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Raw Encryption FunctionsManual ChaptersPG18F.26.4. Raw Encryption Functions These functions only run a cipher over data; they don't have any advanced features of PGP encryption. Therefore they have some major problems: They use user …Raw Encryption Functions Read Committed Isolation LevelManual ChaptersPG1813.2.1. Read Committed Isolation Level Read Committed is the default isolation level in PostgreSQL. When a transaction uses this isolation level, a SELECT query (without a FOR UPDATE/SHARE c…Read Committed Isolation Level Reading Data from a Large ObjectManual ChaptersPG1833.3.6. Reading Data from a Large Object The function int lo_read(PGconn *conn, int fd, char *buf, size_t len); reads up to len bytes from large object descriptor fd into buf (which must be …Reading Data from a Large Object REASSIGN OWNEDManual ChaptersPG18REASSIGN OWNED REASSIGN OWNED — change the ownership of database objects owned by a database role Synopsis REASSIGN OWNED BY { old_role | CURRENT_ROLE | CURRENT_USER | SESSION_USER } [, ...]…REASSIGN OWNED Rebuilding Indexes ConcurrentlyManual ChaptersPG18Rebuilding Indexes Concurrently Rebuilding an index can interfere with regular operation of a database. Normally PostgreSQL locks the table whose index is rebuilt against writes and performs…Rebuilding Indexes Concurrently Recipes for Editing Data FilesManual ChaptersPG1868.2.5. Recipes for Editing Data Files Here are some suggestions about the easiest ways to perform common tasks when updating catalog data files. Add a new column with a default to a catalog…Recipes for Editing Data Files Record TypesManual ChaptersPG1841.3.5. Record Types name RECORD; Record variables are similar to row-type variables, but they have no predefined structure. They take on the actual row structure of the row they are assigne…Record Types Recovering Disk SpaceManual ChaptersPG1824.1.2. Recovering Disk Space In PostgreSQL, an UPDATE or DELETE of a row does not immediately remove the old version of the row. This approach is necessary to gain the benefits of multivers…Recovering Disk Space Recovering Using a Continuous Archive BackupManual ChaptersPG1825.3.5. Recovering Using a Continuous Archive Backup Okay, the worst has happened and you need to recover from your backup. Here is the procedure: Stop the server, if it's running. If you ha…Recovering Using a Continuous Archive Backup RecoveryManual ChaptersPG1819.5.4. Recovery This section describes the settings that apply to recovery in general, affecting crash recovery, streaming replication and archive-based replication. recovery_prefetch (enum…Recovery Recovery Control FunctionsManual ChaptersPG189.28.4. Recovery Control Functions The functions shown in Table 9.98 provide information about the current status of a standby server. These functions may be executed both during recovery an…Recovery Control Functions Recovery TargetManual ChaptersPG1819.5.6. Recovery Target By default, recovery will recover to the end of the WAL log. The following parameters can be used to specify an earlier stopping point. At most one of recovery_target…Recovery Target recovery.conf file merged into postgresql.confManual ChaptersPG18O.1. recovery.conf file merged into postgresql.conf PostgreSQL 11 and below used a configuration file named recovery.conf to manage replicas and standbys. Support for this file was removed i…recovery.conf file merged into postgresql.conf Recursive QueriesManual ChaptersPG187.8.2. Recursive Queries The optional RECURSIVE modifier changes WITH from a mere syntactic convenience into a feature that accomplishes things not otherwise possible in standard SQL. Using …Recursive Queries ReferenceManual ChaptersPG18Part VI. Reference The entries in this Reference are meant to provide in reasonable length an authoritative, complete, and formal summary about their respective subjects. More information ab…Reference Reference PagesManual ChaptersPG18J.6.1. Reference Pages Reference pages should follow a standard layout. This allows users to find the desired information more quickly, and it also encourages writers to document all relevan…Reference Pages ReferencesManual ChaptersPG18F.35.6. References GiST Development Site http://www.sai.msu.su/~megera/postgres/gist/ Tsearch2 Development Site http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/References referential_constraintsManual ChaptersPG1835.34. referential_constraints The view referential_constraints contains all referential (foreign key) constraints in the current database. Only those constraints are shown for which the cur…referential_constraints refint — Functions for Implementing Referential IntegrityManual ChaptersPG18F.41.1. refint — Functions for Implementing Referential Integrity check_primary_key() and check_foreign_key() are used to check foreign key constraints. (This functionality is long since sup…refint — Functions for Implementing Referential Integrity REFRESH MATERIALIZED VIEWManual ChaptersPG18REFRESH MATERIALIZED VIEW REFRESH MATERIALIZED VIEW — replace the contents of a materialized view Synopsis REFRESH MATERIALIZED VIEW [ CONCURRENTLY ] name [ WITH [ NO ] DATA ]REFRESH MATERIALIZED VIEW Registering Event Log on WindowsManual ChaptersPG1818.12. Registering Event Log on Windows To register a Windows event log library with the operating system, issue this command: regsvr32 pgsql_library_directory/pgevent.dll This creates regis…Registering Event Log on Windows Regression TestsManual ChaptersPG18Chapter 31. Regression Tests The regression tests are a comprehensive set of tests for the SQL implementation in PostgreSQL. They test standard SQL operations as well as the extended capabil…Regression Tests Regression TestsManual ChaptersPG18F.40.3. Regression Tests The sepgsql test suite is run if PG_TEST_EXTRA contains sepgsql (see Section 31.1.3). This method is suitable during development of PostgreSQL. Alternatively, there …Regression Tests Regular Expression DetailsManual ChaptersPG189.7.3.1. Regular Expression Details PostgreSQL's regular expressions are implemented using a software package written by Henry Spencer. Much of the description of regular expressions below i…Regular Expression Details Regular Expression EscapesManual ChaptersPG189.7.3.3. Regular Expression Escapes Escapes are special sequences beginning with \ followed by an alphanumeric character. Escapes come in several varieties: character entry, class shorthands…Regular Expression Escapes Regular Expression InterpretationManual ChaptersPG189.16.2.1.2. Regular Expression Interpretation There are minor differences in the interpretation of regular expression patterns used in like_regex filters, as described in Section 9.16.2.4.Regular Expression Interpretation Regular Expression Matching RulesManual ChaptersPG189.7.3.5. Regular Expression Matching Rules In the event that an RE could match more than one substring of a given string, the RE matches the one starting earliest in the string. If the RE co…Regular Expression Matching Rules Regular Expression MetasyntaxManual ChaptersPG189.7.3.4. Regular Expression Metasyntax In addition to the main syntax described above, there are some special forms and miscellaneous syntactic facilities available. An RE can begin with one…Regular Expression Metasyntax REINDEXManual ChaptersPG18REINDEX REINDEX — rebuild indexes Synopsis REINDEX [ ( option [, ...] ) ] { INDEX | TABLE | SCHEMA } [ CONCURRENTLY ] name REINDEX [ ( option [, ...] ) ] { DATABASE | SYSTEM } [ CONCURRENTLY…REINDEX reindexdbManual ChaptersPG18reindexdb reindexdb — reindex a PostgreSQL database Synopsis reindexdb [connection-option...] [option...] [ -S | --schema schema ] ... [ -t | --table table ] ... [ -i | --index index ] ... […reindexdb Release 18Manual ChaptersPG18E.6. Release 18 Release date: 2025-09-25Release 18 Release 18.1Manual ChaptersPG18E.5. Release 18.1 Release date: 2025-11-13 This release contains a variety of fixes from 18.0. For information about new features in major release 18, see Section E.6.Release 18.1 Release 18.2Manual ChaptersPG18E.4. Release 18.2 Release date: 2026-02-12 This release contains a variety of fixes from 18.1. For information about new features in major release 18, see Section E.6.Release 18.2 Release 18.3Manual ChaptersPG18E.3. Release 18.3 Release date: 2026-02-26 This release contains a small number of fixes from 18.2. For information about new features in major release 18, see Section E.6.Release 18.3 Release 18.4Manual ChaptersPG18E.2. Release 18.4 Release date: 2026-05-14 This release contains a variety of fixes from 18.3. For information about new features in major release 18, see Section E.6.Release 18.4 Release 18.6Manual ChaptersPG18E.1. Release 18.6 Release date: 2026-08-13 This release contains a variety of fixes from 18.4. For information about new features in major release 18, see Section E.6. Note: 18.5 was never r…Release 18.6 Release NotesManual ChaptersPG18Appendix E. Release Notes The release notes contain the significant changes in each PostgreSQL release, with major features and migration issues listed at the top. The release notes do not c…Release Notes RELEASE SAVEPOINTManual ChaptersPG18RELEASE SAVEPOINT RELEASE SAVEPOINT — release a previously defined savepoint Synopsis RELEASE [ SAVEPOINT ] savepoint_nameRELEASE SAVEPOINT ReliabilityManual ChaptersPG1828.1. Reliability Reliability is an important property of any serious database system, and PostgreSQL does everything possible to guarantee reliable operation. One aspect of reliable operati…Reliability Reliability and the Write-Ahead LogManual ChaptersPG18Chapter 28. Reliability and the Write-Ahead Log This chapter explains how to control the reliability of PostgreSQL, including details about the Write-Ahead Log.Reliability and the Write-Ahead Log