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default_statistics_targetConfigurationReferencedefault_statistics_target Query Tuning 10 Sets the default statistics target for table columns without a column-specific target set via ALTER TABLE SET STATISTICS. Larger values increase the…Configuration · Query Tuning default_table_access_methodConfigurationReferencedefault_table_access_method Client Connection Defaults 12 This parameter specifies the default table access method to use when creating tables or materialized views if the CREATE command doe…Configuration · Client Connection Defaults default_tablespaceConfigurationReferencedefault_tablespace Client Connection Defaults 10 This variable specifies the default tablespace in which to create objects (tables and indexes) when a CREATE command does not explicitly spec…Configuration · Client Connection Defaults default_text_search_configConfigurationReferencedefault_text_search_config Client Connection Defaults 10 Selects the text search configuration that is used by those variants of the text search functions that do not have an explicit argume…Configuration · Client Connection Defaults default_toast_compressionConfigurationReferencedefault_toast_compression Client Connection Defaults 14 This variable sets the default TOAST compression method for values of compressible columns. (This can be overridden for individual col…Configuration · Client Connection Defaults default_transaction_deferrableConfigurationReferencedefault_transaction_deferrable Client Connection Defaults 10 When running at the serializable isolation level, a deferrable read-only SQL transaction may be delayed before it is allowed to p…Configuration · Client Connection Defaults default_transaction_isolationConfigurationReferencedefault_transaction_isolation Client Connection Defaults 10 Each SQL transaction has an isolation level, which can be either “read uncommitted”, “read committed”, “repeatable read”, or “seri…Configuration · Client Connection Defaults default_transaction_read_onlyConfigurationReferencedefault_transaction_read_only Client Connection Defaults 10 A read-only SQL transaction cannot alter non-temporary tables. This parameter controls the default read-only status of each new tr…Configuration · Client Connection Defaults default_with_oidsConfigurationReferencedefault_with_oids Version and Platform Compatibility 10 This controls whether CREATE TABLE and CREATE TABLE AS include an OID column in newly-created tables, if neither WITH OIDS nor WITHOUT…Configuration · Version and Platform Compatibility DefaultsManual ChaptersPG18F.10.4. Defaults This union: select cube_union('(0,5,2),(2,3,1)', '0'); cube_union ------------------- (0, 0, 0),(2, 5, 2) (1 row) does not contradict common sense, neither does the intersec…Defaults definedFunctionsPG18defined ( hstore, text ) → boolean Does hstore contain a non-NULL value for key? defined('a=>NULL', 'a') → fhstore — hstore key/value datatype › hstore Operators and Functions Defining New ProbesManual ChaptersPG1827.5.4. Defining New Probes New probes can be defined within the code wherever the developer desires, though this will require a recompilation. Below are the steps for inserting new probes: …Defining New Probes Defining New Range TypesManual ChaptersPG188.17.8. Defining New Range Types Users can define their own range types. The most common reason to do this is to use ranges over subtypes not provided among the built-in range types. For exa…Defining New Range Types DefinitionsManual ChaptersPG18F.22.1. Definitions A label is a sequence of alphanumeric characters, underscores, and hyphens. Valid alphanumeric character ranges are dependent on the database locale. For example, in C lo…Definitions degreesFunctionsReferencedegrees Mathematical Functions And Operators 10 radians to degrees degrees ( dp ) → dp radians to degrees 11 12 13 Converts radians to degrees degrees ( double precision ) → double precision…Functions · Mathematical Functions And Operators Delaying ExecutionManual ChaptersPG189.9.6. Delaying Execution The following functions are available to delay execution of the server process: pg_sleep ( double precision ) pg_sleep_for ( interval ) pg_sleep_until ( timestamp w…Delaying Execution deleteFunctionsPG18delete ( hstore, text ) → hstore Deletes pair with matching key. delete('a=>1,b=>2', 'b') → "a"=>"1"hstore — hstore key/value datatype › hstore Operators and Functions DELETEManual ChaptersPG18DELETE DELETE — delete rows of a table Synopsis [ WITH [ RECURSIVE ] with_query [, ...] ] DELETE FROM [ ONLY ] table_name [ * ] [ [ AS ] alias ] [ USING from_item [, ...] ] [ WHERE condition…DELETE DELETESQL CommandsReferenceDELETE Queries & Data 10 delete rows of a table [ WITH [ RECURSIVE ] with_query [, ...] ] DELETE FROM [ ONLY ] table_name [ * ] [ [ AS ] alias ] [ USING from_item [, ...] ] [ WHERE condition…SQL Commands · Queries & Data Deleting DataManual ChaptersPG186.3. Deleting Data So far we have explained how to add data to tables and how to change data. What remains is to discuss how to remove data that is no longer needed. Just as adding data is o…Deleting Data DeletionsManual ChaptersPG182.9. Deletions Rows can be removed from a table using the DELETE command. Suppose you are no longer interested in the weather of Hayward. Then you can do the following to delete those rows f…Deletions demopgextensionExtensionsExtensionsSample Postgres Extension - pg_cmake cmake extension pgxs postgresql demopgextension FeaturesFeatures · Extensions dense_rankFunctionsReferencedense_rank Aggregate Functions 10 rank of the hypothetical row, without gaps dense_rank ( args ) WITHIN GROUP (ORDER BY sorted_args) → bigint rank of the hypothetical row, without gaps dense…Functions · Aggregate Functions Dependency TrackingManual ChaptersPG185.15. Dependency Tracking When you create complex database structures involving many tables with foreign key constraints, views, triggers, functions, etc. you implicitly create a net of depe…Dependency Tracking Deprecation NoticeManual ChaptersPG18F.50.1. Deprecation Notice From PostgreSQL 8.3 on, there is XML-related functionality based on the SQL/XML standard in the core server. That functionality covers XML syntax checking and XPat…Deprecation Notice DESCRIBEManual ChaptersPG18DESCRIBE DESCRIBE — obtain information about a prepared statement or result set Synopsis DESCRIBE [ OUTPUT ] prepared_name USING [ SQL ] DESCRIPTOR descriptor_name DESCRIBE [ OUTPUT ] prepar…DESCRIBE describe_resultsetExtensionsExtensionsPostgreSQL extension to show names, data types, and attributes of columns in an arbitrary result set postgresql postgresql-extension describe_resultset UtilitiesUtilities · Extensions DescriptionManual ChaptersPG18Description clusterdb is a utility for reclustering tables in a PostgreSQL database. It finds tables that have previously been clustered, and clusters them again on the same index that was l…Description DescriptionManual ChaptersPG18Description createdb creates a new PostgreSQL database. Normally, the database user who executes this command becomes the owner of the new database. However, a different owner can be specifi…Description DescriptionManual ChaptersPG18Description createuser creates a new PostgreSQL user (or more precisely, a role). Only superusers and users with CREATEROLE privilege can create new users, so createuser must be invoked by s…Description DescriptionManual ChaptersPG18Description dropdb destroys an existing PostgreSQL database. The user who executes this command must be a database superuser or the owner of the database. dropdb is a wrapper around the SQL …Description DescriptionManual ChaptersPG18Description dropuser removes an existing PostgreSQL user. Superusers can use this command to remove any role; otherwise, only non-superuser roles can be removed, and only by a user who posse…Description DescriptionManual ChaptersPG18Description ecpg is the embedded SQL preprocessor for C programs. It converts C programs with embedded SQL statements to normal C code by replacing the SQL invocations with special function …Description DescriptionManual ChaptersPG18Description initdb creates a new PostgreSQL database cluster. Creating a database cluster consists of creating the directories in which the cluster data will live, generating the shared cata…Description DescriptionManual ChaptersPG18Description pg_ctl is a utility for initializing a PostgreSQL database cluster, starting, stopping, or restarting the PostgreSQL database server (postgres), or displaying the status of a run…Description DescriptionManual ChaptersPG18Description pg_dumpall is a utility for writing out (“dumping”) all PostgreSQL databases of a cluster into one script file. The script file contains SQL commands that can be used as input to…Description DescriptionManual ChaptersPG18Description pg_isready is a utility for checking the connection status of a PostgreSQL database server. The exit status specifies the result of the connection check.Description DescriptionManual ChaptersPG18Description pg_amcheck supports running amcheck's corruption checking functions against one or more databases, with options to select which schemas, tables and indexes to check, which kinds …Description DescriptionManual ChaptersPG18Description pg_basebackup is used to take a base backup of a running PostgreSQL database cluster. The backup is taken without affecting other clients of the database, and can be used both fo…Description DescriptionManual ChaptersPG18Description pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the e…Description