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If I use DBMS_Profiler to profile a long running (5 hour) PL/SQL script, how much longer should I expect the script to run with profiling? I realize this will be dependent on what the script is doing, but in general am I looking at seconds, minutes, or perhaps more?

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I have used DBMS_PROFILER on 9i and 10g a bit. Depending on the code I have seen between 2% and 10% time penalty for profiling.

Luckily the profiler was built to cache results in memory and flush to disk infrequently. I think it depends more on number of lines executed rather than the total wall clock time of the profiler - since that is what the profiler is watching anyway.

-Dave

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My testing seems to confirm this. Code blocks that do equivalent work with fewer lines of code have lower overhead that those doing the same work with more lines of code. – Leigh Riffel Feb 28 '12 at 19:42
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The best way to find out will be to run some known code samples with and without using the profiler. The differences normally should not be much but indeed can vary. Even dbms_application_info can hurt when put inside a high frequent loop.

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I can certainly do that for a smaller block of code and extrapolate the results, but I was hoping that someone had actually run this on a long running procedure and noticed either a) Very little difference in run time. or b) It increased the run time by xx%. Thank you for your answer though. – Leigh Riffel Feb 28 '12 at 14:17
My testing indicates a 10% to 14% increase in time for blocks of code taking less than 15 seconds. – Leigh Riffel Feb 28 '12 at 19:39

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