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bgwriter_flush_afterConfigurationReferencebgwriter_flush_after Resource Usage 10 Whenever more than bgwriter_flush_after bytes have been written by the background writer, attempt to force the OS to issue these writes to the underlyi…Configuration · Resource Usage bgwriter_lru_maxpagesConfigurationReferencebgwriter_lru_maxpages Resource Usage 10 In each round, no more than this many buffers will be written by the background writer. Setting this to zero disables background writing. (Note that c…Configuration · Resource Usage bgwriter_lru_multiplierConfigurationReferencebgwriter_lru_multiplier Resource Usage 10 The number of dirty buffers written in each round is based on the number of new buffers that have been needed by server processes during recent roun…Configuration · Resource Usage block_sizeConfigurationReferenceblock_size Preset Options 10 Reports the size of a disk block. It is determined by the value of BLCKSZ when building the server. The default value is 8192 bytes. The meaning of some configur…Configuration · Preset Options bonjourConfigurationReferencebonjour Connections and Authentication 10 Enables advertising the server's existence via Bonjour. The default is off. This parameter can only be set at server start. 11 12 13 14 15 16 17 18 …Configuration · Connections and Authentication bonjour_nameConfigurationReferencebonjour_name Connections and Authentication 10 Specifies the Bonjour service name. The computer name is used if this parameter is set to the empty string '' (which is the default). This para…Configuration · Connections and Authentication bytea_outputConfigurationReferencebytea_output Client Connection Defaults 10 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…Configuration · Client Connection Defaults check_function_bodiesConfigurationReferencecheck_function_bodies Client Connection Defaults 10 This parameter is normally on. When set to off, it disables validation of the function body string during CREATE FUNCTION. Disabling valid…Configuration · Client Connection Defaults checkpoint_completion_targetConfigurationReferencecheckpoint_completion_target Write-Ahead Log 10 Specifies the target of checkpoint completion, as a fraction of total time between checkpoints. The default is 0.5. This parameter can only be…Configuration · Write-Ahead Log checkpoint_flush_afterConfigurationReferencecheckpoint_flush_after Write-Ahead Log 10 Whenever more than checkpoint_flush_after bytes have been written while performing a checkpoint, attempt to force the OS to issue these writes to th…Configuration · Write-Ahead Log checkpoint_segmentsConfigurationReferencecheckpoint_segments Write-Ahead Log 9.0 Maximum number of log file segments between automatic WAL checkpoints (each segment is normally 16 megabytes). The default is three segments. Increasi…Configuration · Write-Ahead Log checkpoint_timeoutConfigurationReferencecheckpoint_timeout Write-Ahead Log 10 Maximum time between automatic WAL checkpoints, in seconds. The valid range is between 30 seconds and one day. The default is five minutes (5min). Incre…Configuration · Write-Ahead Log checkpoint_warningConfigurationReferencecheckpoint_warning Write-Ahead Log 10 Write a message to the server log if checkpoints caused by the filling of checkpoint segment files happen closer together than this many seconds (which …Configuration · Write-Ahead Log client_connection_check_intervalConfigurationReferenceclient_connection_check_interval Connections and Authentication 14 Sets the time interval between optional checks that the client is still connected, while running queries. The check is perf…Configuration · Connections and Authentication client_encodingConfigurationReferenceclient_encoding Client Connection Defaults 10 Sets the client-side encoding (character set). The default is to use the database encoding. The character sets supported by the PostgreSQL serve…Configuration · Client Connection Defaults client_min_messagesConfigurationReferenceclient_min_messages Client Connection Defaults 10 Controls which message levels are sent to the client. Valid values are DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1, LOG, NOTICE, WARNING, and ERR…Configuration · Client Connection Defaults cluster_nameConfigurationReferencecluster_name Reporting and Logging 10 Sets the cluster name that appears in the process title for all server processes in this cluster. The name can be any string of less than NAMEDATALEN ch…Configuration · Reporting and Logging commit_delayConfigurationReferencecommit_delay Write-Ahead Log 10 commit_delay adds a time delay, measured in microseconds, before a WAL flush is initiated. This can improve group commit throughput by allowing a larger numbe…Configuration · Write-Ahead Log commit_siblingsConfigurationReferencecommit_siblings Write-Ahead Log 10 Minimum number of concurrent open transactions to require before performing the commit_delay delay. A larger value makes it more probable that at least one…Configuration · Write-Ahead Log commit_timestamp_buffersConfigurationReferencecommit_timestamp_buffers Resource Usage 17 Specifies the amount of memory to use to cache the contents of pg_commit_ts (see Table 65.1). If this value is specified without units, it is taken…Configuration · Resource Usage compute_query_idConfigurationReferencecompute_query_id Statistics 14 Enables in-core computation of a query identifier. Query identifiers can be displayed in the pg_stat_activity view, using EXPLAIN, or emitted in the log if con…Configuration · Statistics config_fileConfigurationReferenceconfig_file File Locations 10 Specifies the main server configuration file (customarily called postgresql.conf). This parameter can only be set on the postgres command line. 11 12 13 14 15 1…Configuration · File Locations constraint_exclusionConfigurationReferenceconstraint_exclusion Query Tuning 10 Controls the query planner's use of table constraints to optimize queries. The allowed values of constraint_exclusion are on (examine constraints for all…Configuration · Query Tuning cpu_index_tuple_costConfigurationReferencecpu_index_tuple_cost Query Tuning 10 Sets the planner's estimate of the cost of processing each index entry during an index scan. The default is 0.005. 11 12 13 14 15 16 17 18 19 20 9.0 9.1 …Configuration · Query Tuning cpu_operator_costConfigurationReferencecpu_operator_cost Query Tuning 10 Sets the planner's estimate of the cost of processing each operator or function executed during a query. The default is 0.0025. 11 12 13 14 15 16 17 18 19 2…Configuration · Query Tuning cpu_tuple_costConfigurationReferencecpu_tuple_cost Query Tuning 10 Sets the planner's estimate of the cost of processing each row during a query. The default is 0.01. 11 12 13 14 15 16 17 18 19 20 9.0 9.1 9.2 9.3 9.4 9.5 9.6 c…Configuration · Query Tuning createrole_self_grantConfigurationReferencecreaterole_self_grant Client Connection Defaults 16 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 gra…Configuration · Client Connection Defaults cursor_tuple_fractionConfigurationReferencecursor_tuple_fraction Query Tuning 10 Sets the planner's estimate of the fraction of a cursor's rows that will be retrieved. The default is 0.1. Smaller values of this setting bias the plann…Configuration · Query Tuning custom_variable_classesConfigurationReferencecustom_variable_classes Customized Options 9.0 This variable specifies one or several class names to be used for custom variables, in the form of a comma-separated list. A custom variable is…Configuration · Customized Options data_checksumsConfigurationReferencedata_checksums Preset Options 10 Reports whether data checksums are enabled for this cluster. See data checksums for more information. 11 12 13 14 15 16 17 18 Reports whether data checksums …Configuration · Preset Options data_directoryConfigurationReferencedata_directory File Locations 10 Specifies the directory to use for data storage. This parameter can only be set at server start. 11 12 13 14 15 16 17 18 19 20 9.0 9.1 9.2 9.3 9.4 9.5 9.6 Se…Configuration · File Locations data_directory_modeConfigurationReferencedata_directory_mode Preset Options 11 On Unix systems this parameter reports the permissions of the data directory defined by (data_directory) at startup. (On Microsoft Windows this paramete…Configuration · Preset Options data_sync_retryConfigurationReferencedata_sync_retry Error Handling 10 When set to false, which is the default, PostgreSQL will raise a PANIC-level error on failure to flush modified data files to the filesystem. This causes th…Configuration · Error Handling DateStyleConfigurationReferenceDateStyle Client Connection Defaults 10 Sets the display format for date and time values, as well as the rules for interpreting ambiguous date input values. For historical reasons, this vari…Configuration · Client Connection Defaults db_user_namespaceConfigurationReferencedb_user_namespace Connections and Authentication 10 This parameter enables per-database user names. It is off by default. This parameter can only be set in the postgresql.conf file or on the…Configuration · Connections and Authentication deadlock_timeoutConfigurationReferencedeadlock_timeout Lock Management 10 This is the amount of time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition. The check for deadlock is relative…Configuration · Lock Management debug_assertionsConfigurationReferencedebug_assertions Preset Options 10 Reports whether PostgreSQL has been built with assertions enabled. That is the case if the macro USE_ASSERT_CHECKING is defined when PostgreSQL is built (a…Configuration · Preset Options debug_copy_parse_plan_treesConfigurationReferencedebug_copy_parse_plan_trees Developer Options 18 Enabling this forces all parse and plan trees to be passed through copyObject(), to facilitate catching errors and omissions in copyObject().…Configuration · Developer Options debug_deadlocksConfigurationReferencedebug_deadlocks Developer Options 10 If set, dumps information about all current locks when a deadlock timeout occurs. This parameter is only available if the LOCK_DEBUG macro was defined wh…Configuration · Developer Options debug_discard_cachesConfigurationReferencedebug_discard_caches Developer Options 14 When set to 1, each system catalog cache entry is invalidated at the first possible opportunity, whether or not anything that would render it invali…Configuration · Developer Options