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POSIX Time Zone SpecificationsManual ChaptersPG18B.5. POSIX Time Zone Specifications PostgreSQL can accept time zone specifications that are written according to the POSIX standard's rules for the TZ environment variable. POSIX time zone s…POSIX Time Zone Specifications Post-Installation SetupManual ChaptersPG1817.5. Post-Installation SetupPost-Installation Setup postgresManual ChaptersPG18postgres postgres — PostgreSQL database server Synopsis postgres [option...]postgres Postgres95Manual ChaptersPG182.2. Postgres95 In 1994, Andrew Yu and Jolly Chen added an SQL language interpreter to POSTGRES. Under a new name, Postgres95 was subsequently released to the web to find its own way in the …Postgres95 postgres_fdw — access data stored in external PostgreSQL serversManual ChaptersPG18F.38. postgres_fdw — access data stored in external PostgreSQL servers The postgres_fdw module provides the foreign-data wrapper postgres_fdw, which can be used to access data stored in exte…postgres_fdw — access data stored in external PostgreSQL servers PostgreSQLManual ChaptersPG182.3. PostgreSQL By 1996, it became clear that the name “Postgres95” would not stand the test of time. We chose a new name, PostgreSQL, to reflect the relationship between the original POSTGR…PostgreSQL PostgreSQL Client ApplicationsManual ChaptersPG18PostgreSQL Client Applications This part contains reference information for PostgreSQL client applications and utilities. Not all of these commands are of general utility; some might require…PostgreSQL Client Applications PostgreSQL Coding ConventionsManual ChaptersPG18Chapter 55. PostgreSQL Coding ConventionsPostgreSQL Coding Conventions PostgreSQL Error CodesManual ChaptersPG18Appendix A. PostgreSQL Error Codes All messages emitted by the PostgreSQL server are assigned five-character error codes that follow the SQL standard's conventions for “SQLSTATE” codes. Appl…PostgreSQL Error Codes PostgreSQL FeaturesManual ChaptersPG1817.3.3.2. PostgreSQL Features The options described in this section enable building of various PostgreSQL features that are not built by default. Most of these are non-default only because t…PostgreSQL Features PostgreSQL FeaturesManual ChaptersPG1817.4.3.2. PostgreSQL Features The options described in this section enable building of various optional PostgreSQL features. Most of these require additional software, as described in Sectio…PostgreSQL Features PostgreSQL LimitsManual ChaptersPG18Appendix K. PostgreSQL Limits Table K.1 describes various hard limits of PostgreSQL. However, practical limits, such as performance limitations or available disk space may apply before absol…PostgreSQL Limits PostgreSQL Server ApplicationsManual ChaptersPG18PostgreSQL Server Applications This part contains reference information for PostgreSQL server applications and support utilities. These commands can only be run usefully on the host where th…PostgreSQL Server Applications PrecisionManual ChaptersPG18F.10.2. Precision Values are stored internally as 64-bit floating point numbers. This means that numbers with more than about 16 significant digits will be truncated.Precision PrecisionManual ChaptersPG18F.39.3. Precision seg values are stored internally as pairs of 32-bit floating point numbers. This means that numbers with more than 7 significant digits will be truncated. Numbers with 7 or…Precision Predefined CollationsManual ChaptersPG1823.2.2.2. Predefined Collations If the operating system provides support for using multiple locales within a single program (newlocale and related functions), or if support for ICU is config…Predefined Collations Predefined RolesManual ChaptersPG1821.5. Predefined Roles PostgreSQL provides a set of predefined roles that provide access to certain, commonly needed, privileged capabilities and information. Administrators (including roles…Predefined Roles PrefaceManual ChaptersPG18Preface This book is the official documentation of PostgreSQL. It has been written by the PostgreSQL developers and other volunteers in parallel to the development of the PostgreSQL software…Preface Preferred Index Types for Text SearchManual ChaptersPG1812.9. Preferred Index Types for Text Search There are two kinds of indexes that can be used to speed up full text searches: GIN and GiST. Note that indexes are not mandatory for full text se…Preferred Index Types for Text Search PREPAREManual ChaptersPG18PREPARE PREPARE — prepare a statement for execution Synopsis PREPARE prepared_name FROM stringPREPARE PREPAREManual ChaptersPG18PREPARE PREPARE — prepare a statement for execution Synopsis PREPARE name [ ( data_type [, ...] ) ] AS statementPREPARE Prepare Filter CallbackManual ChaptersPG1847.6.4.9. Prepare Filter Callback The optional filter_prepare_cb callback is called to determine whether data that is part of the current two-phase commit transaction should be considered fo…Prepare Filter Callback Prepare for Publisher UpgradesManual ChaptersPG1829.13.1. Prepare for Publisher Upgrades pg_upgrade attempts to migrate logical slots. This helps avoid the need for manually defining the same logical slots on the new publisher. Migration o…Prepare for Publisher Upgrades Prepare for Subscriber UpgradesManual ChaptersPG1829.13.2. Prepare for Subscriber Upgrades Setup the subscriber configurations in the new subscriber. pg_upgrade attempts to migrate subscription dependencies which includes the subscription's…Prepare for Subscriber Upgrades PREPARE TRANSACTIONManual ChaptersPG18PREPARE TRANSACTION PREPARE TRANSACTION — prepare the current transaction for two-phase commit Synopsis PREPARE TRANSACTION transaction_idPREPARE TRANSACTION Prepared StatementsManual ChaptersPG1834.3.4. Prepared Statements When the values to be passed to an SQL statement are not known at compile time, or the same statement is going to be used many times, then prepared statements can…Prepared Statements Preparing the Primary for Standby ServersManual ChaptersPG1826.2.3. Preparing the Primary for Standby Servers Set up continuous archiving on the primary to an archive directory accessible from the standby, as described in Section 25.3. The archive lo…Preparing the Primary for Standby Servers Preprocessor DirectivesManual ChaptersPG1834.9. Preprocessor Directives Several preprocessor directives are available that modify how the ecpg preprocessor parses and processes a file.Preprocessor Directives PrerequisitesManual ChaptersPG18Prerequisites There are some prerequisites for pg_createsubscriber to convert the target server into a logical replica. If these are not met, an error will be reported. The source and target…Prerequisites Preset OptionsManual ChaptersPG1819.15. Preset Options The following “parameters” are read-only. As such, they have been excluded from the sample postgresql.conf file. These options report various aspects of PostgreSQL beha…Preset Options Preventing Server SpoofingManual ChaptersPG1818.7. Preventing Server Spoofing While the server is running, it is not possible for a malicious user to take the place of the normal database server. However, when the server is down, it is…Preventing Server Spoofing Preventing Transaction ID Wraparound FailuresManual ChaptersPG1824.1.5. Preventing Transaction ID Wraparound Failures PostgreSQL's MVCC transaction semantics depend on being able to compare transaction ID (XID) numbers: a row version with an insertion XI…Preventing Transaction ID Wraparound Failures Previous PostgreSQL VersionsManual ChaptersPG1819.13.1. Previous PostgreSQL Versions array_nulls (boolean) # This controls whether the array input parser recognizes unquoted NULL as specifying a null array element. By default, this is on…Previous PostgreSQL Versions Primary KeysManual ChaptersPG185.5.4. Primary Keys A primary key constraint indicates that a column, or group of columns, can be used as a unique identifier for rows in the table. This requires that the values be both uni…Primary Keys Primary ServerManual ChaptersPG1819.6.2. Primary Server These parameters can be set on the primary server that is to send replication data to one or more standby servers. Note that in addition to these parameters, wal_level…Primary Server Prior ReleasesManual ChaptersPG18E.7. Prior Releases Release notes for prior release branches can be found at https://www.postgresql.org/docs/release/Prior Releases PrivilegesManual ChaptersPG185.8. Privileges When an object is created, it is assigned an owner. The owner is normally the role that executed the creation statement. For most kinds of objects, the initial state is that …Privileges PrivilegesManual ChaptersPG18E.6.3.1.5. Privileges Add function pg_get_acl() to retrieve database access control details (Joel Jacobson) § § Add function has_largeobject_privilege() to check large object privileges (Yug…Privileges ProblemsManual ChaptersPG1823.1.6. Problems If locale support doesn't work according to the explanation above, check that the locale support in your operating system is correctly configured. To check what locales are …Problems Procedural Language FunctionsManual ChaptersPG1836.8. Procedural Language Functions PostgreSQL allows user-defined functions to be written in other languages besides SQL and C. These other languages are generically called procedural langu…Procedural Language Functions