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timing_clock_sourceConfigurationReferencetiming_clock_source Resource Usage 19 Selects the method for making timing measurements using the OS or specialized CPU instructions. Possible values are: auto (automatically chooses TSC clo…Configuration · Resource Usage trace_connection_negotiationConfigurationReferencetrace_connection_negotiation Developer Options 17 18 19 trace_connection_negotiation logs details from the pre-authentication connection negotiation path, providing evidence for protocol, en…Configuration · Developer Options trace_lock_oidminConfigurationReferencetrace_lock_oidmin Developer Options 10 If set, do not trace locks for tables below this OID (used to avoid output on system tables). This parameter is only available if the LOCK_DEBUG macro …Configuration · Developer Options trace_lock_tableConfigurationReferencetrace_lock_table Developer Options 10 Unconditionally trace locks on this table (OID). This parameter is only available if the LOCK_DEBUG macro was defined when PostgreSQL was compiled. 11 1…Configuration · Developer Options trace_locksConfigurationReferencetrace_locks Developer Options 10 If on, emit information about lock usage. Information dumped includes the type of lock operation, the type of lock and the unique identifier of the object be…Configuration · Developer Options trace_lwlocksConfigurationReferencetrace_lwlocks Developer Options 10 If on, emit information about lightweight lock usage. Lightweight locks are intended primarily to provide mutual exclusion of access to shared-memory data …Configuration · Developer Options trace_notifyConfigurationReferencetrace_notify Developer Options 10 Generates a great amount of debugging output for the LISTEN and NOTIFY commands. client_min_messages or log_min_messages must be DEBUG1 or lower to send thi…Configuration · Developer Options trace_recovery_messagesConfigurationReferencetrace_recovery_messages Developer Options 10 Enables logging of recovery-related debugging output that otherwise would not be logged. This parameter allows the user to override the normal se…Configuration · Developer Options trace_sortConfigurationReferencetrace_sort Developer Options 10 If on, emit information about resource usage during sort operations. This parameter is only available if the TRACE_SORT macro was defined when PostgreSQL was …Configuration · Developer Options trace_userlocksConfigurationReferencetrace_userlocks Developer Options 10 If on, emit information about user lock usage. Output is the same as for trace_locks, only for advisory locks. This parameter is only available if the LO…Configuration · Developer Options track_activitiesConfigurationReferencetrack_activities Statistics 10 Enables the collection of information on the currently executing command of each session, along with the time when that command began execution. This parameter…Configuration · Statistics track_activity_query_sizeConfigurationReferencetrack_activity_query_size Statistics 10 Specifies the number of bytes reserved to track the currently executing command for each active session, for the pg_stat_activity.query field. The def…Configuration · Statistics track_commit_timestampConfigurationReferencetrack_commit_timestamp Replication 10 Record commit time of transactions. This parameter can only be set in postgresql.conf file or on the server command line. The default value is off. 11 1…Configuration · Replication track_cost_delay_timingConfigurationReferencetrack_cost_delay_timing Statistics 18 Enables timing of cost-based vacuum delay (see Section 19.10.2). This parameter is off by default, as it will repeatedly query the operating system for …Configuration · Statistics track_countsConfigurationReferencetrack_counts Statistics 10 Enables collection of statistics on database activity. This parameter is on by default, because the autovacuum daemon needs the collected information. Only superus…Configuration · Statistics track_functionsConfigurationReferencetrack_functions Statistics 10 Enables tracking of function call counts and time used. Specify pl to track only procedural-language functions, all to also track SQL and C language functions. …Configuration · Statistics track_io_timingConfigurationReferencetrack_io_timing Statistics 10 Enables timing of database I/O calls. This parameter is off by default, because it will repeatedly query the operating system for the current time, which may ca…Configuration · Statistics track_wal_io_timingConfigurationReferencetrack_wal_io_timing Statistics 14 Enables timing of WAL I/O calls. This parameter is off by default, as it will repeatedly query the operating system for the current time, which may cause si…Configuration · Statistics transaction_buffersConfigurationReferencetransaction_buffers Resource Usage 17 Specifies the amount of shared memory to use to cache the contents of pg_xact (see Table 65.1). If this value is specified without units, it is taken as…Configuration · Resource Usage transaction_deferrableConfigurationReferencetransaction_deferrable Client Connection Defaults 10 This parameter reflects the current transaction's deferrability status. At the beginning of each transaction, it is set to the current va…Configuration · Client Connection Defaults transaction_isolationConfigurationReferencetransaction_isolation Client Connection Defaults 10 This parameter reflects the current transaction's isolation level. At the beginning of each transaction, it is set to the current value of…Configuration · Client Connection Defaults transaction_read_onlyConfigurationReferencetransaction_read_only Client Connection Defaults 10 This parameter reflects the current transaction's read-only status. At the beginning of each transaction, it is set to the current value o…Configuration · Client Connection Defaults transaction_timeoutConfigurationReferencetransaction_timeout Client Connection Defaults 17 Terminate any session that spans longer than the specified amount of time in a transaction. The limit applies both to explicit transactions …Configuration · Client Connection Defaults transform_null_equalsConfigurationReferencetransform_null_equals Version and Platform Compatibility 10 When on, expressions of the form expr = NULL (or NULL = expr) are treated as expr IS NULL, that is, they return true if expr evalu…Configuration · Version and Platform Compatibility unix_socket_directoriesConfigurationReferenceunix_socket_directories Connections and Authentication 10 Specifies the directory of the Unix-domain socket(s) on which the server is to listen for connections from client applications. Mult…Configuration · Connections and Authentication unix_socket_directoryConfigurationReferenceunix_socket_directory Connections and Authentication 9.0 Specifies the directory of the Unix-domain socket on which the server is to listen for connections from client applications. The defa…Configuration · Connections and Authentication unix_socket_groupConfigurationReferenceunix_socket_group Connections and Authentication 10 Sets the owning group of the Unix-domain socket(s). (The owning user of the sockets is always the user that starts the server.) In combina…Configuration · Connections and Authentication unix_socket_permissionsConfigurationReferenceunix_socket_permissions Connections and Authentication 10 Sets the access permissions of the Unix-domain socket(s). Unix-domain sockets use the usual Unix file system permission set. The par…Configuration · Connections and Authentication update_process_titleConfigurationReferenceupdate_process_title Reporting and Logging 10 Enables updating of the process title every time a new SQL command is received by the server. This setting defaults to on on most platforms, but…Configuration · Reporting and Logging vacuum_buffer_usage_limitConfigurationReferencevacuum_buffer_usage_limit Resource Usage 16 Specifies the size of the Buffer Access Strategy used by the VACUUM and ANALYZE commands. A setting of 0 will allow the operation to use any numbe…Configuration · Resource Usage vacuum_cleanup_index_scale_factorConfigurationReferencevacuum_cleanup_index_scale_factor Client Connection Defaults 11 Specifies the fraction of the total number of heap tuples counted in the previous statistics collection that can be inserted w…Configuration · Client Connection Defaults vacuum_cost_delayConfigurationReferencevacuum_cost_delay Vacuuming 10 The length of time, in milliseconds, that the process will sleep when the cost limit has been exceeded. The default value is zero, which disables the cost-base…Configuration · Vacuuming vacuum_cost_limitConfigurationReferencevacuum_cost_limit Vacuuming 10 The accumulated cost that will cause the vacuuming process to sleep. The default value is 200. 11 12 13 14 15 16 17 This is the accumulated cost that will caus…Configuration · Vacuuming vacuum_cost_page_dirtyConfigurationReferencevacuum_cost_page_dirty Vacuuming 10 The estimated cost charged when vacuum modifies a block that was previously clean. It represents the extra I/O required to flush the dirty block out to di…Configuration · Vacuuming vacuum_cost_page_hitConfigurationReferencevacuum_cost_page_hit Vacuuming 10 The estimated cost for vacuuming a buffer found in the shared buffer cache. It represents the cost to lock the buffer pool, lookup the shared hash table and…Configuration · Vacuuming vacuum_cost_page_missConfigurationReferencevacuum_cost_page_miss Vacuuming 10 The estimated cost for vacuuming a buffer that has to be read from disk. This represents the effort to lock the buffer pool, lookup the shared hash table, …Configuration · Vacuuming vacuum_defer_cleanup_ageConfigurationReferencevacuum_defer_cleanup_age Replication 10 Specifies the number of transactions by which VACUUM and HOT updates will defer cleanup of dead row versions. The default is zero transactions, meanin…Configuration · Replication vacuum_failsafe_ageConfigurationReferencevacuum_failsafe_age Vacuuming 14 Specifies the maximum age (in transactions) that a table's pg_class.relfrozenxid field can attain before VACUUM takes extraordinary measures to avoid system-…Configuration · Vacuuming vacuum_freeze_min_ageConfigurationReferencevacuum_freeze_min_age Vacuuming 10 Specifies the cutoff age (in transactions) that VACUUM should use to decide whether to freeze row versions while scanning a table. The default is 50 millio…Configuration · Vacuuming vacuum_freeze_table_ageConfigurationReferencevacuum_freeze_table_age Vacuuming 10 VACUUM performs an aggressive scan if the table's pg_class.relfrozenxid field has reached the age specified by this setting. An aggressive scan differs f…Configuration · Vacuuming