<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.280 2010/05/31 15:50:48 momjian Exp $ -->

<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.281 2010/06/15 07:52:10 itagaki Exp $ -->

<chapter Id="runtime-config">

<title>Server Configuration</title>

</listitem>

</varlistentry>

<varlistentry id="guc-vacuum-defer-cleanup-age" xreflabel="vacuum_defer_cleanup_age">

<term><varname>vacuum_defer_cleanup_age</varname> (<type>integer</type>)</term>

<indexterm>

<primary><varname>vacuum_defer_cleanup_age</> configuration parameter</primary>

</indexterm>

<listitem>

<para>

Specifies the number of transactions by which <command>VACUUM</> and

<acronym>HOT</> updates will defer cleanup of dead row versions. The

default is 0 transactions, meaning that dead row versions will be

removed as soon as possible. You may wish to set this to a non-zero

value when planning or maintaining a <xref linkend="hot-standby">

configuration. The recommended value is <literal>0</> unless you have

clear reason to increase it. The purpose of the parameter is to

allow the user to specify an approximate time delay before cleanup

occurs. However, it should be noted that there is no direct link with

any specific time delay and so the results will be application and

installation specific, as well as variable over time, depending upon

the transaction rate (of writes only).

</para>

</listitem>

</varlistentry>

</variablelist>

</sect2>

</sect1>

</listitem>

</varlistentry>

<varlistentry id="guc-vacuum-defer-cleanup-age" xreflabel="vacuum_defer_cleanup_age">

<term><varname>vacuum_defer_cleanup_age</varname> (<type>integer</type>)</term>

<indexterm>

<primary><varname>vacuum_defer_cleanup_age</> configuration parameter</primary>

</indexterm>

<listitem>

<para>

Specifies the number of transactions by which <command>VACUUM</> and

<acronym>HOT</> updates will defer cleanup of dead row versions. The

default is 0 transactions, meaning that dead row versions will be

removed as soon as possible. You may wish to set this to a non-zero

value when planning or maintaining a <xref linkend="hot-standby">

configuration. The recommended value is <literal>0</> unless you have

clear reason to increase it. The purpose of the parameter is to

allow the user to specify an approximate time delay before cleanup

occurs. However, it should be noted that there is no direct link with

any specific time delay and so the results will be application and

installation specific, as well as variable over time, depending upon

the transaction rate (of writes only).

</para>

</listitem>

</varlistentry>

<varlistentry id="guc-bytea-output" xreflabel="bytea_output">

<term><varname>bytea_output</varname> (<type>enum</type>)</term>

<indexterm>

gettext_noop("Resource Usage / Memory"),

gettext_noop("Resource Usage / Kernel Resources"),

gettext_noop("Resource Usage / Cost-Based Vacuum Delay"),

gettext_noop("Resource Usage / Background Writer"),

gettext_noop("Resource Usage / Asynchronous Behavior"),

gettext_noop("Write-Ahead Log"),

gettext_noop("Write-Ahead Log / Settings"),

gettext_noop("Write-Ahead Log / Checkpoints"),

gettext_noop("Write-Ahead Log / Archiving"),

gettext_noop("Write-Ahead Log / Replication"),

gettext_noop("Write-Ahead Log / Streaming Replication"),

gettext_noop("Write-Ahead Log / Standby Servers"),

gettext_noop("Query Tuning"),

},

{

{"archive_mode",PGC_POSTMASTER,WAL_SETTINGS,

{"archive_mode",PGC_POSTMASTER,WAL_ARCHIVING,

gettext_noop("Allows archiving of WAL files using archive_command."),

},

},

{

{"hot_standby",PGC_POSTMASTER,WAL_SETTINGS,

{"hot_standby",PGC_POSTMASTER,WAL_STANDBY_SERVERS,

gettext_noop("Allows connections and queries during recovery."),

},

staticstructconfig_intConfigureNamesInt[]=

{

{

{"archive_timeout",PGC_SIGHUP,WAL_SETTINGS,

{"archive_timeout",PGC_SIGHUP,WAL_ARCHIVING,

gettext_noop("Forces a switch to the next xlog file if a "

"new file has not been started within N seconds."),

NULL,

},

{

{"max_standby_delay",PGC_SIGHUP,WAL_SETTINGS,

{"max_standby_delay",PGC_SIGHUP,WAL_STANDBY_SERVERS,

gettext_noop("Sets the maximum delay to avoid conflict processing on hot standby servers."),

NULL,

},

{

{"vacuum_cost_page_hit",PGC_USERSET,RESOURCES,

{"vacuum_cost_page_hit",PGC_USERSET,RESOURCES_VACUUM_DELAY,

gettext_noop("Vacuum cost for a page found in the buffer cache."),

},

},

{

{"vacuum_cost_page_miss",PGC_USERSET,RESOURCES,

{"vacuum_cost_page_miss",PGC_USERSET,RESOURCES_VACUUM_DELAY,

gettext_noop("Vacuum cost for a page not found in the buffer cache."),

},

},

{

{"vacuum_cost_page_dirty",PGC_USERSET,RESOURCES,

{"vacuum_cost_page_dirty",PGC_USERSET,RESOURCES_VACUUM_DELAY,

gettext_noop("Vacuum cost for a page dirtied by vacuum."),

},

},

{

{"vacuum_cost_limit",PGC_USERSET,RESOURCES,

{"vacuum_cost_limit",PGC_USERSET,RESOURCES_VACUUM_DELAY,

gettext_noop("Vacuum cost amount available before napping."),

},

},

{

{"vacuum_cost_delay",PGC_USERSET,RESOURCES,

{"vacuum_cost_delay",PGC_USERSET,RESOURCES_VACUUM_DELAY,

gettext_noop("Vacuum cost delay in milliseconds."),

NULL,

{

{"max_prepared_transactions",PGC_POSTMASTER,RESOURCES,

{"max_prepared_transactions",PGC_POSTMASTER,RESOURCES_MEM,

gettext_noop("Sets the maximum number of simultaneously prepared transactions."),

},

},

{

{"vacuum_defer_cleanup_age",PGC_USERSET,CLIENT_CONN_STATEMENT,

{"vacuum_defer_cleanup_age",PGC_USERSET,WAL_STANDBY_SERVERS,

gettext_noop("Age by which VACUUM and HOT cleanup should be deferred, if any."),

},

},

{

{"bgwriter_delay",PGC_SIGHUP,RESOURCES,

{"bgwriter_delay",PGC_SIGHUP,RESOURCES_BGWRITER,

gettext_noop("Background writer sleep time between rounds."),

NULL,

},

{

{"bgwriter_lru_maxpages",PGC_SIGHUP,RESOURCES,

{"bgwriter_lru_maxpages",PGC_SIGHUP,RESOURCES_BGWRITER,

gettext_noop("Background writer maximum number of LRU pages to flush per round."),

},

PGC_INTERNAL,

RESOURCES,

RESOURCES_ASYNCHRONOUS,

gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),

gettext_noop("For RAID arrays, this should be approximately the number of drive spindles in the array.")

},

},

{

{"bgwriter_lru_multiplier",PGC_SIGHUP,RESOURCES,

{"bgwriter_lru_multiplier",PGC_SIGHUP,RESOURCES_BGWRITER,

gettext_noop("Multiple of the average buffer usage to free per round."),

},

staticstructconfig_stringConfigureNamesString[]=

{

{

{"archive_command",PGC_SIGHUP,WAL_SETTINGS,

{"archive_command",PGC_SIGHUP,WAL_ARCHIVING,

gettext_noop("Sets the shell command that will be called to archive a WAL file."),

},

{

{"application_name",PGC_USERSET,LOGGING,

{"application_name",PGC_USERSET,LOGGING_WHAT,

gettext_noop("Sets the application name to be reported in statistics and logs."),

NULL,

GUC_IS_NAME |GUC_REPORT |GUC_NOT_IN_SAMPLE

#archive_timeout = 0# force a logfile segment switch after this

# number of seconds; 0 disables

# - Hot Standby -

# - Streaming Replication -

#max_wal_senders = 0# max number of walsender processes

#wal_sender_delay = 200ms# 1-10000 milliseconds

#wal_keep_segments = 0# in logfile segments, 16MB each; 0 disables

# - Standby Servers -

#hot_standby = off# allows queries during recovery

#max_standby_delay = 30s# max acceptable lag to allow queries to

# complete without conflict; -1 means forever

#vacuum_defer_cleanup_age = 0# num transactions by which cleanup is deferred

# - Replication -

#max_wal_senders = 0# max number of walsender processes

#wal_sender_delay = 200ms# 1-10000 milliseconds

#wal_keep_segments = 0# in logfile segments, 16MB each; 0 disables

#------------------------------------------------------------------------------

# QUERY TUNING

RESOURCES,

RESOURCES_MEM,

RESOURCES_KERNEL,

RESOURCES_VACUUM_DELAY,

RESOURCES_BGWRITER,

RESOURCES_ASYNCHRONOUS,

WAL,

WAL_SETTINGS,

WAL_CHECKPOINTS,

WAL_ARCHIVING,

WAL_REPLICATION,

WAL_STANDBY_SERVERS,

QUERY_TUNING,

QUERY_TUNING_METHOD,

QUERY_TUNING_COST,