[samigo-team] Performance testing and Samigo 2.9

Tue May 8 15:02:59 PDT 2012

Hi Stephen,

This is the feature to allow instructors to attach files in Comments field.
You can go to either Question Score page or Student Score page. In the
"Comments for Student" column, you can use the "Add Attachment" button to
attach files. And students can download the files when they review their
assessments.

I think we can switch this to lazy load and add the logic to certain flows
when the comments are needed. For example, view Question Score
(instructor), view Student Score (instructor), and review submitted
assessments (student).

Thanks,
Karen

On Tue, May 8, 2012 at 4:59 AM, Stephen Marquard <stephen.marquard at uct.ac.za
> wrote:

> Hi all,
>
> We have identified one of the performance issues as related to queries
> for SAM_GRADINGATTACHMENT_T. In fact these aren't queries as such, but
> cases where Hibernate issues a Prepare statement for a query but without
> an Execute (for mysql server-side prepared statements), presumably
> because it decides it has the object and doesn't need or some other
> Hibernate behaviour.
>
> If we switch on mysql logging, we see just over 90,000 Prepare
> statements like this:
>
> Prepare   select itemgradin0_.ITEMGRADINGID as ITEMGRA15_1_,
> itemgradin0_.ATTACHMENTID as ATTACHME1_1_, itemgradin0_.ATTACHMENTID as
> ATTACHME1_198_0_, itemgradin0_.RESOURCEID as RESOURCEID198_0_,
> itemgradin0_.FILENAME as FILENAME198_0_, itemgradin0_.MIMETYPE as
> MIMETYPE198_0_, itemgradin0_.FILESIZE as FILESIZE198_0_,
> itemgradin0_.DESCRIPTION as DESCRIPT7_198_0_, itemgradin0_.LOCATION as
> LOCATION198_0_, itemgradin0_.ISLINK as ISLINK198_0_, itemgradin0_.STATUS
> as STATUS198_0_, itemgradin0_.CREATEDBY as CREATEDBY198_0_,
> itemgradin0_.CREATEDDATE as CREATED12_198_0_,
> itemgradin0_.LASTMODIFIEDBY as LASTMOD13_198_0_,
> itemgradin0_.LASTMODIFIEDDATE as LASTMOD14_198_0_,
> itemgradin0_.ITEMGRADINGID as ITEMGRA15_198_0_ from
> SAM_GRADINGATTACHMENT_T itemgradin0_ where itemgradin0_.ITEMGRADINGID=?
> order by itemgradin0_.createdDate asc
>
> but if that object is changed to lazy loading like this:
>
> Index:
>
> samigo-hibernate/src/java/org/sakaiproject/tool/assessment/data/dao/grading/GradingData.hbm.xml
> ===================================================================
> ---
>
> samigo-hibernate/src/java/org/sakaiproject/tool/assessment/data/dao/grading/GradingData.hbm.xml
>    (revision 107894)
> +++
>
> samigo-hibernate/src/java/org/sakaiproject/tool/assessment/data/dao/grading/GradingData.hbm.xml
>    (working copy)
> @@ -28,7 +28,7 @@
>     <property name="lastDuration" type="string" length="36"
> column="LASTDURATION" not-null="false" />
>
>        <set name="itemGradingAttachmentSet"
> table="SAM_GRADINGATTACHMENT_T" cascade="all" order-by="createdDate
> asc"
> -        inverse="true" lazy="false">
> +        inverse="true" lazy="true">
>         <cache usage="read-write"/>
>         <key column="ITEMGRADINGID"/>
>         <one-to-many
>
> class="org.sakaiproject.tool.assessment.data.dao.grading.ItemGradingAttachment"/>
>
> then all those Prepare statements do not get issued, and the
> performance is much better (by 400ms+ per request towards the end of the
> assessment).
>
> What feature is SAM_GRADINGATTACHMENT_T used for? In our production
> database, this only has 3 rows so it's presumably not much used.
>
> Is there any reason not to switch it to lazy=true or functionality that
> should be QA'd if we do so?
>
> Regards
> Stephen
>
> Stephen Marquard, Acting Director
> Centre for Educational Technology, University of Cape Town
> http://www.cet.uct.ac.za
> Email/IM/XMPP: stephen.marquard at uct.ac.za
> Phone: +27-21-650-5037 Cell: +27-83-500-5290
>
>
>
> >>> "Stephen Marquard" <stephen.marquard at uct.ac.za> 5/6/2012 8:04 PM
> >>>
> Hi all,
>
> Unfortunately I was mistaken about this issue being resolved in 2.9 (I
> was misled by an error in a JMeter test). Both 2.9 and trunk still
> show
> increasing response times as the test progresses. This is related to
> the
> action of saving the answer. In a test where no answers are saved
> (just
> moving on to the next question), the response time is constant.
>
> So we don't have an answer yet and are going to continue looking into
> the code. Any suggestions welcome.
>
> Regards
> Stephen
>
>
> Stephen Marquard, Acting Director
> Centre for Educational Technology, University of Cape Town
> http://www.cet.uct.ac.za
> Email/IM/XMPP: stephen.marquard at uct.ac.za
> Phone: +27-21-650-5037 Cell: +27-83-500-5290
>
>
>
> >>> "Stephen Marquard" <stephen.marquard at uct.ac.za> 5/3/2012 9:22 PM
> >>>
> Hi all,
>
> We have been doing some performance and load testing of T&Q for large
> assessments (160 and 400 questions) with JMeter, and have identified
> one
> specific issue which is that in 2.8, the response time per item
> submission increases as the test progresses (e.g. submitting answer to
> Q1 could take 100ms but for Q160 the response time is 500ms).
>
> The good news is that this behaviour is no longer present in 2.9 and
> trunk - the response time is the same no matter where you are in the
> test.
>
> So two followup questions:
>
> 1. Is anyone aware of a specific JIRA / code change between 2.8 and
> 2.9
> that would have fixed this issue? (As if so, we would consider merging
> this to a local 2-8-x branch).
>
> 2. How much testing has the 2.9 T&Q release candidate had, and would
> you consider it ready to run in production?
>
> Regards
> Stephen
>
>
>
> Stephen Marquard, Acting Director
> Centre for Educational Technology, University of Cape Town
> http://www.cet.uct.ac.za
> Email/IM/XMPP: stephen.marquard at uct.ac.za
> Phone: +27-21-650-5037 Cell: +27-83-500-5290
>
>
>
>
>
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