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initdb
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initdb

initdb — create a newPostgreSQL database cluster

Synopsis

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

Description

initdb creates a newPostgreSQLdatabase cluster.

Creating a database cluster consists of creating thedirectories in which the cluster data will live, generating the shared catalog tables (tables that belong to the whole cluster rather than to any particular database), and creating thepostgres,template1, andtemplate0 databases. Thepostgres database is a default database meant for use by users, utilities and third party applications.template1 andtemplate0 are meant as source databases to be copied by laterCREATE DATABASE commands.template0 should never be modified, but you can add objects totemplate1, which by default will be copied into databases created later. SeeSection 22.3 for more details.

Althoughinitdb 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 usechown to assign ownership of that directory to the database user account, thensu to become the database user to runinitdb.

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 thatinitdb creates. Since the server cannot be run as root, you must not runinitdb as root either. (It will in fact refuse to do so.)

For security reasons the new cluster created byinitdb 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. These can also be set separately for each database when it is created.initdb determines those settings for the template databases, which will serve as the default for all other databases.

By default,initdb uses the locale providerlibc (seeSection 23.1.4). Thelibc locale provider takes the locale settings from the environment, and determines the encoding from the locale settings.

To choose a different locale for the cluster, use the option--locale. There are also individual options--lc-* and--icu-locale (see below) to set values for the individual locale categories. Note that inconsistent settings for different locale categories can give nonsensical results, so this should be used with care.

Alternatively,initdb can use the ICU library to provide locale services by specifying--locale-provider=icu. The server must be built with ICU support. To choose the specific ICU locale ID to apply, use the option--icu-locale. Note that for implementation reasons and to support legacy code,initdb will still select and initialize libc locale settings when the ICU locale provider is used.

Wheninitdb runs, it will print out the locale settings it has chosen. If you have complex requirements or specified multiple options, it is advisable to check that the result matches what was intended.

More details about locale settings can be found inSection 23.1.

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

Options

-Aauthmethod --auth=authmethod#

This option specifies the default authentication method for local users used inpg_hba.conf (host andlocal lines). SeeSection 20.1 for an overview of valid values.

initdb will prepopulatepg_hba.conf entries using the specified authentication method for non-replication as well as replication connections.

Do not usetrust 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 inpg_hba.conf (host lines).

--auth-local=authmethod#

This option specifies the authentication method for local users via Unix-domain socket connections used inpg_hba.conf (local lines).

-Ddirectory --pgdata=directory#

This option specifies the directory where the database cluster should be stored. This is the only information required byinitdb, but you can avoid writing it by setting thePGDATA environment variable, which can be convenient since the database server (postgres) can find the data directory later by the same variable.

-Eencoding --encoding=encoding#

Selects the encoding of the template databases. This will also be the default encoding of any database you create later, unless you override it then. The character sets supported by thePostgreSQL server are described inSection 23.3.1.

By default, the template database encoding is derived from the locale. If--no-locale is specified (or equivalently, if the locale isC orPOSIX), then the default isUTF8 for the ICU provider andSQL_ASCII for thelibc provider.

-g --allow-group-access#

Allows users in the same group as the cluster owner to read all cluster files created byinitdb. This option is ignored onWindows as it does not supportPOSIX-style group permissions.

--icu-locale=locale#

Specifies the ICU locale when the ICU provider is used. Locale support is described inSection 23.1.

--icu-rules=rules#

Specifies additional collation rules to customize the behavior of the default collation. This is supported for ICU only.

-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 thepg_stat_database view. SeeSection 28.2 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 thatinitdb runs in. Locale support is described inSection 23.1.

If--locale-provider isbuiltin,--locale or--builtin-locale must be specified and set toC orC.UTF-8.

--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.

--builtin-locale=locale#

Specifies the locale name when the builtin provider is used. Locale support is described inSection 23.1.

--locale-provider={builtin|libc|icu}#

This option sets the locale provider for databases created in the new cluster. It can be overridden in theCREATE DATABASE command when new databases are subsequently created. The default islibc (seeSection 23.1.4).

--pwfile=filename#

Makesinitdb read the bootstrap superuser's password from a file. The first line of the file is taken as the password.

-Tconfig --text-search-config=config#

Sets the default text search configuration. Seedefault_text_search_config for further information.

-Uusername --username=username#

Sets the user name of thebootstrap superuser. This defaults to the name of the operating-system user runninginitdb.

-W --pwprompt#

Makesinitdb prompt for a password to give the bootstrap 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.

-Xdirectory --waldir=directory#

This option specifies the directory where the write-ahead log should be stored.

--wal-segsize=size#

Set theWAL 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:

-cname=value --setname=value#

Forcibly set the server parametername tovalue duringinitdb, and also install that setting in the generatedpostgresql.conf file, so that it will apply during future server runs. This option can be given more than once to set several parameters. It is primarily useful when the environment is such that the server will not start at all using the default parameters.

-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 programinitdb uses to create the catalog tables. This option generates a tremendous amount of extremely boring output.

--discard-caches#

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

-Ldirectory#

Specifies whereinitdb 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, wheninitdb 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.

-N --no-sync#

By default,initdb will wait for all files to be written safely to disk. This option causesinitdb 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 wrapinitdb in platform-specific behavior, where those instructions are likely to be incorrect.

-s --show#

Show internal settings and exit, without doing anything else. This can be used to debug theinitdb installation.

--sync-method=method#

When set tofsync, which is the default,initdb will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

On Linux,syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. Seerecovery_init_sync_method for information about the caveats to be aware of when usingsyncfs.

This option has no effect when--no-sync is used.

-S --sync-only#

Safely write all database files to disk and exit. This does not perform any of the normalinitdb operations. Generally, this option is useful for ensuring reliable recovery after changingfsync fromoff toon.

Other options:

-V --version#: Print theinitdb version and exit.
-? --help#: Show help aboutinitdb 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 arealways,auto andnever.
TZ#: Specifies the default time zone of the created database cluster. The value should be a full time zone name (seeSection 8.5.3).

Notes

initdb can also be invoked viapg_ctl initdb.