Search PostgreSQL documentation

log_fdwExtensionsExtensionsForeign data wrappers · Extensionsforeign-data wrapper for Postgres log file access log_fdw Foreign data wrappers log_functionsExtensionsExtensionsMonitoring · ExtensionsModule to log functions function log stored procedure log_functions Monitoring logerrorsExtensionsExtensionsSecurity · ExtensionsFunction for collecting statistics about messages in logfile logerrors Security logfmtExtensionsExtensionsMonitoring · Extensionslog collector log logging monitoring logfmt Monitoring loggingExtensionsExtensionsAdministration · ExtensionsAdministrative C function to enable or disable logging mode on relations. admin unlogged wal logging Administration Logical DecodingManual ChaptersPG18Logical Decoding Conceptsis the process of extracting all persistent changes to a database's tables into a coherent, easy to understand format which can be interpreted without detailed knowledge of the database's in… Logical DecodingManual ChaptersPG18PostgreSQL provides infrastructure to stream the modifications performed via SQL to external consumers. This functionality can be used for a variety of purposes, including replication soluti… Logical Decoding ConceptsManual ChaptersPG18 Logical Decoding ExamplesManual ChaptersPG18The following example demonstrates controlling logical decoding using the SQL interface. Before you can use logical decoding, you must set wal_level to logical and max_replication_slots to a… Logical Decoding Output PluginsManual ChaptersPG18An example output plugin can be found in the contrib/test_decoding subdirectory of the PostgreSQL source tree. Logical Decoding Output WritersManual ChaptersPG18It is possible to add more output methods for logical decoding. For details, see src/backend/replication/logical/logicalfuncs.c. Essentially, three functions need to be provided: one to read… Logical Decoding SQL InterfaceManual ChaptersPG18See Section 9.28.6 for detailed documentation on the SQL-level API for interacting with logical decoding. Synchronous replication (see Section 26.2.8) is only supported on replication slots … Logical OperatorsManual ChaptersPG18The usual logical operators are available: boolean AND boolean → boolean boolean OR boolean → boolean NOT boolean → boolean SQL uses a three-valued logic system with true, false, and null, w… Logical ReplicationManual ChaptersPG18is a method of replicating data objects and their changes, based upon their replication identity (usually a primary key). We use the term logical in contrast to physical replication, which u… Logical ReplicationManual ChaptersPG18Release 18Allow the values of generated columns to be logically replicated (Shubham Khanna, Vignesh C, Zhijie Hou, Shlok Kyal, Peter Smith) § § § § If the publication specifies a column list, all spec… Logical Replication ApplicationsManual ChaptersPG18Release 18Add pg_createsubscriber option --all to create logical replicas for all databases (Shubham Khanna) § Add pg_createsubscriber option --clean to remove publications (Shubham Khanna) § § Add pg… Logical Replication FailoverManual ChaptersPG18To allow subscriber nodes to continue replicating data from the publisher node even when the publisher node goes down, there must be a physical standby corresponding to the publisher node. T… Logical Replication Message FormatsManual ChaptersPG18This section describes the detailed format of each logical replication message. These messages are either returned by the replication slot SQL interface or are sent by a walsender. In the ca… Logical Replication Protocol Message FlowManual ChaptersPG18Logical Streaming Replication ProtocolWith the exception of the START_REPLICATION command and the replay progress messages, all information flows only from the backend to the frontend. The logical replication protocol sends indi… Logical Replication Protocol MessagesManual ChaptersPG18Logical Streaming Replication ProtocolThe individual protocol messages are discussed in the following subsections. Individual messages are described in Section 54.9. All top-level protocol messages begin with a message type byte… Logical Streaming Replication ParametersManual ChaptersPG18Logical Streaming Replication ProtocolUsing the START_REPLICATION command, pgoutput accepts the following options: proto_version Protocol version. Currently versions 1, 2, 3, and 4 are supported. A valid version is required. Ver… Logical Streaming Replication ProtocolManual ChaptersPG18This section describes the logical replication protocol, which is the message flow started by the START_REPLICATION SLOT slot_name LOGICAL replication command. The logical streaming replicat… logical_ddlExtensionsExtensionsReplication and streams · ExtensionsReplicate supported DDL changes over PostgreSQL logical replication logical_ddl Replication and streams loginManual ChaptersPG18Overview of Event Trigger BehaviorThe login event occurs when an authenticated user logs into the system. Any bug in a trigger procedure for this event may prevent successful login to the system. Such bugs may be worked arou… login_hookExtensionsExtensionsSecurity · Extensionshook to execute login_hook.login() at login time login_hook Security login_refuseExtensionsExtensionsSecurity · ExtensionsAuthentication hook that temporarily refuses logins after repeated failures authentication login security login_refuse Security loginfoExtensionsExtensionsMonitoring · ExtensionsFunctions and views for PostgreSQL to query the postgres log logging monitoring observability loginfo Monitoring loglog_counterExtensionsExtensionsFunctions and aggregates · ExtensionsAggregation functions and data type for distinct estimation based on LogLog. aggregate count distinct estimate loglog distinct_estimators Functions and aggregates lolorExtensionsExtensionsReplication and streams · ExtensionsLogical-replication-friendly replacement for PostgreSQL large objects fork pgedge lolor Replication and streams londisteExtensionsExtensionsReplication and streams · Extensionsreplication support code logical-replication queue replication londiste Replication and streams longitudeFunctionsPG18earthdistance — calculate great-circle distances › Cube-Based Earth Distances( earth ) → float8 Returns the longitude in degrees of a point on the surface of the Earth. LOOPManual ChaptersPG18Control Structures[ <<label>> ] LOOP statements END LOOP [ label ]; LOOP defines an unconditional loop that is repeated indefinitely until terminated by an EXIT or RETURN statement. The optional label can be … Looping through a Cursor's ResultManual ChaptersPG18CursorsThere is a variant of the FOR statement that allows iterating through the rows returned by a cursor. The syntax is: [ <<label>> ] FOR recordvar IN bound_cursorvar [ ( [ argument_name { := | … Looping through ArraysManual ChaptersPG18Control StructuresThe FOREACH loop is much like a FOR loop, but instead of iterating through the rows returned by an SQL query, it iterates through the elements of an array value. (In general, FOREACH is mean… Looping through Query ResultsManual ChaptersPG18Control StructuresUsing a different type of FOR loop, you can iterate through the results of a query and manipulate that data accordingly. The syntax is: [ <<label>> ] FOR target IN query LOOP statements END … lostgisExtensionsExtensionsGeospatial · Extensionsspatial helper functions and types gis spatial spatiotemporal temporal tpv lostgis Geospatial lower_quantileExtensionsExtensionsFunctions and aggregates · ExtensionsLower quantile aggregate function lower_quantile Functions and aggregates lpathtreeExtensionsExtensionsData types · ExtensionsHierarchical path types using slash-separated labels hierarchy path tree lpathtree Data types lshvectorExtensionsExtensionsAI and vectors · Extensionsa feature vector type and a locality sensitive hashing index lshvector AI and vectors lsmExtensionsExtensionsForeign data wrappers · ExtensionsRocksDB foreign data wrapper for PostgreSQL fdw key-value rocksdb lsm Foreign data wrappers