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19.11. Client Connection Defaults #

   19.11.1. Statement Behavior
   19.11.2. Locale and Formatting
   19.11.3. Shared Library Preloading
   19.11.4. Other Defaults

19.11.1. Statement Behavior #

   client_min_messages (enum) #
          Controls which message levels are sent to the client. Valid
          values are DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1, LOG, NOTICE,
          WARNING, and ERROR. Each level includes all the levels that
          follow it. The later the level, the fewer messages are sent. The
          default is NOTICE. Note that LOG has a different rank here than
          in log_min_messages.

          INFO level messages are always sent to the client.

   search_path (string) #
          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 for search_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 have USAGE permission, is
          silently ignored.

          If one of the list items is the special name $user, then the
          schema having the name returned by CURRENT_USER is substituted,
          if there is such a schema and the user has USAGE 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. If
          pg_catalog is not in the path then it will be searched before
          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 alias pg_temp. If it
          is not listed in the path then it is searched first (even before
          pg_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 in
          search_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 of public), 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, see Section 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 the SQL function current_schemas (see Section 9.27). This is
          not quite the same as examining the value of search_path, since
          current_schemas shows how the items appearing in search_path
          were resolved.

   row_security (boolean) #
          This variable controls whether to raise an error in lieu of
          applying a row security policy. When set to on, policies apply
          normally. When set to off, queries fail which would otherwise
          apply at least one policy. The default is on. Change to off
          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 the BYPASSRLS attribute.

          For more information on row security policies, see CREATE
          POLICY.

   default_table_access_method (string) #
          This parameter specifies the default table access method to use
          when creating tables or materialized views if the CREATE command
          does not explicitly specify an access method, or when SELECT ...
          INTO is used, which does not allow specifying a table access
          method. The default is heap.

   default_tablespace (string) #
          This variable specifies the default tablespace in which to
          create objects (tables and indexes) when a CREATE 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 have CREATE 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 if
          default_tablespace has changed since then.

          For more information on tablespaces, see Section 22.6.

   default_toast_compression (enum) #
          This variable sets the default TOAST compression method for
          values of compressible columns. (This can be overridden for
          individual columns by setting the COMPRESSION column option in
          CREATE TABLE or ALTER TABLE.) The supported compression methods
          are pglz and (if PostgreSQL was compiled with --with-lz4) lz4.
          The default is pglz.

   temp_tablespaces (string) #
          This variable specifies tablespaces in which to create temporary
          objects (temp tables and indexes on temp tables) when a CREATE
          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.

          When temp_tablespaces is set interactively, specifying a
          nonexistent tablespace is an error, as is specifying a
          tablespace for which the user does not have CREATE privilege.
          However, when using a previously set value, nonexistent
          tablespaces are ignored, as are tablespaces for which the user
          lacks CREATE privilege. In particular, this rule applies when
          using a value set in postgresql.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 also default_tablespace.

   check_function_bodies (boolean) #
          This parameter is normally on. When set to off, it disables
          validation of the routine body string during CREATE FUNCTION and
          CREATE 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
          to off before loading functions on behalf of other users;
          pg_dump does so automatically.

   default_transaction_isolation (enum) #
          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”.

          Consult Chapter 13 and SET TRANSACTION for more information.

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

          Consult SET TRANSACTION for more information.

   default_transaction_deferrable (boolean) #
          When running at the serializable 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 than
          serializable. The default is off.

          Consult SET TRANSACTION for more information.

   transaction_isolation (enum) #
          This parameter reflects the current transaction's isolation
          level. At the beginning of each transaction, it is set to the
          current value of default_transaction_isolation. Any subsequent
          attempt to change it is equivalent to a SET TRANSACTION command.

   transaction_read_only (boolean) #
          This parameter reflects the current transaction's read-only
          status. At the beginning of each transaction, it is set to the
          current value of default_transaction_read_only. Any subsequent
          attempt to change it is equivalent to a SET TRANSACTION command.

   transaction_deferrable (boolean) #
          This parameter reflects the current transaction's deferrability
          status. At the beginning of each transaction, it is set to the
          current value of default_transaction_deferrable. Any subsequent
          attempt to change it is equivalent to a SET TRANSACTION command.

   session_replication_role (enum) #
          Controls firing of replication-related triggers and rules for
          the current session. Possible values are origin (the default),
          replica and local. Setting this parameter results in discarding
          any previously cached query plans. Only superusers and users
          with the appropriate SET privilege can change this setting.

          The intended use of this setting is that logical replication
          systems set it to replica 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 the ALTER TABLE clauses ENABLE
          TRIGGER and ENABLE RULE for more information.

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

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

   statement_timeout (integer) #
          Abort any statement that takes more than the specified amount of
          time. If log_min_error_statement is set to ERROR 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.

          Setting statement_timeout in postgresql.conf is not recommended
          because it would affect all sessions.

   transaction_timeout (integer) #
          Terminate any session that spans longer than the specified
          amount of time in a transaction. The limit applies both to
          explicit transactions (started with BEGIN) 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.

          If transaction_timeout is shorter or equal to
          idle_in_transaction_session_timeout or statement_timeout then
          the longer timeout is ignored.

          Setting transaction_timeout in postgresql.conf is not
          recommended because it would affect all sessions.

Note

          Prepared transactions are not subject to this timeout.

   lock_timeout (integer) #
          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 as LOCK TABLE, or SELECT FOR
          UPDATE without NOWAIT) 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.

          Unlike statement_timeout, this timeout can only occur while
          waiting for locks. Note that if statement_timeout is nonzero, it
          is rather pointless to set lock_timeout to the same or larger
          value, since the statement timeout would always trigger first.
          If log_min_error_statement is set to ERROR or lower, the
          statement that timed out will be logged.

          Setting lock_timeout in postgresql.conf is not recommended
          because it would affect all sessions.

   idle_in_transaction_session_timeout (integer) #
          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. See Section 24.1 for more details.

   idle_session_timeout (integer) #
          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 than
          idle_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.

   bytea_output (enum) #
          Sets the output format for values of type bytea. Valid values
          are hex (the default) and escape (the traditional PostgreSQL
          format). See Section 8.4 for more information. The bytea type
          always accepts both formats on input, regardless of this
          setting.

   xmlbinary (enum) #
          Sets how binary values are to be encoded in XML. This applies
          for example when bytea values are converted to XML by the
          functions xmlelement or xmlforest. Possible values are base64
          and hex, which are both defined in the XML Schema standard. The
          default is base64. For further information about XML-related
          functions, see Section 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.

   xmloption (enum) #
          Sets whether DOCUMENT or CONTENT is implicit when converting
          between XML and character string values. See Section 8.13 for a
          description of this. Valid values are DOCUMENT and CONTENT. The
          default is CONTENT.

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

SET XML OPTION { DOCUMENT | CONTENT };

          This syntax is also available in PostgreSQL.

   gin_pending_list_limit (integer) #
          Sets the maximum size of a GIN index's pending list, which is
          used when fastupdate 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. See
          Section 65.4.4.1 and Section 65.4.5 for more information.

   createrole_self_grant (string) #
          If a user who has CREATEROLE but not SUPERUSER 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 be set, 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 a CREATEROLE user who is
          not a superuser to automatically inherit, or automatically gain
          the ability to SET ROLE to, any created users. Since a
          CREATEROLE user is always implicitly granted ADMIN OPTION on
          created roles, that user could always execute a GRANT 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 always SET ROLE to any role, and this
          setting can be used to produce a similar behavior for CREATEROLE
          users for users which they create.

   event_triggers (boolean) #
          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 to false. Setting the
          value to true allows all event triggers to fire, this is the
          default value. Only superusers and users with the appropriate
          SET privilege can change this setting.

   restrict_nonsystem_relation_kind (string) #
          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 are
          view and foreign-table.

19.11.2. Locale and Formatting #

   DateStyle (string) #
          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,
          or German) and the input/output specification for year/month/day
          ordering (DMY, MDY, or YMD). These can be set separately or
          together. The keywords Euro and European are synonyms for DMY;
          the keywords US, NonEuro, and NonEuropean are synonyms for MDY.
          See Section 8.5 for more information. The built-in default is
          ISO, MDY, but initdb will initialize the configuration file with
          a setting that corresponds to the behavior of the chosen lc_time
          locale.

   IntervalStyle (enum) #
          Sets the display format for interval values. The value
          sql_standard will produce output matching SQL standard interval
          literals. The value postgres (which is the default) will produce
          output matching PostgreSQL releases prior to 8.4 when the
          DateStyle parameter was set to ISO. The value postgres_verbose
          will produce output matching PostgreSQL releases prior to 8.4
          when the DateStyle parameter was set to non-ISO output. The
          value iso_8601 will produce output matching the time interval
          “format with designators” defined in section 4.4.3.2 of ISO
          8601.

          The IntervalStyle parameter also affects the interpretation of
          ambiguous interval input. See Section 8.5.4 for more
          information.

   TimeZone (string) #
          Sets the time zone for displaying and interpreting time stamps.
          The built-in default is GMT, but that is typically overridden in
          postgresql.conf; initdb will install a setting there
          corresponding to its system environment. See Section 8.5.3 for
          more information.

   timezone_abbreviations (string) #
          Sets the collection of additional time zone abbreviations that
          will be accepted by the server for datetime input (beyond any
          abbreviations defined by the current TimeZone setting). 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. See
          Section B.4 for more information.

   extra_float_digits (integer) #
          This parameter adjusts the number of digits used for textual
          output of floating-point values, including float4, float8, and
          geometric data types.

          If the value is 1 (the default) or above, float values are
          output in shortest-precise format; see Section 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 for float8 values, and 9 for float4 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 or DBL_DIG as
          appropriate) reduced according to the value of this parameter.
          (For example, specifying -1 will cause float4 values to be
          output rounded to 5 significant digits, and float8 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.

Note

          The meaning of this parameter, and its default value, changed in
          PostgreSQL 12; see Section 8.1.3 for further discussion.

   client_encoding (string) #
          Sets the client-side encoding (character set). The default is to
          use the database encoding. The character sets supported by the
          PostgreSQL server are described in Section 23.3.1.

   lc_messages (string) #
          Sets the language in which messages are displayed. Acceptable
          values are system-dependent; see Section 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 appropriate SET privilege can
          change this setting.

   lc_monetary (string) #
          Sets the locale to use for formatting monetary amounts, for
          example with the to_char family of functions. Acceptable values
          are system-dependent; see Section 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.

   lc_numeric (string) #
          Sets the locale to use for formatting numbers, for example with
          the to_char family of functions. Acceptable values are
          system-dependent; see Section 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.

   lc_time (string) #
          Sets the locale to use for formatting dates and times, for
          example with the to_char family of functions. Acceptable values
          are system-dependent; see Section 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.

   icu_validation_level (enum) #
          When ICU locale validation problems are encountered, controls
          which message level is used to report the problem. Valid values
          are DISABLED, DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1, INFO,
          NOTICE, WARNING, ERROR, and LOG.

          If set to DISABLED, does not report validation problems at all.
          Otherwise reports problems at the given message level. The
          default is WARNING.

   default_text_search_config (string) #
          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. See Chapter 12
          for further information. The built-in default is
          pg_catalog.simple, but initdb will initialize the configuration
          file with a setting that corresponds to the chosen lc_ctype
          locale, if a configuration matching that locale can be
          identified.

19.11.3. Shared Library Preloading #

   Several settings are available for preloading shared libraries into the
   server, in order to load additional functionality or achieve
   performance benefits. For example, a setting of '$libdir/mylib' would
   cause mylib.so (or on some platforms, mylib.sl) to be preloaded from
   the installation's standard library directory. The differences between
   the settings are when they take effect and what privileges are required
   to change them.

   PostgreSQL procedural language libraries can be preloaded in this way,
   typically by using the syntax '$libdir/plXXX' where XXX is pgsql, perl,
   tcl, or python.

   Only shared libraries specifically intended to be used with PostgreSQL
   can be loaded this way. Every PostgreSQL-supported library has a “magic
   block” that is checked to guarantee compatibility. For this reason,
   non-PostgreSQL libraries cannot be loaded in this way. You might be
   able to use operating-system facilities such as LD_PRELOAD for that.

   In general, refer to the documentation of a specific module for the
   recommended way to load that module.

   local_preload_libraries (string) #
          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 the
          LOAD 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 the plugins 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 in local_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 explicit LOAD command. To
          that end, it would be typical to set this parameter using the
          PGOPTIONS environment variable on the client or by using ALTER
          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 at session_preload_libraries instead.

   session_preload_libraries (string) #
          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 the
          LOAD 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
          appropriate SET 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 explicit LOAD command being given. For
          example, auto_explain could be enabled for all sessions under a
          given user name by setting this parameter with ALTER 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.

          Unlike shared_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.

   shared_preload_libraries (string) #
          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 the LOAD
          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. Use
          session_preload_libraries for that instead.

Note

          On Windows hosts, preloading a library at server start will not
          reduce the time required to start each new server process; each
          server process will re-load all preload libraries. However,
          shared_preload_libraries is still useful on Windows hosts for
          libraries that need to perform operations at postmaster start
          time.

   jit_provider (string) #
          This variable is the name of the JIT provider library to be used
          (see Section 30.4.2). The default is llvmjit. 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 main PostgreSQL package.

19.11.4. Other Defaults #

   dynamic_library_path (string) #
          If a dynamically loadable module needs to be opened and the file
          name specified in the CREATE FUNCTION or LOAD 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 for dynamic_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-in PostgreSQL package library directory is substituted
          for $libdir; this is where the modules provided by the standard
          PostgreSQL distribution are installed. (Use pg_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 appropriate SET 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 the
          postgresql.conf configuration file.

   extension_control_path (string) #
          A path to search for extensions, specifically extension control
          files (name.control). The remaining extension script and
          secondary control files are then loaded from the same directory
          where the primary control file was found. See Section 36.17.1
          for details.

          The value for extension_control_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 $system, the
          compiled-in PostgreSQL extension directory is substituted for
          $system; this is where the extensions provided by the standard
          PostgreSQL distribution are installed. (Use pg_config --sharedir
          to find out the name of this directory.) For example:

extension_control_path = '/usr/local/share/postgresql:/home/my_project/share:$sy
stem'

          or, in a Windows environment:

extension_control_path = 'C:\tools\postgresql;H:\my_project\share;$system'

          Note that the specified paths elements are expected to have a
          subdirectory extension which will contain the .control and .sql
          files; the extension suffix is automatically appended to each
          path element.

          The default value for this parameter is '$system'. If the value
          is set to an empty string, the default '$system' is also
          assumed.

          If extensions with equal names are present in multiple
          directories in the configured path, only the instance found
          first in the path will be used.

          This parameter can be changed at run time by superusers and
          users with the appropriate SET 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 the
          postgresql.conf configuration file.

          Note that if you set this parameter to be able to load
          extensions from nonstandard locations, you will most likely also
          need to set dynamic_library_path to a correspondent location,
          for example,

extension_control_path = '/usr/local/share/postgresql:$system'
dynamic_library_path = '/usr/local/lib/postgresql:$libdir'

   gin_fuzzy_search_limit (integer) #
          Soft upper limit of the size of the set returned by GIN index
          scans. For more information see Section 65.4.5.