Search PostgreSQL documentation

Parallel PlansManual ChaptersPG1815.3. Parallel Plans Because each worker executes the parallel portion of the plan to completion, it is not possible to simply take an ordinary query plan and run it using multiple workers. …Parallel Plans Parallel QueryManual ChaptersPG18Chapter 15. Parallel Query PostgreSQL can devise query plans that can leverage multiple CPUs in order to answer queries faster. This feature is known as parallel query. Many queries cannot b…Parallel Query Parallel SafetyManual ChaptersPG1815.4. Parallel Safety The planner classifies operations involved in a query as either parallel safe, parallel restricted, or parallel unsafe. A parallel safe operation is one that does not c…Parallel Safety Parallel ScansManual ChaptersPG1815.3.1. Parallel Scans The following types of parallel-aware table scans are currently supported. In a parallel sequential scan, the table's blocks will be divided into ranges and shared amo…Parallel Scans Parameter Interaction via SQLManual ChaptersPG1819.1.3. Parameter Interaction via SQL PostgreSQL provides three SQL commands to establish configuration defaults. The already-mentioned ALTER SYSTEM command provides an SQL-accessible means …Parameter Interaction via SQL Parameter Interaction via the Configuration FileManual ChaptersPG1819.1.2. Parameter Interaction via the Configuration File The most fundamental way to set these parameters is to edit the file postgresql.conf, which is normally kept in the data directory. A…Parameter Interaction via the Configuration File Parameter Interaction via the ShellManual ChaptersPG1819.1.4. Parameter Interaction via the Shell In addition to setting global defaults or attaching overrides at the database or role level, you can pass settings to PostgreSQL via shell facilit…Parameter Interaction via the Shell Parameter Key WordsManual ChaptersPG1832.1.2. Parameter Key Words The currently recognized parameter key words are: host Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain commu…Parameter Key Words Parameter Names and ValuesManual ChaptersPG1819.1.1. Parameter Names and Values All parameter names are case-insensitive. Every parameter takes a value of one of five types: boolean, string, integer, floating point, or enumerated (enum…Parameter Names and Values ParametersManual ChaptersPG18F.6.1. Parameters A bloom index accepts the following parameters in its WITH clause: length Length of each signature (index entry) in bits. It is rounded up to the nearest multiple of 16. Th…Parameters ParametersManual ChaptersPG18Parameters name # A name of SQL descriptor, case sensitive. This can be an SQL identifier or a host variable.Parameters ParametersManual ChaptersPG18Parameters connection_target # connection_target specifies the target server of the connection on one of several forms. [ database_name ] [ @host ] [ :port ] # Connect over TCP/IP unix:postg…Parameters ParametersManual ChaptersPG18Parameters name # The name of the descriptor which is going to be deallocated. It is case sensitive. This can be an SQL identifier or a host variable.Parameters ParametersManual ChaptersPG18Parameters connection_name # A database connection name established by the CONNECT command. AT clause can be omitted, but such statement has no meaning. statement_name # The name of an SQL s…Parameters ParametersManual ChaptersPG18Parameters cursor_name # A cursor name, case sensitive. This can be an SQL identifier or a host variable. prepared_name # The name of a prepared query, either as an SQL identifier or a host …Parameters ParametersManual ChaptersPG18Parameters prepared_name # The name of a prepared statement. This can be an SQL identifier or a host variable. descriptor_name # A descriptor name. It is case sensitive. It can be an SQL ide…Parameters ParametersManual ChaptersPG18Parameters connection_name # A database connection name established by the CONNECT command. CURRENT # Close the “current” connection, which is either the most recently opened connection, or …Parameters ParametersManual ChaptersPG18Parameters string # A literal string or a host variable containing the SQL statement to be executed.Parameters ParametersManual ChaptersPG18Parameters descriptor_name # A descriptor name. descriptor_header_item # A token identifying which header information item to retrieve. Only COUNT, to get the number of columns in the result…Parameters ParametersManual ChaptersPG18Parameters cursor_name # The name of the cursor to be opened. This can be an SQL identifier or a host variable. value # A value to be bound to a placeholder in the cursor. This can be an SQL…Parameters ParametersManual ChaptersPG18Parameters prepared_name # An identifier for the prepared query. string # A literal string or a host variable containing a preparable SQL statement, one of SELECT, INSERT, UPDATE, or DELETE.…Parameters ParametersManual ChaptersPG18Parameters connection_name # A database connection name established by the CONNECT command. CURRENT # Set the connection to the current connection (thus, nothing happens).Parameters ParametersManual ChaptersPG18Parameters descriptor_name # A descriptor name. descriptor_header_item # A token identifying which header information item to set. Only COUNT, to set the number of descriptor items, is curre…Parameters ParametersManual ChaptersPG18Parameters type_name # The name for the new type. It must be a valid C type name. ctype # A C type specification.Parameters ParametersManual ChaptersPG18Parameters varname # A C variable name. ctype # A C type specification.Parameters ParametersManual ChaptersPG18Parameters See Section 34.8.1 for a description of the parameters.Parameters parametersManual ChaptersPG1835.33. parameters The view parameters contains information about the parameters (arguments) of all functions in the current database. Only those functions are shown that the current user has…parameters ParametersManual ChaptersPG18Parameters WORKTRANSACTION Optional key words. They have no effect. AND CHAIN If AND CHAIN is specified, a new transaction is immediately started with the same transaction characteristics (s…Parameters ParametersManual ChaptersPG18Parameters name The name (optionally schema-qualified) of an existing aggregate function. argmode The mode of an argument: IN or VARIADIC. If omitted, the default is IN. argname The name of …Parameters ParametersManual ChaptersPG18Parameters name The name (optionally schema-qualified) of an existing collation. new_name The new name of the collation. new_owner The new owner of the collation. new_schema The new schema f…Parameters ParametersManual ChaptersPG18Parameters name The name (optionally schema-qualified) of an existing conversion. new_name The new name of the conversion. new_owner The new owner of the conversion. new_schema The new schem…Parameters ParametersManual ChaptersPG18Parameters name The name of the database whose attributes are to be altered. allowconn If false then no one can connect to this database. connlimit How many concurrent connections can be mad…Parameters ParametersManual ChaptersPG18Parameters target_role Change default privileges for objects created by the target_role, or the current role if unspecified. schema_name The name of an existing schema. If specified, the def…Parameters ParametersManual ChaptersPG18Parameters name The name (possibly schema-qualified) of an existing domain to alter. domain_constraint New domain constraint for the domain. constraint_name Name of an existing constraint to…Parameters ParametersManual ChaptersPG18Parameters name The name of an existing trigger to alter. new_owner The user name of the new owner of the event trigger. new_name The new name of the event trigger. DISABLE/ENABLE [ REPLICA …Parameters ParametersManual ChaptersPG18Parameters name The name of an installed extension. new_version The desired new version of the extension. This can be written as either an identifier or a string literal. If not specified, A…Parameters ParametersManual ChaptersPG18Parameters name The name of an existing foreign-data wrapper. HANDLER handler_function Specifies a new handler function for the foreign-data wrapper. NO HANDLER This is used to specify that …Parameters ParametersManual ChaptersPG18Parameters name The name (possibly schema-qualified) of an existing foreign table to alter. If ONLY is specified before the table name, only that table is altered. If ONLY is not specified, …Parameters ParametersManual ChaptersPG18Parameters name The name (optionally schema-qualified) of an existing function. If no argument list is specified, the name must be unique in its schema. argmode The mode of an argument: IN, …Parameters ParametersManual ChaptersPG18Parameters group_name The name of the group (role) to modify. user_name Users (roles) that are to be added to or removed from the group. The users must already exist; ALTER GROUP does not cr…Parameters