Too Many Connections

[Trivedi, Apaar]

This may not even be a Django problem, but I saw this on two of my dev sites today, both running the same code base, our version of django is from the trunk, and maybe a week or so old.  One site was running the light weight server, the other site was running apache/mod_python.  Both are connected to the same database.  Here is the error:

 

Traceback (most recent call last):

  File "/usr/local/python2.5/lib/python2.5/site-packages/mod_python/importer.py", line 1537, in HandlerDispatch\n    default=default_handler, arg=req, silent=hlist.silent)

  File "/usr/local/python2.5/lib/python2.5/site-packages/mod_python/importer.py", line 1229, in _process_target\n    result = _execute_target(config, req, object, arg)

  File "/usr/local/python2.5/lib/python2.5/site-packages/mod_python/importer.py", line 1128, in _execute_target\n    result = object(arg)

  File "/usr/local/python2.5/lib/python2.5/site-packages/django/core/handlers/modpython.py", line 222, in handler\n    return ModPythonHandler()(req)

  File "/usr/local/python2.5/lib/python2.5/site-packages/django/core/handlers/modpython.py", line 199, in __call__\n    response = middleware_method(request, response)

  File "/usr/local/lib/python2.5/site-packages/django/contrib/sessions/middleware.py", line 33, in process_response

  File "/usr/local/lib/python2.5/site-packages/django/contrib/sessions/backends/db.py", line 52, in save

  File "/usr/local/lib/python2.5/site-packages/django/contrib/sessions/backends/base.py", line 152, in _get_session_key

  File "/usr/local/lib/python2.5/site-packages/django/contrib/sessions/backends/base.py", line 144, in _get_new_session_key

  File "/usr/local/lib/python2.5/site-packages/django/contrib/sessions/backends/db.py", line 25, in exists

  File "/usr/local/lib/python2.5/site-packages/django/db/models/manager.py", line 93, in get

  File "/usr/local/lib/python2.5/site-packages/django/db/models/query.py", line 298, in get

  File "/usr/local/lib/python2.5/site-packages/django/db/models/query.py", line 154, in __len__

  File "/usr/local/lib/python2.5/site-packages/django/db/models/query.py", line 269, in iterator

  File "/usr/local/lib/python2.5/site-packages/django/db/models/sql/query.py", line 206, in results_iter

  File "/usr/local/lib/python2.5/site-packages/django/db/models/sql/query.py", line 1699, in execute_sql

  File "/usr/local/lib/python2.5/site-packages/django/db/backends/__init__.py", line 56, in cursor

  File "/usr/local/lib/python2.5/site-packages/django/db/backends/mysql/base.py", line 262, in _cursor

  File "/usr/local/python2.5/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/__init__.py", line 74, in Connect

  File "/usr/local/python2.5/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/connections.py", line 170, in __init__\n    super(Connection, self).__init__(*args, **kwargs2)

OperationalError: (1040, 'Too many connections')

 

Obviously it’s django going through mysqldb, and connection problem is in mysqldb, but I was wondering if anyone on this list can shed some light on this.  I did a bit of googling and noticed other people using django were having similar problems.  Does anyone know what causes this and how I can fix it?  These sites are both internal dev sites, therefore not anywhere close to high traffic. 

Thank you

Apaar

 

[DULMANDAKH Sukhbaatar]

> File
> "/usr/local/python2.5/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/__init__.py",
> line 74, in Connect
>
> File
> "/usr/local/python2.5/lib/python2.5/site-packages/MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/connections.py",
> line 170, in __init__\n super(Connection, self).__init__(*args,
> **kwargs2)
>
> OperationalError: (1040, 'Too many connections')

as you can see above, it's mysql problem. mysql server have some
default limitation on concurrent connections. you can increase
max_connections in my.cnf. depending on your linux distro my.cnf may
be located in different places. for me, or on ubuntu it's at
/etc/mysql/my.cnf, and you need to uncomment the line, and increase
the value.

by default mysql gets 100 concurrent connections. and the question is
why is dev site is getting that much connection?

--
Regards
Dulmandakh

[Eric Abrahamsen]

On Dec 10, 2008, at 1:30 AM, DULMANDAKH Sukhbaatar wrote:

>
>> File
>> "/usr/local/python2.5/lib/python2.5/site-packages/

>> MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/__init__.py",
>> line 74, in Connect
>>
>> File
>> "/usr/local/python2.5/lib/python2.5/site-packages/
>> MySQL_python-1.2.2-py2.5-linux-i686.egg/MySQLdb/connections.py",
>> line 170, in __init__\n super(Connection, self).__init__(*args,
>> **kwargs2)
>>
>> OperationalError: (1040, 'Too many connections')

It's probably worth using django-logging or one of the other 3rd party
packages to check how many queries your views are executing. The only
time I ever saw this error was with high load on an extremely
inefficient view (something like 60 queries in one view), and tweaking
your use of the ORM can reduce those problems significantly.

Eric