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initdb(1)                PostgreSQL 12.5 Documentation               initdb(1)




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 23.1.

       To alter the default encoding, use the --encoding. More details can be
       found in Section 23.3.


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 23.3.1.

       -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.

       --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 23.1.

       --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.

       --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.

       -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).

       This utility, like most other PostgreSQL utilities, also uses the
       environment variables supported by libpq (see Section 33.14).


NOTES

       initdb can also be invoked via pg_ctl initdb.


SEE ALSO

       pg_ctl(1), postgres(1)



PostgreSQL 12.5                      2020                            initdb(1)

postgresql 12.5 - Generated Sun Nov 22 14:59:20 CST 2020
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