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From:Ed Carp Date:February 2 2002 8:16am
Subject:RE: MySQL Clients Hang
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> >> I have not completely figured out what the problem is and I never got a
> >> response from any one else on the list.  I can tell you it looks like a
> >> mutex problem between two threads.  We have followed it down into
> >> pthreads
> >> where it seems to be stuck.  The external symptom we see is that
> >> the MySQL
> >> server does not open any of the databases.
> >>
> >> The really bad news is that it is not a MySQL problem so
> >> reinstalling MySQL
> >> does nothing to fix it.  The worse news is that the MySQL
> server does not
> >> give you a clue what the problem is.

> We had a Linux guru look at the version of mysql on this system that we
> compiled with debug.  I got information about the debugging session third
> hand and really don't have any details other than the problem appeared to
> be in pthreads.  I am not so sure pthreads is at fault other than a
> dead-lock condition exists and it is not detecting it and blowing one of
> the stuck processes away.

What version of Linux are you running?  After a lot of reearch and gdb'ing,
I found a bug report in bugzilla on redhat.com that seems to illustrate the
bug that we're having:
http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=13785

In short, it seems it's a contention problem in pthread_lock. the fix is to
upgrade to libc 2.1.92 (or better).  RedHat 6.2 is running libpthreads 0.8,
and I think this problem is fixed in 0.9.  Unfortuantely, 0.9 needs libc
2.2, so you're probably better off upgrading to RedHat 7.2.

I know, this bug report applies to SMP kernels, but ieven if you're not
running an SMP kernel, it's probably a good idea to upgrade anyway.

Why it started suddenly and won't go away, I have no idea.

Thread
MySQL Clients HangBill MacAllister14 Jan
re: MySQL Clients HangBill MacAllister28 Jan
RE: MySQL Clients HangBill MacAllister29 Jan
  • RE: MySQL Clients HangEd Carp29 Jan
    • RE: MySQL Clients HangBill MacAllister29 Jan
  • RE: MySQL Clients HangEd Carp2 Feb
    • RE: MySQL Clients HangBill MacAllister4 Feb