NAME

       initdb - create a new PostgreSQL database cluster

SYNOPSIS

       initdb [option...] [--pgdata | -D] directory

DESCRIPTION

       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.)

       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 24.1.

       To alter the default encoding, use the --encoding. More details can be found in
       Section 24.3.

OPTIONS

       -A authmethod
       --auth=authmethod
           This option specifies the default authentication method for local users used in
           pg_hba.conf (host and local lines).  initdb will 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.

       --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 Section 24.3.1.

       -g
       --allow-group-access
           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.

       -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. If
           set, checksums are calculated for all objects, in all databases. All checksum failures
           will be reported in the pg_stat_database view. See Section 30.2 for details.

       --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 Section 24.1.

       --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
       --no-sync
           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.

       --no-instructions
           By default, initdb will write instructions for how to start the cluster at the end of
           its output. This option causes those instructions to be left out. This is primarily
           intended for use by tools that wrap initdb in platform-specific behavior, where those
           instructions are likely to be incorrect.

       --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 config
       --text-search-config=config
           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
       --waldir=directory
           This option specifies the directory where the write-ahead log should be stored.

       --wal-segsize=size
           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 WAL files.

       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.

       --discard-caches
           Run the bootstrap backend with the debug_discard_caches=1 option. This takes a very
           long time and is only of use for deep debugging.

       -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
       --no-clean
           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.

ENVIRONMENT

       PGDATA
           Specifies the directory where the database cluster is to be stored; can be overridden
           using the -D option.

       PG_COLOR
           Specifies whether to use color in diagnostic messages. Possible values are always,
           auto and never.

       TZ
           Specifies the default time zone of the created database cluster. The value should be a
           full time zone name (see Section 8.5.3).

NOTES

       initdb can also be invoked via pg_ctl initdb.

SEE ALSO

       pg_ctl(1), postgres(1)