Fixed #20215 -- Disabled persistent connections by default.

        conn.setdefault('ENGINE', 'django.db.backends.dummy')

        if conn['ENGINE'] == 'django.db.backends.' or not conn['ENGINE']:

            conn['ENGINE'] = 'django.db.backends.dummy'

        conn.setdefault('CONN_MAX_AGE', 600)

        conn.setdefault('CONN_MAX_AGE', 0)

        conn.setdefault('OPTIONS', {})

        conn.setdefault('TIME_ZONE', 'UTC' if settings.USE_TZ else settings.TIME_ZONE)

        for setting in ['NAME', 'USER', 'PASSWORD', 'HOST', 'PORT']:

Setting :setting:`DEBUG = False <DEBUG>` disables several features that are

only useful in development. In addition, you can tune the following settings.

:setting:`CONN_MAX_AGE`

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

Enabling `persistent database connections <persistent-database-connections>`_

can result in a nice speed-up when connecting to the database accounts for a

significant part of the request processing time.

This helps a lot on virtualized hosts with limited network performance.

:setting:`TEMPLATE_LOADERS`

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

.. versionadded:: 1.6

Persistent connections avoid the overhead of re-establishing a connection to

the database in each request. By default, connections are kept open for up 10

minutes — if not specified, :setting:`CONN_MAX_AGE` defaults to 600 seconds.

the database in each request. They're controlled by the

:setting:`CONN_MAX_AGE` parameter which defines the maximum lifetime of a

connection. It can be set independently for each database.

Django 1.5 and earlier didn't have persistent connections. To restore the

legacy behavior of closing the connection at the end of every request, set

:setting:`CONN_MAX_AGE` to ``0``.

For unlimited persistent connections, set :setting:`CONN_MAX_AGE` to ``None``.

The default value is ``0``, preserving the historical behavior of closing the

database connection at the end of each request. To enable persistent

connections, set :setting:`CONN_MAX_AGE` to a positive number of seconds. For

unlimited persistent connections, set it to ``None``.

Connection management

~~~~~~~~~~~~~~~~~~~~~

Sometimes a database won't be accessed by the majority of your views, for

example because it's the database of an external system, or thanks to caching.

In such cases, you should set :setting:`CONN_MAX_AGE` to a lower value, or

even ``0``, because it doesn't make sense to maintain a connection that's

unlikely to be reused. This will help keep the number of simultaneous

connections to this database small.

In such cases, you should set :setting:`CONN_MAX_AGE` to a low value or even

``0``, because it doesn't make sense to maintain a connection that's unlikely

to be reused. This will help keep the number of simultaneous connections to

this database small.

The development server creates a new thread for each request it handles,

negating the effect of persistent connections.

negating the effect of persistent connections. Don't enable them during

development.

When Django establishes a connection to the database, it sets up appropriate

parameters, depending on the backend being used. If you enable persistent

connections, this setup is no longer repeated every request. If you modify

parameters such as the connection's isolation level or time zone, you should

either restore Django's defaults at the end of each request, force an

appropriate value at the beginning of each request, or disable persistent

connections.

.. _postgresql-notes:

.. versionadded:: 1.6

Default: ``600``

Default: ``0``

The lifetime of a database connection, in seconds. Use ``0`` to close database

connections at the end of each request — Django's historical behavior — and

Django now supports reusing the same database connection for several requests.

This avoids the overhead of re-establishing a connection at the beginning of

each request.

By default, database connections will kept open for 10 minutes. This behavior

is controlled by the :setting:`CONN_MAX_AGE` setting. To restore the previous

behavior of closing the connection at the end of each request, set

:setting:`CONN_MAX_AGE` to ``0``. See :ref:`persistent-database-connections`

for details.

each request. For backwards compatibility, this feature is disabled by

default. See :ref:`persistent-database-connections` for details.

Time zone aware aggregation

~~~~~~~~~~~~~~~~~~~~~~~~~~~

``hour``, ``minute``, or ``second``, the new lookups will clash with you field

names. Append an explicit :lookup:`exact` lookup if this is an issue.

Persistent database connections

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Connection setup not repeated for each request

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When Django establishes a connection to the database, it sets up appropriate

parameters, depending on the backend being used. Since `persistent database

connections <persistent-database-connections>`_ are enabled by default in

Django 1.6, this setup isn't repeated at every request any more. If you

modifiy parameters such as the connection's isolation level or time zone, you

should either restore Django's defaults at the end of each request, force an

appropriate value at the beginning of each request, or disable persistent

connections.

``BooleanField`` no longer defaults to ``False``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~