[Building Sakai] Message Center Forums looping queries

[Wagner, Michelle R.]

Hi Ashley,
Thank you for your work in tracking down this issue.  I have created https://jira.sakaiproject.org/browse/MSGCNTR-654 so we can get this fixed.

Have a great day,
Michelle
________________________________
From: sakai-dev-bounces at collab.sakaiproject.org [sakai-dev-bounces at collab.sakaiproject.org] on behalf of Ashley Willis [ashley_willis at unc.edu]
Sent: Thursday, February 02, 2012 6:09 PM
To: sakai-dev at collab.sakaiproject.org
Subject: Re: [Building Sakai] Message Center Forums looping queries

Update,
 So we have traced it to this change between 2.7.0 and 2.7.5:

DiscussionTopicBean.getAttachList()

In 2.7.5 the attachment list is built by calling forumManager which makes a db call to get attachments for each topic id.

List<Attachment> attachList = forumManager.getTopicAttachments(topic.getId());

We rolled this back to the 2.7.0 method of just getting the list from topic and the problem went away.
List<Attachment> attachList =  topic.getAttachments();

Still investigating but this seems to be the issue for us.

thanks,
Ashley Willis

Teaching and Learning Developer
University of North Carolina at Chapel Hil


On 2/2/12 4:49 PM, Ashley Willis wrote:

We are running Sakai 2.7.0 msgcntr 2.7.5. We have noticed certain forums
take several minutes to load in 2.7.5. The forum is not terribly large,
roughly 6 forums with 13 topics per forum. The instructor creates a
forum for each assignment and a topic for each student under each forum.
Students typically just upload an attachment as a response to their
topic as the assignment. What we have found is that this query is
getting called thousands of times in a loop with different surrogateKeys
which explains the long load times:

select attachment0_.ID as ID65_, attachment0_.VERSION as VERSION65_,
attachment0_.UUID as UUID65_,
attachment0_.CREATED as CREATED65_, attachment0_.CREATED_BY as
CREATED5_65_, attachment0_.MODIFIED
as MODIFIED65_, attachment0_.MODIFIED_BY as MODIFIED7_65_,
attachment0_.ATTACHMENT_ID as ATTACHMENT8_65_,
attachment0_.ATTACHMENT_URL as ATTACHMENT9_65_,
attachment0_.ATTACHMENT_NAME as ATTACHMENT10_65_,
attachment0_.ATTACHMENT_SIZE as ATTACHMENT11_65_,
attachment0_.ATTACHMENT_TYPE as ATTACHMENT12_65_,
attachment0_.m_surrogateKey as m13_65_, attachment0_.of_surrogateKey as
of14_65_, attachment0_.pf_surrogateKey
as pf15_65_, attachment0_.t_surrogateKey as t16_65_ from
MFR_ATTACHMENT_T attachment0_ where
attachment0_.t_surrogateKey=403560

On a whim, we rolled back to msgcntr to 2.7.0 and this doesn't happen,
the forum loads in a reasonable time. We don't see this query being
executed over and over.

We're about to start comparing code unless some has the magic formula.
Any takers?

thanks in advance!

ashley

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