52.15. 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.

   Table 52.15. pg_database Columns

   Column Type

   Description

   oid oid

   Row identifier

   datname name

   Database name

   datdba oid (references pg_authid.oid)

   Owner of the database, usually the user who created it

   encoding int4

   Character encoding for this database (pg_encoding_to_char() can
   translate this number to the encoding name)

   datlocprovider char

   Locale provider for this database: b = builtin, c = libc, i = icu

   datistemplate bool

   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

   If false then no one can connect to this database. This is used to
   protect the template0 database from being altered.

   dathasloginevt bool

   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

   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

   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

   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 (references pg_tablespace.oid)

   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

   LC_COLLATE for this database

   datctype text

   LC_CTYPE for this database

   datlocale text

   Collation provider locale name for this database. If the provider is
   libc, datlocale is NULL; datcollate and datctype are used instead.

   daticurules text

   ICU collation rules for this database

   datcollversion text

   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[]

   Access privileges; see Section 5.8 for details