Hi.
On Wed 2002-10-30 at 10:20:05 -0800, [EMAIL PROTECTED] wrote:
> >Heath, I once had similar symptoms when my DNS resolving had problems
> >and all new connections "slept" for some seconds while they were
> >waiting for an response. My work-around was to use --skip-name-resolve
> >until the DNS problem was solved.
>
> Benjamin,
>
> Thanks for the suggestion but the connections are made quickly.
Well, I said, I did not imply that you experience the same
problem. And I did say so, because your symptoms sounds similar, but
not the same.
Regardless, the vmstat output strongly suggests that your machine
spends most time in a blocking state, waiting for something.
> How did you diagnose the cause of the blocked processes?
Well, that was a rather huge, 3-week battle with a lot of trial and
error (because the problem occured only sporadically and only on the
producation machine). So there is no step-by-step suggestion I can
give.
You said, the connections are made quickly, but IIRC, you get about 15
reqeusts per seconds in the bad case. Well, that makes 0.06 seconds
per connection, which surely looks "quickly" to a human observer.
In your situation I would go and write a minimal test program which
tries to trigger the behaviour. It should have timings for the
different parts (open, query, close, ...). Then you can go and test it
on the server. Retry with no concurrent accesses by other programs.
Try on a different machine. Try to be sure that it's indeed mysqld
which is not answering and not the client part "losing" the time. And
so on. Maybe use a profiler to determine in which function mysqld
stays the most time.
In other words: Try to track down, in which part the time is spend.
> Here is our SHOW STATUS
[...]
AFAICT, everything looks normal.
Regards,
Benjamin.
--
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