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DCC/DW or LQE -- when are they used


Mahari Hill (482164180) | asked Jan 20 '17, 7:27 a.m.

Hello,

When creating reports, when do you know if you are using DCC/DW or LQE for the report? Is it if you are using SQL (Advanced) you are using LQE, or is it something else?

I ask b/c I was going through the tutorial here:

https://jazz.net/library/article/1562

Custom trend reports using work item history

And there is a section that asks you to edit the table/columns - done, previewed the report, great. Then it asks for you to  look at the Graph to edit -- no response. Instead, my server received two core dumps of 50GB and a LQE log file of 26GB rendering the server unreachable as it ran out of space..

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Francesco Chiossi (5.7k1719) | answered Jan 20 '17, 9:49 a.m.

Hello Mahari,

LQE is very resource hungry, the symptoms you describe makes me think of not enough resources assigned to LQE.

The recommendation for LQE is to have a dedicated computer with adequate CPU, memory and hard drive capacity. See the following article for more details:

Best Practices for Configuring LQE For Performance and Scalability
https://jazz.net/wiki/bin/view/Deployment/LifecycleQueryEngineBestPractices

Best Regards
Francesco Chiossi


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Francesco Chiossi (5.7k1719) | answered Jan 20 '17, 7:46 a.m.

Hello Mahari,

this is where you select which data source your report will use:


Note: in the Advanced section you will see SQL queries for data warehouse reports and SPARQL queries for LQE reports.

Best Regards
Francesco Chiossi


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Mahari Hill commented Jan 20 '17, 9:30 a.m.

Thanks for responding. I guess my question forms from why LQE got out of control. I am not sure I did anything to cause the lqe.log file to jump to 26GB.


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Ernest Mah (611) | answered Jan 20 '17, 10:01 a.m.
JAZZ DEVELOPER

The log4j.properties has a default 10MB size on the log file and a limit on the number of log files to keep.  This controls the size of the lqe.log as well as the number of backups kept (on a rotating basis)

log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=5

It is not uncommon for the indexTDB folder to grow to larger sizes as it is indexing data from all of the connected CLM applications if you configured LQE through JTS setup.

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