initdb — create a new PostgreSQL™ database cluster
initdb
[option
...] [ --pgdata
| -D
] directory
initdb creates a new PostgreSQL™ database cluster. A database cluster is a collection of databases that are managed by a single server instance.
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.)
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 the section called “Locale Support”.
To alter the default encoding, use the --encoding
.
More details can be found in the section called “Character Set Support”.
-A authmethod
, --auth=authmethod
This option specifies the authentication method for local users used
in pg_hba.conf
(host
and local
lines). Do not use trust
unless you trust all local users on your system. trust
is
the default for ease of installation.
--auth-host=authmethod
This option specifies the authentication method for local users via
TCP/IP connections used in pg_hba.conf
(host
lines).
--auth-local=authmethod
This option specifies the authentication method for local users via
Unix-domain socket connections used in pg_hba.conf
(local
lines).
-D directory
, --pgdata=directory
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 variable.
-E encoding
, --encoding=encoding
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 the section called “Supported Character Sets”.
-k
, --data-checksums
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. This option can only be set during initialization, and cannot be changed later. If set, checksums are calculated for all objects, in all databases.
--locale=locale
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 the section called “Locale Support”.
--lc-collate=locale
, --lc-ctype=locale
, --lc-messages=locale
, --lc-monetary=locale
, --lc-numeric=locale
, --lc-time=locale
Like --locale
, but only sets the locale in
the specified category.
--no-locale
Equivalent to --locale=C
.
-N
, --nosync
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.
--pwfile=filename
Makes initdb read the database superuser's password from a file. The first line of the file is taken as the password.
-S
, --sync-only
Safely write all database files to disk and exit. This does not perform any of the normal initdb operations.
-T CFG
, --text-search-config=CFG
Sets the default text search configuration. See default_text_search_config for further information.
-U username
, --username=username
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 different.
-W
, --pwprompt
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.
-X directory
, --xlogdir=directory
This option specifies the directory where the transaction log should be stored.
Other, less commonly used, options are also available:
-d
, --debug
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.
-L directory
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.
-n
, --noclean
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.
Other options:
-V
, --version
Print the initdb version and exit.
-?
, --help
Show help about initdb command line arguments, and exit.
PGDATA
Specifies the directory where the database cluster is to be
stored; can be overridden using the -D
option.
TZ
Specifies the default time zone of the created database cluster. The value should be a full time zone name (see the section called “Time Zones”).
This utility, like most other PostgreSQL™ utilities, also uses the environment variables supported by libpq (see the section called “Environment Variables”).