[gradebook2-dev] MySQL transactions

[Thomas Amsler]

Actually, we have our own Hibernate layer to write to the gradebook
tables. Here are the key files:

https://source.sakaiproject.org/contrib///gradebook2/trunk/war/WEB-INF/db.xml
https://source.sakaiproject.org/contrib///gradebook2/trunk/server/src/java/org/sakaiproject/gradebook/gwt/sakai/hibernate/GradebookToolServiceImpl.java

Right now, we are not using "in app" transactions that would span
client requests.

Best,
-- Thomas


On Thu, Feb 2, 2012 at 8:02 PM, John Bush <john.bush at rsmart.com> wrote:
> I believe all the db access in gb2 runs.through the edu-services project. Id
> check to make sure that the spring config is configuring the transactions
> correctly. I haven't been in there in awhile but I remember somethings with
> the  gradebook svc were done a little uniquely.
>
> Not sent with my iphone.
>
> On Feb 2, 2012 3:08 PM, "Kusnetz, Jeremy" <JKusnetz at apus.edu> wrote:
>>
>> We are working on a project to scale up our MySQL instance by
>> incorporating some read/write splitting to a master MySQL node and multiple
>> slave nodes.  The main theory is writes should go the master and reads
>> should go to the slaves (which are replicating from the master).  If writes
>> and reads are all incorporated within a transaction, then all the writes AND
>> reads from that transaction should all go to the master.  This prevents
>> problems dealing with replication latency.
>>
>>
>>
>> Everything seems to be working well in Sakai, except for Gradebook2.
>>
>>
>>
>> I haven’t looked at the code yet, but the way it’s acting is if certain
>> groups of queries aren’t within transactions.
>>
>>
>>
>> So for example if you remove an item, all the remaining items within the
>> category should automatically update their weights.  But when we have r/w
>> splitting enabled, this doesn’t happen all of the time.  Sometimes the item
>> will go away, but the remaining items won’t update their weights.  Again
>> without looking it looks like the update of the item to set it as deleted is
>> not in a transaction with updating the remaining item’s weight values.  If
>> all of these were in a transaction then all the updates and selects would
>> hit the master node which would obviously be in sync with itself.
>>
>>
>>
>> Any thoughts?
>>
>>
>>
>> Jeremy Kusnetz | Sr. Systems Engineer
>>
>>
>>
>> American Public University System
>> American Military University  |  American Public University
>> 661 S George Street, Charles Town, WV 25414
>> T 304-885-5333 | M 703-967-5212 |  jkusnetz at apus.edu| www.apus.edu
>>
>>
>>
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