pg_database#

The pg_database system catalog table stores information about the available databases. Databases are created with the CREATE DATABASE SQL command. Unlike most system catalogs, pg_database is shared across all databases in the system. There is only one copy of pg_database per system, not one per database.

Table 1. pg_catalog.pg_database

column

type

references

description

datname

name

Database name.

datdba

oid

pg_authid.oid

Owner of the database, usually the user who created it.

encoding

integer

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

datistemplate

boolean

If true then this database can be used in the TEMPLATE clause of CREATE DATABASE to create a new database as a clone of this one.

datallowconn

boolean

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

datconnlimit

integer

Sets the maximum number of concurrent connections that can be made to this database. -1 means no limit.

datlastsysoid

oid

Last system OID in the database.

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_clog to be shrunk. It is the minimum of the per-table pg_class_internal.relfrozenxid values.

dattablespace

oid

pg_tablespace.oid

The default tablespace for the database. Within this database, all tables for which pg_class_internal.reltablespace is zero will be stored in this tablespace. All non-shared system catalogs will also be there.

dat2tablespace

oid

The OID of tablespace this database belongs to.

datconfig

text[]

Session defaults for user-settable server configuration parameters.

datacl

aclitem[]

Database access privileges as given by GRANT and REVOKE.