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FETCHSQL CommandsReferenceFETCH Cursors & Prepared Statements 10 retrieve rows from a query using a cursor FETCH [ direction ] [ FROM | IN ] cursor_name where direction can be one of: NEXT PRIOR FIRST LAST ABSOLUTE …SQL Commands · Cursors & Prepared Statements fetchqExtensionsExtensionsPostgres extension that enables FetchQ capabilities fetchq FeaturesFeatures · Extensions fft_approximateExtensionsExtensionsFFT-based approximate aggregate range queries over time-series data. fft timeseries approximate aggregate fft_approximate Functions and aggregatesFunctions and aggregates · Extensions fhir_jsonbExtensionsExtensionsSynthetic FHIR JSONB data generator and query benchmark fixture for PostgreSQL. benchmark fhir jsonb synthetic-data fhir_jsonb Functions and aggregatesFunctions and aggregates · Extensions fhirbaseExtensionsExtensionsIncomplete PostgreSQL extension scaffold for a FHIR database. fhir healthcare json xml fhirbase FeaturesFeatures · Extensions fhirpathExtensionsExtensionsdata type for jsonb inspection fhirpath_pg FeaturesFeatures · Extensions fibonacciExtensionsExtensionsFibonacci extension for PostgreSQL. fibonacci Functions and aggregatesFunctions and aggregates · Extensions Field SelectionManual ChaptersPG184.2.4. Field Selection If an expression yields a value of a composite type (row type), then a specific field of the row can be extracted by writing expression.fieldname In general the row ex…Field Selection File FormatsManual ChaptersPG18File FormatsFile Formats File HeaderManual ChaptersPG18File Header The file header consists of 15 bytes of fixed fields, followed by a variable-length header extension area. The fixed fields are: Signature 11-byte sequence PGCOPY\n\377\r\n\0 — n…File Header File LocationsManual ChaptersPG1819.2. File Locations In addition to the postgresql.conf file already mentioned, PostgreSQL uses two other manually-edited configuration files, which control client authentication (their use …File Locations File System Level BackupManual ChaptersPG1825.2. File System Level Backup An alternative backup strategy is to directly copy the files that PostgreSQL uses to store the data in the database; Section 18.2 explains where these files ar…File System Level Backup File SystemsManual ChaptersPG1818.2.2. File Systems Generally, any file system with POSIX semantics can be used for PostgreSQL. Users prefer different file systems for a variety of reasons, including vendor support, perfo…File Systems File TrailerManual ChaptersPG18File Trailer The file trailer consists of a 16-bit integer word containing -1. This is easily distinguished from a tuple's field-count word. A reader should report an error if a field-count …File Trailer file_copy_methodConfigurationReferencefile_copy_method Resource Usage 18 Specifies the method used to copy files. Possible values are COPY (default) and CLONE (if operating support is available). This parameter affects: CREATE D…Configuration · Resource Usage file_extend_methodConfigurationReferencefile_extend_method Resource Usage 16 Specifies the method used to extend data files during bulk operations such as COPY. The first available option is used as the default, depending on the o…Configuration · Resource Usage file_fdwExtensionsPG18F.15. file_fdw — access data files in the server's file system The file_fdw module provides the foreign-data wrapper file_fdw, which can be used to access data files in the server's file sys…file_fdw — access data files in the server's file system file_fdw — access data files in the server's file systemManual ChaptersPG18F.15. file_fdw — access data files in the server's file system The file_fdw module provides the foreign-data wrapper file_fdw, which can be used to access data files in the server's file sys…file_fdw — access data files in the server's file system file_fdw_programExtensionsExtensionsBackport of file_fdw PROGRAM support, exposing a file_fdw-like foreign data wrapper that reads from external commands. backport fdw file program file_fdw_program Foreign data wrappersForeign data wrappers · Extensions file_fixed_length_fdwExtensionsExtensionsForeign data wrapper for files with fixed-length fields. fdw file fixed-length file_fixed_length_fdw Foreign data wrappersForeign data wrappers · Extensions file_textarray_fdwExtensionsExtensionsForeign data wrapper returning each text-file row as a text array. csv fdw file text-array file_textarray_fdw Foreign data wrappersForeign data wrappers · Extensions filenode_map_inspectExtensionsExtensionsCheck and examine pg_filenode.map files filenode_map_inspect AdministrationAdministration · Extensions FilesManual ChaptersPG18Files postmaster.pid pg_ctl examines this file in the data directory to determine whether the server is currently running. postmaster.opts If this file exists in the data directory, pg_ctl (…Files FilesManual ChaptersPG18Files psqlrc and ~/.psqlrc # Unless it is passed an -X option, psql attempts to read and execute commands from the system-wide startup file (psqlrc) and then the user's personal startup file…Files filesystemExtensionsExtensionsfilesystem foreign data wrapper events plpgsql postgresql rest-api semantics system-catalog version-control-system widgets filesystem Foreign data wrappersForeign data wrappers · Extensions fillfactorCommand-line ToolsPG18fillfactor (integer) The fillfactor for a table is a percentage between 10 and 100. 100 (complete packing) is the default. When a smaller fillfactor is specified, INSERT operations pack tabl…CREATE TABLE › Parameters › Storage Parameters financialExtensionsExtensionsFinancial aggregate functions pg_financial Functions and aggregatesFunctions and aggregates · Extensions find_bucket_tsExtensionsExtensionsArtifacts of BaCon. For VLDB26 reviewers only. find_bucket_ts Time seriesTime series · Extensions fioExtensionsExtensionsPostgreSQL File I/O Functions pg_fio AdministrationAdministration · Extensions firebird_fdwExtensionsExtensionsForeign data wrapper for Firebird firebird_fdw Foreign data wrappersForeign data wrappers · Extensions fireflyExtensionsExtensionsPostGIS-backed Firefly database schema for tracking 3D points and add/delete operations by task. firefly geometry point3d postgis firefly_database GeospatialGeospatial · Extensions first_lastExtensionsExtensionsAggregate functions to return first or last "n" elements in a group aggregate first last first_last Functions and aggregatesFunctions and aggregates · Extensions first_last_aggExtensionsExtensionsfirst() and last() aggregate functions first_last_agg Functions and aggregatesFunctions and aggregates · Extensions first_valueFunctionsReferencefirst_value Window Functions 10 returns value evaluated at the row that is the first row of the window frame first_value ( value any ) → same type as value returns value evaluated at the row…Functions · Window Functions fixeddecimalExtensionsExtensionsFixed-precision decimal type optimized for performance and storage. data-type fixed-decimal numeric fixeddecimal Data typesData types · Extensions flameExtensionsExtensionsPGRX proof-of-concept extension that generates text embeddings with fastembed/MiniLM. embedding pgrx rag flame AI and vectorsAI and vectors · Extensions flateExtensionsExtensionsRaw DEFLATE compression and decompression functions for bytea bytea compression deflate zlib pgflate UtilitiesUtilities · Extensions floatfileExtensionsExtensionsSimple file storage for arrays of floats floatfile UtilitiesUtilities · Extensions Floating-Point DifferencesManual ChaptersPG1831.2.4. Floating-Point Differences Some of the tests involve computing 64-bit floating-point numbers (double precision) from table columns. Differences in results involving mathematical func…Floating-Point Differences Floating-Point TypesManual ChaptersPG188.1.3. Floating-Point Types The data types real and double precision are inexact, variable-precision numeric types. On all currently supported platforms, these types are implementations of I…Floating-Point Types