51.15. 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 51.15.
pg_database
Columns
| Name | Type | References | Description |
|---|---|---|---|
oid
|
oid
|
Row identifier | |
datname
|
name
|
Database name | |
datdba
|
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)
|
|
datcollate
|
name
|
LC_COLLATE for this database | |
datctype
|
name
|
LC_CTYPE for this database | |
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.
|
|
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. | |
datlastsysoid
|
oid
|
Last system OID in the database; useful particularly to pg_dump | |
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
|
|
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.
|
datacl
|
aclitem[]
|
Access privileges; see Section 5.7 for details |