initdb(1) PostgreSQL 15.8 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 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 23.3 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, takes the locale
settings from the environment, and determines the encoding from the
locale settings. This is almost always sufficient, unless there are
special requirements.
To choose a different locale for the cluster, use the option --locale.
There are also individual options --lc-* (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, the ICU library can be used to provide locale services.
(Again, this only sets the default for subsequently created databases.)
To select this option, specify --locale-provider=icu. 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 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). See Section 21.1
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 database 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 default is derived from the locale, if the
libc locale provider is used, or UTF8 if the ICU locale provider is
used. 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.
--icu-locale=locale
Specifies the ICU locale ID, if the ICU locale provider is used.
-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.
--locale-provider={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.
-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. Generally, this option
is useful for ensuring reliable recovery after changing fsync from
off to on.
-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), Section 21.1
PostgreSQL 15.8 2024 initdb(1)
postgresql 15.8 - Generated Tue Aug 20 15:03:23 CDT 2024