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Monday, 16 July 2012

IDENTIFICATION OF BOTTLENECKS

IDENTIFICATION OF BOTTLENECKS
Performance of Informatica is dependant on the performance of its several components like database, network, transformations, mappings, sessions etc. To tune the performance of Informatica, we have to identify the bottleneck first.
Bottleneck may be present in source, target, transformations, mapping, session,database or network. It is best to identify performance issue in components in the order source, target, transformations, mapping and session. After identifying the bottleneck, apply the tuning mechanisms in whichever way they are applicable to the project.
Identify bottleneck in Source
If source is a relational table, put a filter transformation in the mapping, just after source qualifier; make the condition of filter to FALSE. So all records will be filtered off and none will proceed to other parts of the mapping.In original case, without the test filter, total time taken is as follows:-
Total Time = time taken by (source + transformations + target load)
Now because of filter, Total Time = time taken by source
So if source was fine, then in the latter case, session should take less time. Still if the session takes near equal time as former case, then there is a source bottleneck.
Identify bottleneck in Target
If the target is a relational table, then substitute it with a flat file and run the session. If the time taken now is very much less than the time taken for the session to load to table, then the target table is the bottleneck.
Identify bottleneck in Transformation
Remove the transformation from the mapping and run it. Note the time taken.Then put the transformation back and run the mapping again. If the time taken now is significantly more than previous time, then the transformation is the bottleneck.
But removal of transformation for testing can be a pain for the developer since that might require further changes for the session to get into the ‘working mode’.
So we can put filter with the FALSE condition just after the transformation and run the session. If the session run takes equal time with and without this test filter,then transformation is the bottleneck.
Identify bottleneck in sessions
We can use the session log to identify whether the source, target or transformations are the performance bottleneck. Session logs contain thread summary records like the following:-
MASTER> PETL_24018 Thread [READER_1_1_1] created for the read stage of partition point [SQ_test_all_text_data] has completed: Total Run Time =[11.703201] secs, Total Idle Time = [9.560945] secs, Busy Percentage =[18.304876].
MASTER> PETL_24019 Thread [TRANSF_1_1_1_1] created for the transformation stage of partition point [SQ_test_all_text_data] has completed: Total Run Time = [11.764368] secs, Total Idle Time = [0.000000] secs, Busy Percentage = [100.000000].
If busy percentage is 100, then that part is the bottleneck.
Basically we have to rely on thread statistics to identify the cause of performance issues. Once the ‘Collect Performance Data’ option (In session ‘Properties’ tab) is enabled, all the performance related information would appear in the log created by the session.

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