[Building Sakai] Oracle Row Lock Contention During Samigo and Message Center Queries

[Stoufer,R M]

Hello Everyone,

During the past couple of days we have experienced spikes in our normal database activity which have resulted in 'row lock contention' messages on our Oracle database.

We are using: Sakai 2.6.x, Samigo 2.7.x, Msg Ctr 2.7.x, Oracle 11g R2

The culprit SQLs are the following:


update SAM_ITEMGRADING_T set ASSESSMENTGRADINGID=:1 , PUBLISHEDITEMID=:2

, PUBLISHEDITEMTEXTID=:3 , AGENTID=:4 , SUBMITTEDDATE=:5 ,

PUBLISHEDANSWERID=:6 , RATIONALE=:7 , ANSWERTEXT=:8 , AUTOSCORE=:9 ,

OVERRIDESCORE=:10 , COMMENTS=:11 , GRADEDBY=:12 , GRADEDDATE=:13 ,

REVIEW=:14 , ATTEMPTSREMAINING=:15 , LASTDURATION=:16 where

ITEMGRADINGID=:17

and


select messageimp0_.ID as ID17_, messageimp0_.VERSION as VERSION17_,

messageimp0_.UUID as UUID17_, messageimp0_.CREATED as CREATED17_,

messageimp0_.CREATED_BY as CREATED6_17_, messageimp0_.MODIFIED as

MODIFIED17_, messageimp0_.MODIFIED_BY as MODIFIED8_17_,

messageimp0_.TITLE as TITLE17_, messageimp0_.BODY as BODY17_,

messageimp0_.AUTHOR as AUTHOR17_, messageimp0_.HAS_ATTACHMENTS as

HAS12_17_, mess...


The Samigo update statement caused our average

database load to be about 50x normal. Oracle describes it as,

'Significant row contention was detected in the TABLE

"SAKAI.SAM_ITEMGRADING_T".'

Does anyone have any insight as to what may be going on?  We are approaching final exams in a week and would like to get this resolved ASAP.

Thanks!

R. Michael Stoufer
Academic Technology - ICS
University of Florida

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