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Controls whichmessage levels are sent to the client. Valid values areDEBUG5,DEBUG4,DEBUG3,DEBUG2,DEBUG1,LOG,NOTICE,WARNING, andERROR. Each level includes all the levels that follow it. The later the level, the fewer messages are sent. The default isNOTICE. Note thatLOG has a different rank here than inlog_min_messages.

INFO level messages are always sent to the client.

This variable specifies the order in which schemas are searched when an object (table, data type, function, etc.) is referenced by a simple name with no schema specified. When there are objects of identical names in different schemas, the one found first in the search path is used. An object that is not in any of the schemas in the search path can only be referenced by specifying its containing schema with a qualified (dotted) name.

The value forsearch_path must be a comma-separated list of schema names. Any name that is not an existing schema, or is a schema for which the user does not haveUSAGE permission, is silently ignored.

If one of the list items is the special name$user, then the schema having the name returned byCURRENT_USER is substituted, if there is such a schema and the user hasUSAGE permission for it. (If not,$user is ignored.)

The system catalog schema,pg_catalog, is always searched, whether it is mentioned in the path or not. If it is mentioned in the path then it will be searched in the specified order. Ifpg_catalog is not in the path then it will be searchedbefore searching any of the path items.

Likewise, the current session's temporary-table schema,pg_temp_nnn, is always searched if it exists. It can be explicitly listed in the path by using the aliaspg_temp. If it is not listed in the path then it is searched first (even beforepg_catalog). However, the temporary schema is only searched for relation (table, view, sequence, etc.) and data type names. It is never searched for function or operator names.

When objects are created without specifying a particular target schema, they will be placed in the first valid schema named insearch_path. An error is reported if the search path is empty.

The default value for this parameter is"$user", public. This setting supports shared use of a database (where no users have private schemas, and all share use ofpublic), private per-user schemas, and combinations of these. Other effects can be obtained by altering the default search path setting, either globally or per-user.

For more information on schema handling, seeSection 5.10. In particular, the default configuration is suitable only when the database has a single user or a few mutually-trusting users.

The current effective value of the search path can be examined via theSQL functioncurrent_schemas (seeSection 9.27). This is not quite the same as examining the value ofsearch_path, sincecurrent_schemas shows how the items appearing insearch_path were resolved.

This variable controls whether to raise an error in lieu of applying a row security policy. When set toon, policies apply normally. When set tooff, queries fail which would otherwise apply at least one policy. The default ison. Change tooff where limited row visibility could cause incorrect results; for example,pg_dump makes that change by default. This variable has no effect on roles which bypass every row security policy, to wit, superusers and roles with theBYPASSRLS attribute.

For more information on row security policies, seeCREATE POLICY.

This parameter specifies the default table access method to use when creating tables or materialized views if theCREATE command does not explicitly specify an access method, or whenSELECT ... INTO is used, which does not allow specifying a table access method. The default isheap.

This variable specifies the default tablespace in which to create objects (tables and indexes) when aCREATE command does not explicitly specify a tablespace.

The value is either the name of a tablespace, or an empty string to specify using the default tablespace of the current database. If the value does not match the name of any existing tablespace,PostgreSQL will automatically use the default tablespace of the current database. If a nondefault tablespace is specified, the user must haveCREATE privilege for it, or creation attempts will fail.

This variable is not used for temporary tables; for them,temp_tablespaces is consulted instead.

This variable is also not used when creating databases. By default, a new database inherits its tablespace setting from the template database it is copied from.

If this parameter is set to a value other than the empty string when a partitioned table is created, the partitioned table's tablespace will be set to that value, which will be used as the default tablespace for partitions created in the future, even ifdefault_tablespace has changed since then.

For more information on tablespaces, seeSection 22.6.

This variable sets the defaultTOAST compression method for values of compressible columns. (This can be overridden for individual columns by setting theCOMPRESSION column option inCREATE TABLE orALTER TABLE.) The supported compression methods arepglz and (ifPostgreSQL was compiled with--with-lz4)lz4. The default ispglz.

This variable specifies tablespaces in which to create temporary objects (temp tables and indexes on temp tables) when aCREATE command does not explicitly specify a tablespace. Temporary files for purposes such as sorting large data sets are also created in these tablespaces.

The value is a list of names of tablespaces. When there is more than one name in the list,PostgreSQL chooses a random member of the list each time a temporary object is to be created; except that within a transaction, successively created temporary objects are placed in successive tablespaces from the list. If the selected element of the list is an empty string,PostgreSQL will automatically use the default tablespace of the current database instead.

Whentemp_tablespaces is set interactively, specifying a nonexistent tablespace is an error, as is specifying a tablespace for which the user does not haveCREATE privilege. However, when using a previously set value, nonexistent tablespaces are ignored, as are tablespaces for which the user lacksCREATE privilege. In particular, this rule applies when using a value set inpostgresql.conf.

The default value is an empty string, which results in all temporary objects being created in the default tablespace of the current database.

See alsodefault_tablespace.

This parameter is normally on. When set tooff, it disables validation of the routine body string duringCREATE FUNCTION andCREATE PROCEDURE. Disabling validation avoids side effects of the validation process, in particular preventing false positives due to problems such as forward references. Set this parameter tooff before loading functions on behalf of other users;pg_dump does so automatically.

Each SQL transaction has an isolation level, which can be either“read uncommitted”,“read committed”,“repeatable read”, or“serializable”. This parameter controls the default isolation level of each new transaction. The default is“read committed”.

ConsultChapter 13 andSET TRANSACTION for more information.

A read-only SQL transaction cannot alter non-temporary tables. This parameter controls the default read-only status of each new transaction. The default isoff (read/write).

ConsultSET TRANSACTION for more information.

When running at theserializable isolation level, a deferrable read-only SQL transaction may be delayed before it is allowed to proceed. However, once it begins executing it does not incur any of the overhead required to ensure serializability; so serialization code will have no reason to force it to abort because of concurrent updates, making this option suitable for long-running read-only transactions.

This parameter controls the default deferrable status of each new transaction. It currently has no effect on read-write transactions or those operating at isolation levels lower thanserializable. The default isoff.

ConsultSET TRANSACTION for more information.

This parameter reflects the current transaction's isolation level. At the beginning of each transaction, it is set to the current value ofdefault_transaction_isolation. Any subsequent attempt to change it is equivalent to aSET TRANSACTION command.

This parameter reflects the current transaction's read-only status. At the beginning of each transaction, it is set to the current value ofdefault_transaction_read_only. Any subsequent attempt to change it is equivalent to aSET TRANSACTION command.

This parameter reflects the current transaction's deferrability status. At the beginning of each transaction, it is set to the current value ofdefault_transaction_deferrable. Any subsequent attempt to change it is equivalent to aSET TRANSACTION command.

Controls firing of replication-related triggers and rules for the current session. Possible values areorigin (the default),replica andlocal. Setting this parameter results in discarding any previously cached query plans. Only superusers and users with the appropriateSET privilege can change this setting.

The intended use of this setting is that logical replication systems set it toreplica when they are applying replicated changes. The effect of that will be that triggers and rules (that have not been altered from their default configuration) will not fire on the replica. See theALTER TABLE clausesENABLE TRIGGER andENABLE RULE for more information.

PostgreSQL treats the settingsorigin andlocal the same internally. Third-party replication systems may use these two values for their internal purposes, for example usinglocal to designate a session whose changes should not be replicated.

Since foreign keys are implemented as triggers, setting this parameter toreplica also disables all foreign key checks, which can leave data in an inconsistent state if improperly used.

Abort any statement that takes more than the specified amount of time. Iflog_min_error_statement is set toERROR or lower, the statement that timed out will also be logged. If this value is specified without units, it is taken as milliseconds. A value of zero (the default) disables the timeout.

The timeout is measured from the time a command arrives at the server until it is completed by the server. If multiple SQL statements appear in a single simple-query message, the timeout is applied to each statement separately. (PostgreSQL versions before 13 usually treated the timeout as applying to the whole query string.) In extended query protocol, the timeout starts running when any query-related message (Parse, Bind, Execute, Describe) arrives, and it is canceled by completion of an Execute or Sync message.

Settingstatement_timeout inpostgresql.conf is not recommended because it would affect all sessions.

Terminate any session that spans longer than the specified amount of time in a transaction. The limit applies both to explicit transactions (started withBEGIN) and to an implicitly started transaction corresponding to a single statement. If this value is specified without units, it is taken as milliseconds. A value of zero (the default) disables the timeout.

Iftransaction_timeout is shorter or equal toidle_in_transaction_session_timeout orstatement_timeout then the longer timeout is ignored.

Settingtransaction_timeout inpostgresql.conf is not recommended because it would affect all sessions.

Abort any statement that waits longer than the specified amount of time while attempting to acquire a lock on a table, index, row, or other database object. The time limit applies separately to each lock acquisition attempt. The limit applies both to explicit locking requests (such asLOCK TABLE, orSELECT FOR UPDATE withoutNOWAIT) and to implicitly-acquired locks. If this value is specified without units, it is taken as milliseconds. A value of zero (the default) disables the timeout.

Unlikestatement_timeout, this timeout can only occur while waiting for locks. Note that ifstatement_timeout is nonzero, it is rather pointless to setlock_timeout to the same or larger value, since the statement timeout would always trigger first. Iflog_min_error_statement is set toERROR or lower, the statement that timed out will be logged.

Settinglock_timeout inpostgresql.conf is not recommended because it would affect all sessions.

Terminate any session that has been idle (that is, waiting for a client query) within an open transaction for longer than the specified amount of time. If this value is specified without units, it is taken as milliseconds. A value of zero (the default) disables the timeout.

This option can be used to ensure that idle sessions do not hold locks for an unreasonable amount of time. Even when no significant locks are held, an open transaction prevents vacuuming away recently-dead tuples that may be visible only to this transaction; so remaining idle for a long time can contribute to table bloat. SeeSection 24.1 for more details.

Terminate any session that has been idle (that is, waiting for a client query), but not within an open transaction, for longer than the specified amount of time. If this value is specified without units, it is taken as milliseconds. A value of zero (the default) disables the timeout.

Unlike the case with an open transaction, an idle session without a transaction imposes no large costs on the server, so there is less need to enable this timeout thanidle_in_transaction_session_timeout.

Be wary of enforcing this timeout on connections made through connection-pooling software or other middleware, as such a layer may not react well to unexpected connection closure. It may be helpful to enable this timeout only for interactive sessions, perhaps by applying it only to particular users.

VACUUM performs an aggressive scan if the table'spg_class.relfrozenxid field has reached the age specified by this setting. An aggressive scan differs from a regularVACUUM in that it visits every page that might contain unfrozen XIDs or MXIDs, not just those that might contain dead tuples. The default is 150 million transactions. Although users can set this value anywhere from zero to two billion,VACUUM will silently limit the effective value to 95% ofautovacuum_freeze_max_age, so that a periodic manualVACUUM has a chance to run before an anti-wraparound autovacuum is launched for the table. For more information seeSection 24.1.5.

Specifies the cutoff age (in transactions) thatVACUUM should use to decide whether to trigger freezing of pages that have an older XID. The default is 50 million transactions. Although users can set this value anywhere from zero to one billion,VACUUM will silently limit the effective value to half the value ofautovacuum_freeze_max_age, so that there is not an unreasonably short time between forced autovacuums. For more information seeSection 24.1.5.

Specifies the maximum age (in transactions) that a table'spg_class.relfrozenxid field can attain beforeVACUUM takes extraordinary measures to avoid system-wide transaction ID wraparound failure. This isVACUUM's strategy of last resort. The failsafe typically triggers when an autovacuum to prevent transaction ID wraparound has already been running for some time, though it's possible for the failsafe to trigger during anyVACUUM.

When the failsafe is triggered, any cost-based delay that is in effect will no longer be applied, further non-essential maintenance tasks (such as index vacuuming) are bypassed, and anyBuffer Access Strategy in use will be disabled resulting inVACUUM being free to make use of all ofshared buffers.

The default is 1.6 billion transactions. Although users can set this value anywhere from zero to 2.1 billion,VACUUM will silently adjust the effective value to no less than 105% ofautovacuum_freeze_max_age.

VACUUM performs an aggressive scan if the table'spg_class.relminmxid field has reached the age specified by this setting. An aggressive scan differs from a regularVACUUM in that it visits every page that might contain unfrozen XIDs or MXIDs, not just those that might contain dead tuples. The default is 150 million multixacts. Although users can set this value anywhere from zero to two billion,VACUUM will silently limit the effective value to 95% ofautovacuum_multixact_freeze_max_age, so that a periodic manualVACUUM has a chance to run before an anti-wraparound is launched for the table. For more information seeSection 24.1.5.1.

Specifies the cutoff age (in multixacts) thatVACUUM should use to decide whether to trigger freezing of pages with an older multixact ID. The default is 5 million multixacts. Although users can set this value anywhere from zero to one billion,VACUUM will silently limit the effective value to half the value ofautovacuum_multixact_freeze_max_age, so that there is not an unreasonably short time between forced autovacuums. For more information seeSection 24.1.5.1.

Specifies the maximum age (in multixacts) that a table'spg_class.relminmxid field can attain beforeVACUUM takes extraordinary measures to avoid system-wide multixact ID wraparound failure. This isVACUUM's strategy of last resort. The failsafe typically triggers when an autovacuum to prevent transaction ID wraparound has already been running for some time, though it's possible for the failsafe to trigger during anyVACUUM.

When the failsafe is triggered, any cost-based delay that is in effect will no longer be applied, and further non-essential maintenance tasks (such as index vacuuming) are bypassed.

The default is 1.6 billion multixacts. Although users can set this value anywhere from zero to 2.1 billion,VACUUM will silently adjust the effective value to no less than 105% ofautovacuum_multixact_freeze_max_age.

Sets the output format for values of typebytea. Valid values arehex (the default) andescape (the traditional PostgreSQL format). SeeSection 8.4 for more information. Thebytea type always accepts both formats on input, regardless of this setting.

Sets how binary values are to be encoded in XML. This applies for example whenbytea values are converted to XML by the functionsxmlelement orxmlforest. Possible values arebase64 andhex, which are both defined in the XML Schema standard. The default isbase64. For further information about XML-related functions, seeSection 9.15.

The actual choice here is mostly a matter of taste, constrained only by possible restrictions in client applications. Both methods support all possible values, although the hex encoding will be somewhat larger than the base64 encoding.

Sets whetherDOCUMENT orCONTENT is implicit when converting between XML and character string values. SeeSection 8.13 for a description of this. Valid values areDOCUMENT andCONTENT. The default isCONTENT.

According to the SQL standard, the command to set this option is

SET XML OPTION { DOCUMENT | CONTENT };

This syntax is also available in PostgreSQL.

Sets the maximum size of a GIN index's pending list, which is used whenfastupdate is enabled. If the list grows larger than this maximum size, it is cleaned up by moving the entries in it to the index's main GIN data structure in bulk. If this value is specified without units, it is taken as kilobytes. The default is four megabytes (4MB). This setting can be overridden for individual GIN indexes by changing index storage parameters. SeeSection 64.4.4.1 andSection 64.4.5 for more information.

If a user who hasCREATEROLE but notSUPERUSER creates a role, and if this is set to a non-empty value, the newly-created role will be granted to the creating user with the options specified. The value must beset,inherit, or a comma-separated list of these. The default value is an empty string, which disables the feature.

The purpose of this option is to allow aCREATEROLE user who is not a superuser to automatically inherit, or automatically gain the ability toSET ROLE to, any created users. Since aCREATEROLE user is always implicitly grantedADMIN OPTION on created roles, that user could always execute aGRANT statement that would achieve the same effect as this setting. However, it can be convenient for usability reasons if the grant happens automatically. A superuser automatically inherits the privileges of every role and can alwaysSET ROLE to any role, and this setting can be used to produce a similar behavior forCREATEROLE users for users which they create.

Allow temporarily disabling execution of event triggers in order to troubleshoot and repair faulty event triggers. All event triggers will be disabled by setting it tofalse. Setting the value totrue allows all event triggers to fire, this is the default value. Only superusers and users with the appropriateSET privilege can change this setting.

Set relation kinds for which access to non-system relations is prohibited. The value takes the form of a comma-separated list of relation kinds. Currently, the supported relation kinds areview andforeign-table.

Sets the display format for date and time values, as well as the rules for interpreting ambiguous date input values. For historical reasons, this variable contains two independent components: the output format specification (ISO,Postgres,SQL, orGerman) and the input/output specification for year/month/day ordering (DMY,MDY, orYMD). These can be set separately or together. The keywordsEuro andEuropean are synonyms forDMY; the keywordsUS,NonEuro, andNonEuropean are synonyms forMDY. SeeSection 8.5 for more information. The built-in default isISO, MDY, butinitdb will initialize the configuration file with a setting that corresponds to the behavior of the chosenlc_time locale.

Sets the display format for interval values. The valuesql_standard will produce output matchingSQL standard interval literals. The valuepostgres (which is the default) will produce output matchingPostgreSQL releases prior to 8.4 when theDateStyle parameter was set toISO. The valuepostgres_verbose will produce output matchingPostgreSQL releases prior to 8.4 when theDateStyle parameter was set to non-ISO output. The valueiso_8601 will produce output matching the time interval“format with designators” defined in section 4.4.3.2 of ISO 8601.

TheIntervalStyle parameter also affects the interpretation of ambiguous interval input. SeeSection 8.5.4 for more information.

Sets the time zone for displaying and interpreting time stamps. The built-in default isGMT, but that is typically overridden inpostgresql.conf;initdb will install a setting there corresponding to its system environment. SeeSection 8.5.3 for more information.

Sets the collection of time zone abbreviations that will be accepted by the server for datetime input. The default is'Default', which is a collection that works in most of the world; there are also'Australia' and'India', and other collections can be defined for a particular installation. SeeSection B.4 for more information.

This parameter adjusts the number of digits used for textual output of floating-point values, includingfloat4,float8, and geometric data types.

If the value is 1 (the default) or above, float values are output in shortest-precise format; seeSection 8.1.3. The actual number of digits generated depends only on the value being output, not on the value of this parameter. At most 17 digits are required forfloat8 values, and 9 forfloat4 values. This format is both fast and precise, preserving the original binary float value exactly when correctly read. For historical compatibility, values up to 3 are permitted.

If the value is zero or negative, then the output is rounded to a given decimal precision. The precision used is the standard number of digits for the type (FLT_DIG orDBL_DIG as appropriate) reduced according to the value of this parameter. (For example, specifying -1 will causefloat4 values to be output rounded to 5 significant digits, andfloat8 values rounded to 14 digits.) This format is slower and does not preserve all the bits of the binary float value, but may be more human-readable.

Sets the client-side encoding (character set). The default is to use the database encoding. The character sets supported by thePostgreSQL server are described inSection 23.3.1.

Sets the language in which messages are displayed. Acceptable values are system-dependent; seeSection 23.1 for more information. If this variable is set to the empty string (which is the default) then the value is inherited from the execution environment of the server in a system-dependent way.

On some systems, this locale category does not exist. Setting this variable will still work, but there will be no effect. Also, there is a chance that no translated messages for the desired language exist. In that case you will continue to see the English messages.

Only superusers and users with the appropriateSET privilege can change this setting.

Sets the locale to use for formatting monetary amounts, for example with theto_char family of functions. Acceptable values are system-dependent; seeSection 23.1 for more information. If this variable is set to the empty string (which is the default) then the value is inherited from the execution environment of the server in a system-dependent way.

Sets the locale to use for formatting numbers, for example with theto_char family of functions. Acceptable values are system-dependent; seeSection 23.1 for more information. If this variable is set to the empty string (which is the default) then the value is inherited from the execution environment of the server in a system-dependent way.

Sets the locale to use for formatting dates and times, for example with theto_char family of functions. Acceptable values are system-dependent; seeSection 23.1 for more information. If this variable is set to the empty string (which is the default) then the value is inherited from the execution environment of the server in a system-dependent way.

When ICU locale validation problems are encountered, controls whichmessage level is used to report the problem. Valid values areDISABLED,DEBUG5,DEBUG4,DEBUG3,DEBUG2,DEBUG1,INFO,NOTICE,WARNING,ERROR, andLOG.

If set toDISABLED, does not report validation problems at all. Otherwise reports problems at the given message level. The default isWARNING.

Selects the text search configuration that is used by those variants of the text search functions that do not have an explicit argument specifying the configuration. SeeChapter 12 for further information. The built-in default ispg_catalog.simple, butinitdb will initialize the configuration file with a setting that corresponds to the chosenlc_ctype locale, if a configuration matching that locale can be identified.

This variable specifies one or more shared libraries that are to be preloaded at connection start. It contains a comma-separated list of library names, where each name is interpreted as for theLOAD command. Whitespace between entries is ignored; surround a library name with double quotes if you need to include whitespace or commas in the name. The parameter value only takes effect at the start of the connection. Subsequent changes have no effect. If a specified library is not found, the connection attempt will fail.

This option can be set by any user. Because of that, the libraries that can be loaded are restricted to those appearing in theplugins subdirectory of the installation's standard library directory. (It is the database administrator's responsibility to ensure that only“safe” libraries are installed there.) Entries inlocal_preload_libraries can specify this directory explicitly, for example$libdir/plugins/mylib, or just specify the library name —mylib would have the same effect as$libdir/plugins/mylib.

The intent of this feature is to allow unprivileged users to load debugging or performance-measurement libraries into specific sessions without requiring an explicitLOAD command. To that end, it would be typical to set this parameter using thePGOPTIONS environment variable on the client or by usingALTER ROLE SET.

However, unless a module is specifically designed to be used in this way by non-superusers, this is usually not the right setting to use. Look atsession_preload_libraries instead.

This variable specifies one or more shared libraries that are to be preloaded at connection start. It contains a comma-separated list of library names, where each name is interpreted as for theLOAD command. Whitespace between entries is ignored; surround a library name with double quotes if you need to include whitespace or commas in the name. The parameter value only takes effect at the start of the connection. Subsequent changes have no effect. If a specified library is not found, the connection attempt will fail. Only superusers and users with the appropriateSET privilege can change this setting.

The intent of this feature is to allow debugging or performance-measurement libraries to be loaded into specific sessions without an explicitLOAD command being given. For example,auto_explain could be enabled for all sessions under a given user name by setting this parameter withALTER ROLE SET. Also, this parameter can be changed without restarting the server (but changes only take effect when a new session is started), so it is easier to add new modules this way, even if they should apply to all sessions.

Unlikeshared_preload_libraries, there is no large performance advantage to loading a library at session start rather than when it is first used. There is some advantage, however, when connection pooling is used.

This variable specifies one or more shared libraries to be preloaded at server start. It contains a comma-separated list of library names, where each name is interpreted as for theLOAD command. Whitespace between entries is ignored; surround a library name with double quotes if you need to include whitespace or commas in the name. This parameter can only be set at server start. If a specified library is not found, the server will fail to start.

Some libraries need to perform certain operations that can only take place at postmaster start, such as allocating shared memory, reserving light-weight locks, or starting background workers. Those libraries must be loaded at server start through this parameter. See the documentation of each library for details.

Other libraries can also be preloaded. By preloading a shared library, the library startup time is avoided when the library is first used. However, the time to start each new server process might increase slightly, even if that process never uses the library. So this parameter is recommended only for libraries that will be used in most sessions. Also, changing this parameter requires a server restart, so this is not the right setting to use for short-term debugging tasks, say. Usesession_preload_libraries for that instead.

This variable is the name of the JIT provider library to be used (seeSection 30.4.2). The default isllvmjit. This parameter can only be set at server start.

If set to a non-existent library,JIT will not be available, but no error will be raised. This allows JIT support to be installed separately from the mainPostgreSQL package.

If a dynamically loadable module needs to be opened and the file name specified in theCREATE FUNCTION orLOAD command does not have a directory component (i.e., the name does not contain a slash), the system will search this path for the required file.

The value fordynamic_library_path must be a list of absolute directory paths separated by colons (or semi-colons on Windows). If a list element starts with the special string$libdir, the compiled-inPostgreSQL package library directory is substituted for$libdir; this is where the modules provided by the standardPostgreSQL distribution are installed. (Usepg_config --pkglibdir to find out the name of this directory.) For example:

dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir'

or, in a Windows environment:

dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'

The default value for this parameter is'$libdir'. If the value is set to an empty string, the automatic path search is turned off.

This parameter can be changed at run time by superusers and users with the appropriateSET privilege, but a setting done that way will only persist until the end of the client connection, so this method should be reserved for development purposes. The recommended way to set this parameter is in thepostgresql.conf configuration file.

Soft upper limit of the size of the set returned by GIN index scans. For more information seeSection 64.4.5.