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Architectural FundamentalsManual ChaptersPG181.2. Architectural Fundamentals Before we proceed, you should understand the basic PostgreSQL system architecture. Understanding how the parts of PostgreSQL interact will make this chapter s…Architectural Fundamentals ArchitectureManual ChaptersPG1829.9. Architecture Logical replication is built with an architecture similar to physical streaming replication (see Section 26.2.5). It is implemented by walsender and apply processes. The w…Architecture Archive CallbackManual ChaptersPG1849.2.3. Archive Callback The archive_file_cb callback is called to archive a single WAL file. typedef bool (*ArchiveFileCB) (ArchiveModuleState *state, const char *file, const char *path); I…Archive Callback Archive Module CallbacksManual ChaptersPG1849.2. Archive Module Callbacks The archive callbacks define the actual archiving behavior of the module. The server will call them as required to process each individual WAL file.Archive Module Callbacks Archive ModulesManual ChaptersPG18Chapter 49. Archive Modules PostgreSQL provides infrastructure to create custom modules for continuous archiving (see Section 25.3). While archiving via a shell command (i.e., archive_comman…Archive Modules Archive RecoveryManual ChaptersPG1819.5.5. Archive Recovery This section describes the settings that apply only for the duration of the recovery. They must be reset for any subsequent recovery you wish to perform. “Recovery” …Archive Recovery archive_cleanup_commandConfigurationReferencearchive_cleanup_command Write-Ahead Log 12 This optional parameter specifies a shell command that will be executed at every restartpoint. The purpose of archive_cleanup_command is to provide…Configuration · Write-Ahead Log archive_commandConfigurationReferencearchive_command Write-Ahead Log 10 The local shell command to execute to archive a completed WAL file segment. Any %p in the string is replaced by the path name of the file to archive, and a…Configuration · Write-Ahead Log archive_command ScriptsManual ChaptersPG1825.3.7.3. archive_command Scripts Many people choose to use scripts to define their archive_command, so that their postgresql.conf entry looks very simple: archive_command = 'local_backup_sc…archive_command Scripts archive_libraryConfigurationReferencearchive_library Write-Ahead Log 15 The library to use for archiving completed WAL file segments. If set to an empty string (the default), archiving via shell is enabled, and archive_command …Configuration · Write-Ahead Log archive_modeConfigurationReferencearchive_mode Write-Ahead Log 10 When archive_mode is enabled, completed WAL segments are sent to archive storage by setting archive_command. In addition to off, to disable, there are two mod…Configuration · Write-Ahead Log archive_timeoutConfigurationReferencearchive_timeout Write-Ahead Log 10 The archive_command is only invoked for completed WAL segments. Hence, if your server generates little WAL traffic (or has slack periods where it does so),…Configuration · Write-Ahead Log ArchiveCleanupCommandWait EventsReferenceArchiveCleanupCommand IPC 15 Waiting for archive_cleanup_command to complete. 16 17 18 19 20 Brief rendezvous is normal when every participant continues to advance. Investigate when the same…Wait Events · IPC ArchiveCommandWait EventsReferenceArchiveCommand IPC 15 Waiting for archive_command to complete. 16 17 18 19 20 Brief rendezvous is normal when every participant continues to advance. Investigate when the same phase persists…Wait Events · IPC ArchiverMainWait EventsReferenceArchiverMain Activity 10 Waiting in main loop of the archiver process. 11 12 13 Waiting in main loop of archiver process. 14 15 16 17 18 19 20 This is normally expected idleness for the matc…Wait Events · Activity ArchivingManual ChaptersPG1819.5.3. Archiving archive_mode (enum) # When archive_mode is enabled, completed WAL segments are sent to archive storage by setting archive_command or archive_library. In addition to off, to…Archiving areaFunctionsReferencearea Geometric Functions And Operators 10 area ( object ) → double precision area 11 12 13 Computes area. Available for box, path, circle. A path input must be closed, else NULL is returned.…Functions · Geometric Functions And Operators argmExtensionsExtensionsargmax, argmin, and anyold aggregate functions argm Functions and aggregatesFunctions and aggregates · Extensions ArgumentsManual ChaptersPG18Arguments relname Name of a local relation, for example foo or myschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example "FooBar"; without q…Arguments ArgumentsManual ChaptersPG18Arguments relname Name of a local relation, for example foo or myschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example "FooBar"; without q…Arguments ArgumentsManual ChaptersPG18Arguments relname Name of a local relation, for example foo or myschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example "FooBar"; without q…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use.Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use; omit this parameter to use the unnamed connection. cursorname The name of the cursor to close. fail_on_error If true (the default when omitt…Arguments ArgumentsManual ChaptersPG18Arguments connname The name to use for this connection; if omitted, an unnamed connection is opened, replacing any existing unnamed connection. connstr libpq-style connection info string, fo…Arguments ArgumentsManual ChaptersPG18Arguments connname The name of a named connection to be closed.Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use.Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use; omit this parameter to use the unnamed connection. connstr A connection info string, as previously described for dblink_connect. sql The SQL…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use; omit this parameter to use the unnamed connection. cursorname The name of the cursor to fetch from. howmany The maximum number of rows to re…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use; omit this parameter to use the unnamed connection. connstr A connection info string, as previously described for dblink_connect. sql The SQL…Arguments ArgumentsManual ChaptersPG18Arguments connname The name of a named connection to get notifications on.Arguments ArgumentsManual ChaptersPG18Arguments relname Name of a local relation, for example foo or myschema.mytab. Include double quotes if the name is mixed-case or contains special characters, for example "FooBar"; without q…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use. fail_on_error If true (the default when omitted) then an error thrown on the remote side of the connection causes an error to also be thrown…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to check.Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use; omit this parameter to use the unnamed connection. cursorname The name to assign to this cursor. sql The SELECT statement that you wish to e…Arguments ArgumentsManual ChaptersPG18Arguments connname Name of the connection to use. sql The SQL statement that you wish to execute in the remote database, for example select * from pg_class.Arguments ArgumentsManual ChaptersPG18Arguments void * pointer pointer to existing storage to change Size size size in bytes of storage to allocateArguments ArgumentsManual ChaptersPG18Arguments HeapTuple row row to be copiedArguments ArgumentsManual ChaptersPG18Arguments Portal portal portal containing the cursorArguments ArgumentsManual ChaptersPG18Arguments Portal portal portal containing the cursor bool forward true for fetch forward, false for fetch backward long count maximum number of rows to fetchArguments ArgumentsManual ChaptersPG18Arguments const char * name name of the portalArguments