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Thursday, April 21, 2011

AWR Analysis - Parse CPU to Parse Elapsd %

Under AWR’s Instance Efficiency Percentages - Parse CPU to Parse Elapsd % is one area which is more confusing and clear information will not be available. Information below talks clearly on how to we interpret the ratio.

• If you spend 1 CPU second on CPU to parse but total elapsed is 5 second wall clock time then it means you are waiting on some resources to complete the parsing.

• Ideally Parse Elapsed must be equal to Parse CPU, i.e., only CPU time is used for parsing. In that case the ratio is 100%. If wait time is more than the ratio will be less.


 
(8879/110582)*100=8.03%
What does it mean and how it is being interpreted
• Parse CPU to Parse Elapsd %: 8.03
• It is percentage. 8.03% means .0803
• If you divide it by 1 then 1/.0803 = 12.45
• Which means 12.45 second (wall clock time) must be elapsed for every cpu second for parsing. Its not   
   good.
• It represents resource contention while parsing.Low Value for this ratio is an indicator of latching problem. Investigate the latch sections in AWR report for contention on library cache and shared pool latches.





4 comments:

Walter said...

One of the best explanation with example!

Anonymous said...

Great explanation

Anonymous said...

Thanks for sharing such wonderful articles on AWR. Its really helps in understanding the AWR report. I have search a lot in google but such a great amount of information on AWR found nowhere.


Really appreciated.

Raj Kumar Kushwaha said...

Great.

I have this AWR report, Could you please explain me about Parse CPU to Parse Elapsd % and Execute Parse looks good or not.


Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 99.81 In-memory Sort %: 100.00
Library Hit %: 99.80 Soft Parse %: 99.93
Execute to Parse %: 11.13 Latch Hit %: 99.98
Parse CPU to Parse Elapsd %: 80.02 % Non-Parse CPU: 93.46


Thanks,

Raj Kumar

rajsoft8899@gmail.com