[Building Sakai] Heavy Samigo query

Mon Oct 17 06:12:38 PDT 2011

That would be absolutely fantastic.  We didn't survive last night, too
may of these queries piling up by the time we hit peak loads.

Here are two more queries that were really stinging:

select publisheds0_.ASSESSMENTID as col_0_0_ from SAM_PUBLISHEDSECTION_T
publisheds0_, SAM_PUBLISHEDSECTIONMETADATA_T publisheds1_ where
publisheds0_.SECTIONID=publisheds1_.SECTIONID and
publisheds1_.LABEL='AUTHOR_TYPE' and publisheds1_.ENTRY='2' group by
publisheds0_.ASSESSMENTID

select assessment0_.PUBLISHEDASSESSMENTID as col_0_0_,
count(assessment0_.ASSESSMENTGRADINGID) as col_1_0_ from
SAM_ASSESSMENTGRADING_T assessment0_ group by
assessment0_.PUBLISHEDASSESSMENTID

The 2nd one doesn't even have a where statement.

We absolutely need to limit these queries to query by SITE_ID so we are
only pulling exams for just the one site the user is in.

There are probably other queries that aren't limited by SITE_ID, ideally
all queries would be.

I will open a JIRA ASAP.  If at all possible we would be able to get
these changes in by next Saturday so we can hopefully survive next
Sunday.

From: ktsao at hungs.org [mailto:ktsao at hungs.org] On Behalf Of Karen Tsao
Sent: Monday, October 17, 2011 2:28 AM
To: Kusnetz, Jeremy
Cc: sakai-dev
Subject: Re: [Building Sakai] Heavy Samigo query

Hi Jeremy,

I think I found where that query got executed. Can you please log a Jira
for this issue? I will work on the fix and might need your help to
verify it once I am done.

Thanks,
Karen

On Fri, Oct 14, 2011 at 5:14 PM, Kusnetz, Jeremy <JKusnetz at apus.edu>
wrote:

FYI, comparing the code in 2.6.3 to 2.8 it appears that the first query
has been fixed in 2.8 (it adds querying by the SITE_ID), but this one
below still doesn't have any kind of where and will return all rows for
SAM_PUBLISHEDFEEDBACK_T, which in our case is currently over 50K and
will return all this data each time a user enters the tool.

From: Kusnetz, Jeremy 
Sent: Wednesday, October 12, 2011 9:15 AM
To: Kusnetz, Jeremy; sakai-dev
Subject: RE: [Building Sakai] Heavy Samigo query

Here is another one:

EXPLAIN 

select publishedf0_.ASSESSMENTID as col_0_0_,
publishedf0_.FEEDBACKDELIVERY as col_1_0_,
publishedf0_.FEEDBACKAUTHORING as col_2_0_, publishedf0_.EDITCOMPONENTS
as col_3_0_, publishedf0_.SHOWQUESTIONTEXT as col_4_0_,
publishedf0_.SHOWSTUDENTRESPONSE as col_5_0_,
publishedf0_.SHOWCORRECTRESPONSE as col_6_0_,
publishedf0_.SHOWSTUDENTSCORE as col_7_0_,
publishedf0_.SHOWSTUDENTQUESTIONSCORE as col_8_0_,
publishedf0_.SHOWQUESTIONLEVELFEEDBACK as col_9_0_,
publishedf0_.SHOWSELECTIONLEVELFEEDBACK as col_10_0_,
publishedf0_.SHOWGRADERCOMMENTS as col_11_0_,
publishedf0_.SHOWSTATISTICS as col_12_0_ from SAM_PUBLISHEDFEEDBACK_T
publishedf0_

______ Sub-Part 1 _______

Select Type: SIMPLE      

      Table: publishedf0_

Partitions:             

       Type: ALL         

 Poss. Keys:             

      Index:             

 Key Length:             

  Index Ref:             

  Row Count: 45745       

    Special:             

Press e to explain, f for full query, o for optimized query

I'm worried that these queries are not even doing any kind of where's so
they are just doing full table scans.

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
<http://www.apus.edu> 

From: sakai-dev-bounces at collab.sakaiproject.org
[mailto:sakai-dev-bounces at collab.sakaiproject.org] On Behalf Of Kusnetz,
Jeremy
Sent: Wednesday, October 12, 2011 9:13 AM
To: sakai-dev
Subject: [Building Sakai] Heavy Samigo query

One of the queries that we see piling up during high load is the
following (this is from innotop).  We heavily utilize Samigo, with
thousands of active classrooms, many with a dozen or more assessments.
This is on CLE 2.6.3

EXPLAIN 

select publishede0_.ASSESSMENTID as col_0_0_, publishede0_.SCORINGTYPE
as col_1_0_, publisheda1_.SUBMISSIONSALLOWED as col_2_0_ from
SAM_PUBLISHEDEVALUATION_T publishede0_, SAM_PUBLISHEDACCESSCONTROL_T
publisheda1_ where publishede0_.ASSESSMENTID=publisheda1_.ASSESSMENTID

_____________ Sub-Part 1 ______________  __________________ Sub-Part 1
__________________

Select Type: SIMPLE                      Select Type: SIMPLE

      Table: publishede0_                      Table: publisheda1_

 Partitions:                              Partitions:

       Type: ALL                                Type: eq_ref

 Poss. Keys: PRIMARY,FK94CB245F9482C945   Poss. Keys:
PRIMARY,FK2EDF39E09482C945         

      Index:                                   Index: PRIMARY

 Key Length:                              Key Length: 8

  Index Ref:                               Index Ref:
sakai_300.publishede0_.ASSESSMENTID

  Row Count: 45874                         Row Count: 1

    Special:                                 Special:

Press e to explain, f for full query, o for optimized query

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
<http://www.apus.edu> 

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