not clear on how to calculate the wait time

I am reading on TOm Kyte performance tuning workshop and I am not on this on top 5 events on statspack report:

Code:

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events                      wait        time          %Total elapsed

Direct path write            5168        279          20.5

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and he mentioned that there was 120 waits for direct path writes, totalling three thousandth second (as opposed to 279 seconds)

the question is how does he get 120 waits and 3,000 second???

Quote:

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Originally posted by learning_bee
I am reading on TOm Kyte performance tuning workshop and I am not on this on top 5 events on statspack report:

Code:

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events                      wait        time          %Total elapsed

Direct path write            5168        279          20.5

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and he mentioned that there was 120 waits for direct path writes, totalling three thousandth second (as opposed to 279 seconds)

the question is how does he get 120 waits and 3,000 second???

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link?

Davey,

I found the PFD file from one of the thread in this forum and unfortunately, I don't remember which thread it's on; however I have the PDF file and please see the attached file on STATSPACK portion.

thanks,

unfortunately, I can't upload pdf neither the zip file b/c it's too big. Anyway, attached is the snapshot of what he said

NEVER EVER LOOK INTO THE TOP 5 EVENTS OF STATSPACK REPORT.
THEY ARE ALL WRONG


Tamil

tamilselvan,

I am confused, I read so many docs and even Tom Kyte mentioned that top 5 events is one of the most important areas, plus some of the guys who really knows what they are doing in here would say the same thing.

Please let me know b/c I don't want to keep doing the wrong thing.

Quote:

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Originally posted by learning_bee
and he mentioned that there was 120 waits for direct path writes, totalling three thousandth second (as opposed to 279 seconds)

the question is how does he get 120 waits and 3,000 second???

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These were the values after making changes (pga_aggregate_taget) - he does not show the new report.

Quote:

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Originally posted by tamilselvan

NEVER EVER LOOK INTO THE TOP 5 EVENTS OF STATSPACK REPORT.
THEY ARE ALL WRONG


Tamil

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you can't say that and not qualify your statements with examples

I can't update the whole pdf file for your guys and it's so annoying to capture and miss some other part, any way, I captured the 5 events after making the changes.

I still like to undertand how to calculate those numbers

Read it very carefully: three reports are mentioned, he prints #1 and #3. You'll just have to take his word about report #2.