unknown class name
<title>Developer Options</title> <title>Developer Options</title>
<para> <para>
The following options are intended for work on the The following parameters are intended for work on the
<productname>PostgreSQL</productname> source, and in some cases <productname>PostgreSQL</productname> source, and in some cases
to assist with recovery of severely damaged databases. There to assist with recovery of severely damaged databases. There
should be no reason to use them in a production database setup. should be no reason to use them in a production database setup.
As such, they have been excluded from the sample As such, they have been excluded from the sample
<filename>postgresql.conf</> file. Note that many of these <filename>postgresql.conf</> file. Note that many of these
options require special source compilation flags to work at all. parameters require special source compilation flags to work at all.
</para> </para>
<variablelist> <variablelist>
@ -4063,8 +4084,9 @@ plruby.use_strict = true # generates error: unknown class name
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
Allows the modification of the structure of system tables. Allows modification of the structure of system tables.
This is used by <command>initdb</command>. This is used by <command>initdb</command>.
This parameter can only be set at server start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -4079,7 +4101,7 @@ plruby.use_strict = true # generates error: unknown class name
Turns on various assertion checks. This is a debugging aid. If Turns on various assertion checks. This is a debugging aid. If
you are experiencing strange problems or crashes you might want you are experiencing strange problems or crashes you might want
to turn this on, as it might expose programming mistakes. To use to turn this on, as it might expose programming mistakes. To use
this option, the macro <symbol>USE_ASSERT_CHECKING</symbol> this parameter, the macro <symbol>USE_ASSERT_CHECKING</symbol>
must be defined when <productname>PostgreSQL</productname> is must be defined when <productname>PostgreSQL</productname> is
built (accomplished by the <command>configure</command> option built (accomplished by the <command>configure</command> option
<option>--enable-cassert</option>). Note that <option>--enable-cassert</option>). Note that
@ -4100,6 +4122,7 @@ plruby.use_strict = true # generates error: unknown class name
Ignore system indexes when reading system tables (but still Ignore system indexes when reading system tables (but still
update the indexes when modifying the tables). This is useful update the indexes when modifying the tables). This is useful
when recovering from damaged system indexes. when recovering from damaged system indexes.
This parameter cannot be changed after session start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -4115,6 +4138,7 @@ plruby.use_strict = true # generates error: unknown class name
server process is started, after it conducts the server process is started, after it conducts the
authentication procedure. This is intended to give an authentication procedure. This is intended to give an
opportunity to attach to the server process with a debugger. opportunity to attach to the server process with a debugger.
This parameter cannot be changed after session start.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -4131,6 +4155,8 @@ plruby.use_strict = true # generates error: unknown class name
authentication procedure. This is intended to give an authentication procedure. This is intended to give an
opportunity to attach to the server process with a debugger to opportunity to attach to the server process with a debugger to
trace down misbehavior in authentication. trace down misbehavior in authentication.
This parameter can only be set in the <filename>postgresql.conf</>
file or on the server command line.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -4160,7 +4186,7 @@ plruby.use_strict = true # generates error: unknown class name
<listitem> <listitem>
<para> <para>
If on, emit information about resource usage during sort operations. If on, emit information about resource usage during sort operations.
This option is only available if the <symbol>TRACE_SORT</symbol> macro This parameter is only available if the <symbol>TRACE_SORT</symbol> macro
was defined when <productname>PostgreSQL</productname> was compiled. was defined when <productname>PostgreSQL</productname> was compiled.
(However, <symbol>TRACE_SORT</symbol> is currently defined by default.) (However, <symbol>TRACE_SORT</symbol> is currently defined by default.)
</para> </para>
@ -4189,7 +4215,7 @@ plruby.use_strict = true # generates error: unknown class name
</indexterm> </indexterm>
<listitem> <listitem>
<para> <para>
If on, emit WAL-related debugging output. This option is If on, emit WAL-related debugging output. This parameter is
only available if the <symbol>WAL_DEBUG</symbol> macro was only available if the <symbol>WAL_DEBUG</symbol> macro was
defined when <productname>PostgreSQL</productname> was defined when <productname>PostgreSQL</productname> was
compiled. compiled.