Commands

********

This chapter discusses the usage of the available console scripts.

postgresql.bin.pg_python

========================

The ``pg_python`` command provides a simple way to write Python scripts against a

single target database. It acts like the regular Python console command, but

takes standard PostgreSQL options as well to specify the client parameters

to make establish connection with. The Python environment is then augmented

with the following built-ins:

``db``

The PG-API connection object.

``xact``

``db.xact``, the transaction creator.

``settings``

``db.settings``

``prepare``

``db.prepare``, the statement creator.

``proc``

``db.proc``

``do``

``db.do``, execute a single DO statement.

``sqlexec``

``db.execute``, execute multiple SQL statements (``None`` is always returned)

pg_python Usage

---------------

Usage: postgresql.bin.pg_python [connection options] [script] ...

Options:

--unix=UNIX path to filesystem socket

--ssl-mode=SSLMODE SSL requirement for connectivity: require, prefer,

allow, disable

-s SETTINGS, --setting=SETTINGS

run-time parameters to set upon connecting

-I PQ_IRI, --iri=PQ_IRI

database locator string

[pq://user:password@host:port/database?setting=value]

-h HOST, --host=HOST database server host

-p PORT, --port=PORT database server port

-U USER, --username=USER

user name to connect as

-W, --password prompt for password

-d DATABASE, --database=DATABASE

database's name

--pq-trace=PQ_TRACE trace PQ protocol transmissions

-C PYTHON_CONTEXT, --context=PYTHON_CONTEXT

Python context code to run[file://,module:,<code>]

-m PYTHON_MAIN Python module to run as script(__main__)

-c PYTHON_MAIN Python expression to run(__main__)

--version show program's version number and exit

--help show this help message and exit

Interactive Console Backslash Commands

--------------------------------------

Inspired by ``psql``::

>>> \?

Backslash Commands:

\? Show this help message.

\E Edit a file or a temporary script.

\e Edit and Execute the file directly in the context.

\i Execute a Python script within the interpreter's context.

\set Configure environment variables. \set without arguments to show all

\x Execute the Python command within this process.

pg_python Examples

------------------

Module execution taking advantage of the new built-ins::

$ python3 -m postgresql.bin.pg_python -h localhost -W -m timeit "prepare('SELECT 1').first()"

Password for pg_python[pq://jwp@localhost:5432]:

1000 loops, best of 3: 1.35 msec per loop

$ python3 -m postgresql.bin.pg_python -h localhost -W -m timeit -s "ps=prepare('SELECT 1')" "ps.first()"

Password for pg_python[pq://jwp@localhost:5432]:

1000 loops, best of 3: 442 usec per loop

Simple interactive usage::

$ python3 -m postgresql.bin.pg_python -h localhost -W

Password for pg_python[pq://jwp@localhost:5432]:

>>> ps = prepare('select 1')

>>> ps.first()

1

>>> c = ps()

>>> c.read()

[(1,)]

>>> ps.close()

>>> import sys

>>> sys.exit(0)

postgresql.bin.pg_dotconf

=========================

pg_dotconf is used to modify a PostgreSQL cluster's configuration file.

It provides a means to apply settings specified from the command line and from a

file referenced using the ``-f`` option.

.. warning::

``include`` directives in configuration files are *completely* ignored. If

modification of an included file is desired, the command must be applied to

that specific file.

pg_dotconf Usage

----------------

Usage: postgresql.bin.pg_dotconf [--stdout] [-f filepath] postgresql.conf ([param=val]|[param])*

Options:

--version show program's version number and exit

-h, --help show this help message and exit

-f SETTINGS, --file=SETTINGS

A file of settings to *apply* to the given

"postgresql.conf"

--stdout Redirect the product to standard output instead of

writing back to the "postgresql.conf" file

Examples

--------

Modifying a simple configuration file::

$ echo "setting = value" >pg.conf

# change 'setting'

$ python3 -m postgresql.bin.pg_dotconf pg.conf setting=newvalue

$ cat pg.conf

setting = 'newvalue'

# new settings are appended to the file

$ python3 -m postgresql.bin.pg_dotconf pg.conf another_setting=value

$ cat pg.conf

setting = 'newvalue'

another_setting = 'value'

# comment a setting

$ python3 -m postgresql.bin.pg_dotconf pg.conf another_setting

$ cat pg.conf

setting = 'newvalue'

#another_setting = 'value'

When a setting is given on the command line, it must been seen as one argument

to the command, so it's *very* important to avoid invocations like::

$ python3 -m postgresql.bin.pg_dotconf pg.conf setting = value

ERROR: invalid setting, '=' after 'setting'

HINT: Settings must take the form 'setting=value' or 'setting_name_to_comment'. Settings must also be received as a single argument.