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`psycopg2.pool` -- Connections pooling
======================================

.. sectionauthor:: Daniele Varrazzo <daniele.varrazzo@gmail.com>

.. index::
    pair: Connection; Pooling

.. module:: psycopg2.pool

Creating new PostgreSQL connections can be an expensive operation.  This
module offers a few pure Python classes implementing simple connection pooling
directly in the client application.

.. class:: AbstractConnectionPool(minconn, maxconn, \*args, \*\*kwargs)

Base class implementing generic key-based pooling code.

New *minconn* connections are created automatically. The pool will support
    a maximum of about *maxconn* connections.  *\*args* and *\*\*kwargs* are
    passed to the `~psycopg2.connect()` function.

The following methods are expected to be implemented by subclasses:

.. method:: getconn(key=None)

Get a free connection from the pool.

The *key* parameter is optional: if used, the connection will be
        associated to the key and calling `!getconn()` with the same key again
        will return the same connection.

.. method:: putconn(conn, key=None, close=False)

Put away a connection.

If *close* is `!True`, discard the connection from the pool.
        *key* should be used consistently with `getconn()`.

.. method:: closeall

Close all the connections handled by the pool.

Note that all the connections are closed, including ones
        eventually in use by the application.

The following classes are `AbstractConnectionPool` subclasses ready to
be used.

.. autoclass:: SimpleConnectionPool

.. note:: This pool class is useful only for single-threaded applications.

.. index:: Multithread; Connection pooling

.. autoclass:: ThreadedConnectionPool

.. note:: This pool class can be safely used in multi-threaded applications.

[-] extras.rst [edit]
[-] advanced.rst [edit]
[-] install.rst [edit]
[-] errorcodes.rst [edit]
[-] tz.rst [edit]
[-] Makefile [edit]
[-] extensions.rst [edit]
[-] faq.rst [edit]
[-] errors.rst [edit]
[-] module.rst [edit]
[-] license.rst [edit]
[+] tools
[-] index.rst [edit]
[-] cursor.rst [edit]
[-] sql.rst [edit]
[-] conf.py [edit]
[+] _static
[-] news.rst [edit]
[-] usage.rst [edit]
[+] ..
[-] connection.rst [edit]
[-] pool.rst [edit]