I turned off the ERXJDBCConenctionBroker and set the
er.extensions.ERXObjectStoreCoordinatorPool.maxCoordinators = 10. When I run
my application under a load test I don't see any additional db connections
being made. I can see some of these messages in my logs:
INFO er.extensions.eof.ERXObjectStoreCoordinatorPool - setting
ERXEC.factory to MultiOSCFactory
INFO er.extensions.eof.ERXObjectStoreCoordinatorPool - initializing Pool...
INFO er.extensions.eof.ERXObjectStoreCoordinatorPool - initializing Pool
finished
So I assume that I should see multiple db connections at some point. My load
test starts a new thread for each virtual user. Even with lazy loading I
would have expected to see at least 10 DB connections once I reached 15
virtual users.
Am I missing a config param somewhere?
Thanks in advance
Dov Rosenberg
On 8/27/10 1:11 AM, "Mike Schrag" <mschrag@pobox.com> wrote:
> It's not wrong, I suppose, if you're doing direct custom access to the
> database. In that case, you would actually benefit from multiple database
> channels. But you're not going to benefit from EOF :)
>
> ms
>
> On Aug 26, 2010, at 11:55 PM, Chuck Hill wrote:
>
>> I remember those docs. I think they are just wrong.
>>
>> Chuck
>>
>>
>> On Aug 26, 2010, at 10:21 PM, Dov Rosenberg wrote:
>>
>>> Looking thru some old EOF documentation (v5.2) I found -
>>> http://developer.apple.com/legacy/mac/library/documentation/WebObjects/Enter
>>> prise_Objects/EnterpriseObjects.pdf
>>>
>>> The second step in instrumenting multithreading in an Enterprise Objects
>>> application is determining what
>>> kind of concurrency you need. This requires knowing (or predicting) the
>>> bottlenecks within your application.
>>> Do bottlenecks occur at the database level when multiple users attempt
>>> concurrent access to the data source
>>> so that adding more database channels alleviates the bottleneck? Do
>>> bottlenecks occur elsewhere in the
>>> access layer so that providing a separate access layer for each user
>>> alleviates the bottleneck?
>>> The answers to these questions help determine the mechanism you need to use
>>> to instrument concurrency
>>> within an Enterprise Objects application. Two common design patterns for
>>> concurrency within Enterprise
>>> Objects applications are to:
>>> ¡½ Provide each user with an independent access layer stack.
>>> ¡½ Provide multiple database channels on demand.
>>>
>>> The doc goes onto say that using multiple OSC introduces additional
>>> challenges with concurrency between OSC¡¦s.
>>>
>>> The doc even gives code samples on providing multiple OSC and adding
>>> additional database channels when a DatabaseChannelNeededNotification is
>>> received
>>>
>>> I am interested to hear your analysis of the Wonder code. I will keep
>>> experimenting
>>>
>>> Dov
>>>
>>> On 8/26/10 9:58 PM, "Mike Schrag" <mschrag@pobox.com> wrote:
>>>
>>>> I can't vouch for connectionbroker's accuracy of impl, but I would expect
>>>> all
>>>> your db access to be behind a single lock and therefore not benefit from
>>>> multiple channels. Of course most of the people who might challenge my
>>>> claims
>>>> are probably drunk in Montreal right now. I'll check source later tonight
>>>> and
>>>> see if I'm talking crazy.
>>>>
>>>> Sent from my iPhone
>>>>
>>>> On Aug 26, 2010, at 9:55 PM, Dov Rosenberg <DRosenberg@Inquira.Com> wrote:
>>>>
>>>>> Is it not a good idea to use the ERXJDBCAdaptor and ConnectionBroker
>>>>> together?
>>>>>
>>>>> I would have thought if I only used a single OSC it would have made sure
>>>>> that each transaction went to the correct connection.
>>>>>
>>>>> Should there only be a single db connection for each OSC?
>>>>>
>>>>> Thanks
>>>>>
>>>>> Dov Rosenberg
>>>>>
>>>>>
>>>>> On 8/26/10 9:46 PM, "Mike Schrag" <mschrag@pobox.com> wrote:
>>>>>
>>>>>> With one osc you saw activity on multiple connections concurrently? I
>>>>>> can't
>>>>>> imagine that scenario has a happy ending. I don't even know how I would
>>>>>> be
>>>>>> possible given that all your db access should be behind a dbc lock. You
>>>>>> might
>>>>>> see use of multiple connections, but that would probably explain your
>>>>>> failing
>>>>>> commits (inserting on conn 1, committing conn 2, maybe). Each osc should
>>>>>> end
>>>>>> up having its own conn and you should see parallel access that way.
>>>>>>
>>>>>> To answer more I think I need to not be on an iPhone :)
>>>>>>
>>>>>> Sent from my iPhone
>>>>>>
>>>>>> On Aug 26, 2010, at 9:37 PM, Dov Rosenberg <DRosenberg@Inquira.Com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hmmm - I did a little jmeter test and definitely saw an improvement in
>>>>>>> page
>>>>>>> view performance and saw activity on multiple DB connections during the
>>>>>>> test. By simply adding the connection broker with a single OSC.
>>>>>>>
>>>>>>> If I set up object store pooling wont that increase issues with
>>>>>>> concurrency
>>>>>>> within my app? I.e. Trying to update data that has already been updated
>>>>>>> in >>>> a
>>>>>>> different OSC?
>>>>>>>
>>>>>>> I am using the Jgroups synchronizer between instances already.
>>>>>>>
>>>>>>> Would the following set of properties be consistent with each other:
>>>>>>>
>>>>>>> er.extensions.ERXObjectStoreCoordinatorPool.maxCoordinators = 10
>>>>>>> er.extensions.ERXJDBCAdaptor.className=er.extensions.jdbc.ERXJDBCAdaptor
>>>>>>> er.extensions.ERXJDBCAdaptor.useConnectionBroker = true
>>>>>>> er.extensions.remoteSynchronizer.enabled=true
>>>>>>> er.extensions.remoteSynchronizer=er.jgroups.ERJGroupsSynchronizer
>>>>>>> dbMinConnectionsGLOBAL=10
>>>>>>> dbMaxConnectionsGLOBAL=15
>>>>>>> er.extensions.ERXJDBCConnectionBroker.maxConnections=15
>>>>>>> er.extensions.ERXJDBCConnectionBroker.minConnections=10
>>>>>>>
>>>>>>> If I understand what is going on I should get 10 EOF stacks sharing a
>>>>>>> pool
>>>>>>> of 15 database connections. I assume there is some magic running behind
>>>>>>> the
>>>>>>> scenes to keep all of the OSC in sync with each other?
>>>>>>>
>>>>>>> Thanks again
>>>>>>>
>>>>>>> Dov Rosenberg
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 8/26/10 9:00 PM, "Mike Schrag" <mschrag@pobox.com> wrote:
>>>>>>>
>>>>>>>> Connection pooling won't really do anything for you because each stack
>>>>>>>> is
>>>>>>>> single threaded. You want object store coordinator pooling.
>>>>>>>>
>>>>>>>> Sent from my iPhone
>>>>>>>>
>>>>>>>> On Aug 26, 2010, at 8:45 PM, Dov Rosenberg <DRosenberg@Inquira.Com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> During some testing today I turned on support for connection pooling
>>>>>>>>> in
>>>>>>>>> my
>>>>>>>>> application using the ERXJDBCAdaptor and the ERXJDBCConnectionBroker.
>>>>>>>>> I
>>>>>>>>> could
>>>>>>>>> see the connections being used fine and all of the things that did
>>>>>>>>> fetches
>>>>>>>>> seemed to work without any issues. However when I tried doing
>>>>>>>>> something
>>>>>>>>> that
>>>>>>>>> generated an INSERT the transactions did not commit and no changes
>>>>>>>>> were
>>>>>>>>> made.
>>>>>>>>> I could see the SQL being generated as expected and the saveChanges()
>>>>>>>>> happened without throwing any exception ¡V just no data got written to
>>>>>>>>> the
>>>>>>>>> database. As soon as I disabled the use of the connection pool
>>>>>>>>> everything
>>>>>>>>> worked properly again.
>>>>>>>>>
>>>>>>>>> Any thoughts would be appreciated
>>>>>>>>>
>>>>>>>>> Dov Rosenberg
>>>>>>>>> _______________________________________________
>>>>>>>>> Do not post admin requests to the list. They will be ignored.
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>>>>>>>>> Help/Unsubscribe/Update your Subscription:
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>>>>>>>>> com
>>>>>>>>>
>>>>>>>>> This email sent to mschrag@pobox.com
>>>>>>>
>>>>>
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>>
>> --
>> Chuck Hill Senior Consultant / VP Development
>>
>> Practical WebObjects - for developers who want to increase their overall
>> knowledge of WebObjects or who are trying to solve specific problems.
>> http://www.global-village.net/products/practical_webobjects
>>
>>
>>
>>
>>
>>
>>
>
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