pg_database
The catalog pg_database stores information about the available databases. Databases are created with the CREATE DATABASE command. Consult Chapter 22 for details about the meaning of some of the parameters. Unlike most system catalogs, pg_database is shared across all databases of a cluster: there is only one copy of pg_database per cluster, not one per database.
English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.
Reading PG 18·Select a recorded version
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- oid, datname, datdba, encoding, datlocprovider, datistemplate, datallowconn, dathasloginevt, datconnlimit, datfrozenxid, datminmxid, dattablespace, datcollate, datctype, datlocale, daticurules, datcollversion, datacl
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Definition PG 18
The catalog pg_database stores information about the available databases. Databases are created with the CREATE DATABASE command. Consult Chapter 22 for details about the meaning of some of the parameters. Unlike most system catalogs, pg_database is shared across all databases of a cluster: there is only one copy of pg_database per cluster, not one per database.
Catalog columns
| Column | Type | Nullability | Description |
|---|---|---|---|
| oid | oid | Not null | Row identifier |
| datname | name | Not null | Database name |
| datdba | oid | Not null | Owner of the database, usually the user who created it |
| encoding | int4 | Not null | Character encoding for this database (pg_encoding_to_char() can translate this number to the encoding name) |
| datlocprovider | char | Not null | Locale provider for this database: b = builtin, c = libc, i = icu |
| datistemplate | bool | Not null | If true, then this database can be cloned by any user with CREATEDB privileges; if false, then only superusers or the owner of the database can clone it. |
| datallowconn | bool | Not null | If false then no one can connect to this database. This is used to protect the template0 database from being altered. |
| dathasloginevt | bool | Not null | Indicates that there are login event triggers defined for this database. This flag is used to avoid extra lookups on the pg_event_trigger table during each backend startup. This flag is used internally by PostgreSQL and should not be manually altered or read for monitoring purposes. |
| datconnlimit | int4 | Not null | Sets maximum number of concurrent connections that can be made to this database. -1 means no limit, -2 indicates the database is invalid. |
| datfrozenxid | xid | Not null | All transaction IDs before this one have been replaced with a permanent (“frozen”) transaction ID in this database. This is used to track whether the database needs to be vacuumed in order to prevent transaction ID wraparound or to allow pg_xact to be shrunk. It is the minimum of the per-table pg_class.relfrozenxid values. |
| datminmxid | xid | Not null | All multixact IDs before this one have been replaced with a transaction ID in this database. This is used to track whether the database needs to be vacuumed in order to prevent multixact ID wraparound or to allow pg_multixact to be shrunk. It is the minimum of the per-table pg_class.relminmxid values. |
| dattablespace | oid | Not null | The default tablespace for the database. Within this database, all tables for which pg_class.reltablespace is zero will be stored in this tablespace; in particular, all the non-shared system catalogs will be there. |
| datcollate | text | Not null | LC_COLLATE for this database |
| datctype | text | Not null | LC_CTYPE for this database |
| datlocale | text | Nullable | Collation provider locale name for this database. If the provider is libc, datlocale is NULL; datcollate and datctype are used instead. |
| daticurules | text | Nullable | ICU collation rules for this database |
| datcollversion | text | Nullable | Provider-specific version of the collation. This is recorded when the database is created and then checked when it is used, to detect changes in the collation definition that could lead to data corruption. |
| datacl | aclitem[] | Nullable | Access privileges; see Section 5.8 for details |
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Definition sources
center · PostgreSQL 18 · catalog-bilingual-repair:7241f24015c53415002c210f2e5c881061e75e09b7d72fc323da41aa393c6ed5
Text language: en · catalog-bilingual-repair:7241f24015c53415002c210f2e5c881061e75e09b7d72fc323da41aa393c6ed5