initdb - create a new PostgreSQL database cluster
initdb [option...] [--pgdata |
initdb creates a new PostgreSQL database cluster. A
database cluster is a collection of databases that are managed by a single
Creating a database cluster consists of creating the directories
in which the database data will live, generating the shared catalog tables
(tables that belong to the whole cluster rather than to any particular
database), and creating the template1 and postgres databases. When you later
create a new database, everything in the template1 database is copied.
(Therefore, anything installed in template1 is automatically copied into
each database created later.) The postgres database is a default database
meant for use by users, utilities and third party applications.
Although initdb will attempt to create the specified data
directory, it might not have permission if the parent directory of the
desired data directory is root-owned. To initialize in such a setup, create
an empty data directory as root, then use chown to assign ownership
of that directory to the database user account, then su to become the
database user to run initdb.
initdb must be run as the user that will own the server
process, because the server needs to have access to the files and
directories that initdb creates. Since the server cannot be run as
root, you must not run initdb as root either. (It will in fact refuse
to do so.)
For security reasons the new cluster created by initdb will
only be accessible by the cluster owner by default. The
--allow-group-access option allows any user in the same group as the
cluster owner to read files in the cluster. This is useful for performing
backups as a non-privileged user.
initdb initializes the database cluster's default locale
and character set encoding. The character set encoding, collation order
(LC_COLLATE) and character set classes (LC_CTYPE, e.g., upper, lower, digit)
can be set separately for a database when it is created. initdb
determines those settings for the template1 database, which will serve as
the default for all other databases.
To alter the default collation order or character set classes, use
the --lc-collate and --lc-ctype options. Collation orders
other than C or POSIX also have a performance penalty. For these reasons it
is important to choose the right locale when running initdb.
The remaining locale categories can be changed later when the
server is started. You can also use --locale to set the default for
all locale categories, including collation order and character set classes.
All server locale values (lc_*) can be displayed via SHOW ALL. More
details can be found in Section 23.1.
To alter the default encoding, use the --encoding. More
details can be found in Section 23.3.
This option specifies the default authentication method
for local users used in pg_hba.conf (host and local lines). initdb
prepopulate pg_hba.conf entries using the specified authentication method for
non-replication as well as replication connections.
Do not use trust unless you trust all local users on your system.
trust is the default for ease of installation.
This option specifies the authentication method for local
users via TCP/IP connections used in pg_hba.conf (host lines).
This option specifies the authentication method for local
users via Unix-domain socket connections used in pg_hba.conf (local
This option specifies the directory where the database
cluster should be stored. This is the only information required by
initdb, but you can avoid writing it by setting the PGDATA
environment variable, which can be convenient since the database server
(postgres) can find the database directory later by the same
Selects the encoding of the template database. This will
also be the default encoding of any database you create later, unless you
override it there. The default is derived from the locale, or SQL_ASCII if
that does not work. The character sets supported by the PostgreSQL server are
described in Section 23.3.1.
Allows users in the same group as the cluster owner to
read all cluster files created by initdb. This option is ignored on
Windows as it does not support POSIX-style group permissions.
Use checksums on data pages to help detect corruption by
the I/O system that would otherwise be silent. Enabling checksums may incur a
noticeable performance penalty. If set, checksums are calculated for all
objects, in all databases. All checksum failures will be reported in the
Sets the default locale for the database cluster. If this
option is not specified, the locale is inherited from the environment that
initdb runs in. Locale support is described in
Like --locale, but only sets the locale in the
Equivalent to --locale=C.
By default, initdb will wait for all files to be
written safely to disk. This option causes initdb to return without
waiting, which is faster, but means that a subsequent operating system crash
can leave the data directory corrupt. Generally, this option is useful for
testing, but should not be used when creating a production installation.
Makes initdb read the database superuser's
password from a file. The first line of the file is taken as the
Safely write all database files to disk and exit. This
does not perform any of the normal initdb operations.
Sets the default text search configuration. See
default_text_search_config for further information.
Selects the user name of the database superuser. This
defaults to the name of the effective user running initdb. It is really
not important what the superuser's name is, but one might choose to keep the
customary name postgres, even if the operating system user's name is
Makes initdb prompt for a password to give the
database superuser. If you don't plan on using password authentication, this
is not important. Otherwise you won't be able to use password authentication
until you have a password set up.
This option specifies the directory where the write-ahead
log should be stored.
Set the WAL segment size, in megabytes. This is the size
of each individual file in the WAL log. The default size is 16 megabytes. The
value must be a power of 2 between 1 and 1024 (megabytes). This option can
only be set during initialization, and cannot be changed later.
It may be useful to adjust this size to control the granularity of
WAL log shipping or archiving. Also, in databases with a high volume of WAL,
the sheer number of WAL files per directory can become a performance and
management problem. Increasing the WAL file size will reduce the number of
Other, less commonly used, options are also available:
Print debugging output from the bootstrap backend and a
few other messages of lesser interest for the general public. The bootstrap
backend is the program initdb uses to create the catalog tables. This
option generates a tremendous amount of extremely boring output.
Specifies where initdb should find its input files
to initialize the database cluster. This is normally not necessary. You will
be told if you need to specify their location explicitly.
By default, when initdb determines that an error
prevented it from completely creating the database cluster, it removes any
files it might have created before discovering that it cannot finish the job.
This option inhibits tidying-up and is thus useful for debugging.
Print the initdb version and exit.
Show help about initdb command line arguments, and
Specifies the directory where the database cluster is to
be stored; can be overridden using the -D option.
Specifies whether to use color in diagnostic messages.
Possible values are always, auto and never.
Specifies the default time zone of the created database
cluster. The value should be a full time zone name (see
This utility, like most other PostgreSQL utilities, also uses the
environment variables supported by libpq (see Section 33.14).
initdb can also be invoked via pg_ctl initdb.