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min_parallel_relation_sizeConfigurationReferencemin_parallel_relation_size Query Tuning 9.6 Sets the minimum size of relations to be considered for parallel scan. The default is 8 megabytes (8MB). PostgreSQL describes min_parallel_relatio…Configuration · Query Tuning min_parallel_table_scan_sizeConfigurationReferencemin_parallel_table_scan_size Query Tuning 10 Sets the minimum amount of table data that must be scanned in order for a parallel scan to be considered. For a parallel sequential scan, the amo…Configuration · Query Tuning min_wal_sizeConfigurationReferencemin_wal_size Write-Ahead Log 10 As long as WAL disk usage stays below this setting, old WAL files are always recycled for future use at a checkpoint, rather than removed. This can be used to…Configuration · Write-Ahead Log multixact_member_buffersConfigurationReferencemultixact_member_buffers Resource Usage 17 Specifies the amount of shared memory to use to cache the contents of pg_multixact/members (see Table 65.1). If this value is specified without uni…Configuration · Resource Usage multixact_offset_buffersConfigurationReferencemultixact_offset_buffers Resource Usage 17 Specifies the amount of shared memory to use to cache the contents of pg_multixact/offsets (see Table 65.1). If this value is specified without uni…Configuration · Resource Usage notify_buffersConfigurationReferencenotify_buffers Resource Usage 17 Specifies the amount of shared memory to use to cache the contents of pg_notify (see Table 65.1). If this value is specified without units, it is taken as bl…Configuration · Resource Usage num_os_semaphoresConfigurationReferencenum_os_semaphores Preset Options 18 Reports the number of semaphores that are needed for the server based on the configured number of allowed connections (max_connections), allowed autovacuu…Configuration · Preset Options oauth_validator_librariesConfigurationReferenceoauth_validator_libraries Connections and Authentication 18 The library/libraries to use for validating OAuth connection tokens. If only one validator library is provided, it will be used by…Configuration · Connections and Authentication old_snapshot_thresholdConfigurationReferenceold_snapshot_threshold Resource Usage 10 Sets the minimum time that a snapshot can be used without risk of a snapshot too old error occurring when using the snapshot. This parameter can only…Configuration · Resource Usage operator_precedence_warningConfigurationReferenceoperator_precedence_warning Version and Platform Compatibility 10 When on, the parser will emit a warning for any construct that might have changed meanings since PostgreSQL 9.4 as a result …Configuration · Version and Platform Compatibility output_plugin_librariesConfigurationReferenceoutput_plugin_libraries Replication 14 Lists the libraries installed in dynamic_library_path that are also trusted for use as logical output plugins by replication clients. Any logical decod…Configuration · Replication parallel_leader_participationConfigurationReferenceparallel_leader_participation Resource Usage 11 Allows the leader process to execute the query plan under Gather and Gather Merge nodes instead of waiting for worker processes. The default i…Configuration · Resource Usage parallel_setup_costConfigurationReferenceparallel_setup_cost Query Tuning 10 Sets the planner's estimate of the cost of launching parallel worker processes. The default is 1000. 11 12 13 14 15 16 17 18 19 20 9.6 parallel_setup_cost…Configuration · Query Tuning parallel_tuple_costConfigurationReferenceparallel_tuple_cost Query Tuning 10 Sets the planner's estimate of the cost of transferring one tuple from a parallel worker process to another process. The default is 0.1. 11 12 13 14 15 16…Configuration · Query Tuning password_encryptionConfigurationReferencepassword_encryption Connections and Authentication 10 When a password is specified in CREATE ROLE or ALTER ROLE, this parameter determines the algorithm to use to encrypt the password. The d…Configuration · Connections and Authentication password_expiration_warning_thresholdConfigurationReferencepassword_expiration_warning_threshold Connections and Authentication 19 When this parameter is greater than zero, the server will emit a WARNING upon successful password authentication if le…Configuration · Connections and Authentication pg_trgm.similarity_thresholdConfigurationPG18pg_trgm.similarity_threshold (real) Sets the current similarity threshold that is used by the % operator. The threshold must be between 0 and 1 (default is 0.3).pg_trgm — support for similarity of text using trigram matching › GUC Parameters pg_trgm.strict_word_similarity_thresholdConfigurationPG18pg_trgm.strict_word_similarity_threshold (real) Sets the current strict word similarity threshold that is used by the <<% and %>> operators. The threshold must be between 0 and 1 (default is…pg_trgm — support for similarity of text using trigram matching › GUC Parameters pg_trgm.word_similarity_thresholdConfigurationPG18pg_trgm.word_similarity_threshold (real) Sets the current word similarity threshold that is used by the <% and %> operators. The threshold must be between 0 and 1 (default is 0.6).pg_trgm — support for similarity of text using trigram matching › GUC Parameters plan_cache_modeConfigurationReferenceplan_cache_mode Query Tuning 12 Prepared statements (either explicitly prepared or implicitly generated, for example by PL/pgSQL) can be executed using custom or generic plans. Custom plans …Configuration · Query Tuning plperl.on_initConfigurationPG18plperl.on_init (string) Specifies Perl code to be executed when a Perl interpreter is first initialized, before it is specialized for use by plperl or plperlu. The SPI functions are not avai…PL/Perl Under the Hood › Configuration plperl.on_plperl_initConfigurationPG18plperl.on_plperl_init (string) plperl.on_plperlu_init (string) These parameters specify Perl code to be executed when a Perl interpreter is specialized for plperl or plperlu respectively. Th…PL/Perl Under the Hood › Configuration plperl.on_plperlu_initConfigurationPG18plperl.on_plperl_init (string) plperl.on_plperlu_init (string) These parameters specify Perl code to be executed when a Perl interpreter is specialized for plperl or plperlu respectively. Th…PL/Perl Under the Hood › Configuration plperl.use_strictConfigurationPG18plperl.use_strict (boolean) When set true subsequent compilations of PL/Perl functions will have the strict pragma enabled. This parameter does not affect functions already compiled in the c…PL/Perl Under the Hood › Configuration pltcl.start_procConfigurationPG18pltcl.start_proc (string) This parameter, if set to a nonempty string, specifies the name (possibly schema-qualified) of a parameterless PL/Tcl function that is to be executed whenever a new…PL/Tcl Configuration pltclu.start_procConfigurationPG18pltclu.start_proc (string) This parameter is exactly like pltcl.start_proc, except that it applies to PL/TclU. The referenced function must be written in the pltclu language.PL/Tcl Configuration portConfigurationReferenceport Connections and Authentication 10 The TCP port the server listens on; 5432 by default. Note that the same port number is used for all IP addresses the server listens on. This parameter …Configuration · Connections and Authentication post_auth_delayConfigurationReferencepost_auth_delay Developer Options 10 If nonzero, a delay of this many seconds occurs when a new server process is started, after it conducts the authentication procedure. This is intended to…Configuration · Developer Options postgres_fdw.application_nameConfigurationPG18postgres_fdw.application_name (string) Specifies a value for application_name configuration parameter used when postgres_fdw establishes a connection to a foreign server. This overrides appl…postgres_fdw — access data stored in external PostgreSQL servers › Configuration Parameters pre_auth_delayConfigurationReferencepre_auth_delay Developer Options 10 If nonzero, a delay of this many seconds occurs just after a new server process is forked, before it conducts the authentication procedure. This is intend…Configuration · Developer Options primary_conninfoConfigurationReferenceprimary_conninfo Replication 12 Specifies a connection string to be used for the standby server to connect with a sending server. This string is in the format described in Section 33.1.1. If…Configuration · Replication primary_slot_nameConfigurationReferenceprimary_slot_name Replication 12 Optionally specifies an existing replication slot to be used when connecting to the sending server via streaming replication to control resource removal on t…Configuration · Replication promote_trigger_fileConfigurationReferencepromote_trigger_file Replication 12 Specifies a trigger file whose presence ends recovery in the standby. Even if this value is not set, you can still promote the standby using pg_ctl promot…Configuration · Replication quote_all_identifiersConfigurationReferencequote_all_identifiers Version and Platform Compatibility 10 When the database generates SQL, force all identifiers to be quoted, even if they are not (currently) keywords. This will affect t…Configuration · Version and Platform Compatibility random_page_costConfigurationReferencerandom_page_cost Query Tuning 10 Sets the planner's estimate of the cost of a non-sequentially-fetched disk page. The default is 4.0. This value can be overridden for tables and indexes in a…Configuration · Query Tuning recovery_end_commandConfigurationReferencerecovery_end_command Write-Ahead Log 12 This parameter specifies a shell command that will be executed once only at the end of recovery. This parameter is optional. The purpose of the recove…Configuration · Write-Ahead Log recovery_init_sync_methodConfigurationReferencerecovery_init_sync_method Error Handling 14 When set to fsync, which is the default, PostgreSQL will recursively open and synchronize all files in the data directory before crash recovery be…Configuration · Error Handling recovery_min_apply_delayConfigurationReferencerecovery_min_apply_delay Replication 12 By default, a standby server restores WAL records from the sending server as soon as possible. It may be useful to have a time-delayed copy of the dat…Configuration · Replication recovery_prefetchConfigurationReferencerecovery_prefetch Write-Ahead Log 15 Whether to try to prefetch blocks that are referenced in the WAL that are not yet in the buffer pool, during recovery. Valid values are off, on and try (…Configuration · Write-Ahead Log recovery_targetConfigurationReferencerecovery_target Write-Ahead Log 12 This parameter specifies that recovery should end as soon as a consistent state is reached, i.e., as early as possible. When restoring from an online backu…Configuration · Write-Ahead Log