Ubuntu Manpage: initdb - create a new PostgreSQL database cluster

NAME

       initdb - create a new PostgreSQL database cluster

SYNOPSIS

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

DESCRIPTION

initdb creates a new PostgreSQL database cluster.

Creating a database cluster consists of creating the directories 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 the postgres, template1, and
template0 databases. The postgres database is a default database meant for use by users,
utilities and third party applications. template1 and template0 are meant as source
databases to be copied by later CREATE DATABASE commands. template0 should never be
modified, but you can add objects to template1, which by default will be copied into
databases created later. See Section 22.3 for more details.

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. 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 provider libc (see Section 23.1.4). The libc 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.

When initdb 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 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). See Section 20.1 for an overview of valid values.

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 data directory later by the same variable.

-E encoding
--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 the PostgreSQL server are described in Section 23.3.1.

By default, the template database encoding is derived from the locale. If --no-locale
is specified (or equivalently, if the locale is C or POSIX), then the default is UTF8
for the ICU provider and SQL_ASCII for the libc provider.

-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.

--icu-locale=locale
Specifies the ICU locale when the ICU provider is used. Locale support is described in
Section 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 the pg_stat_database view. See Section 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 that initdb runs in. Locale support is
described in Section 23.1.

If --locale-provider is builtin, --locale or --builtin-locale must be specified and
set to C or C.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 in Section 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 the CREATE DATABASE command when new databases are subsequently
created. The default is libc (see Section 23.1.4).

--pwfile=filename
Makes initdb read the bootstrap superuser's password from a file. The first line of
the file is taken as the password.

-T config
--text-search-config=config
Sets the default text search configuration. See default_text_search_config for further
information.

-U username
--username=username
Sets the user name of the bootstrap superuser. This defaults to the name of the
operating-system user running initdb.

-W
--pwprompt
Makes initdb 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.

-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:

-c name=value
--set name=value
Forcibly set the server parameter name to value during initdb, and also install that
setting in the generated postgresql.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 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.

-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.

-s
--show
Show internal settings and exit, without doing anything else. This can be used to
debug the initdb installation.

--sync-method=method
When set to fsync, 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. See recovery_init_sync_method for information about the caveats to be
aware of when using syncfs.

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
normal initdb operations. Generally, this option is useful for ensuring reliable
recovery after changing fsync from off to on.

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