From: Chuck Remes <cremes.devlist@...>
Date: 2009-09-10T06:59:01+09:00
Subject: Re: EventMachine.defer and ActiveRecord connection pool?


On Sep 9, 2009, at 4:43 PM, Artūras Šlajus wrote:

> Chuck Remes wrote:
>> On Sep 9, 2009, at 4:14 PM, Artūras Šlajus wrote:
>>
>>> Nop, it's 1 second for testing. It happens even if you set it to 1
>>> minute. Loads of time to clean up and still...
>>>
>>
>> Hmm, that is curious. Then here's another guess...
>>
>> I haven't used rails in a long time, but I recall that AR required a
>> call to verify_connections! or something crazy when running with
>> threads.
> Tried this with no luck :) Thou it gave me some idea for googling...
>
>> This is because each call opens its own connection to the
>> database but there is (or was) no automatic close. So it could be  
>> that
>> your threaded calls are opening up db connections and never closing
>> them. You need to figure out how to close the connection or get AR to
>> figure out that the others are stale or should be garbage collected.
>
> It seems that ActiveRecord::Base.clear_reloadable_connections! in:
>
>          EventMachine.defer(
>            proc do
>              SingletonBlock.started(name)
>              LOGGER.block(name) { operation.call }
>            end,
>            proc do
>              LOGGER.block("#{name} CALLBACK") { callback.call } if
> callback
>              SingletonBlock.finished(name)
>              ActiveRecord::Base.clear_reloadable_connections!
>            end
>          )
>
> actually helped :)
> (http://coderrr.wordpress.com/2009/01/12/rails-22-activerecord-connection-cleanup/ 
> )
>
> Thanks for ideas and help! ;)

You are welcome. This made me curious so I looked a little deeper and  
found a better choice for you.

Look up #release_connection in  
ActiveRecord::ConnectionAdapters::ConnectionPool. It does exactly what  
you need whereas that call to #clear_reloadable_connections! might be  
doing unnecessary work.

Good luck.

cr