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From:Michael Widenius Date:March 9 2000 1:14am
Subject:A bug in 3.23.12c
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>>>>> "Peter" == Peter Zaitsev <pz@stripped> writes:

Peter> Having troble with mysql 3.23.12c running on LINUX 2.2.14 (Suse 6.3) on PIII
Peter> SMP compiled as static with GCC 2.95.2

Peter> I never had this problem with 3.23.10 then have runned it for several weeks,
Peter> there it has some other bugs which does not allow me to switch back to it.
Peter> The problem is - sometimes (I got this problems twice in 48 hours) In a
Peter> moment I get MYSQLD hanged on disk writes or so on - some queries to heap
Peter> tables pass but others does not. The top shows one of processes of MYSQLD
Peter> trying to hog all cpu (probably thread manager ?), all other processes of
Peter> mysqld are locked running in rt_sigsuspend. DISKIO is on zero level. I can't
Peter> sutdown mysqld - nor mysqladmin shutdown nor kill helps - mysqld momentaly
Peter> stops open the queries but does not shutdown. Kill -9 helped of couse.

Peter> Here is some information I can provide to help to find more sertain bug
Peter> location:


The big number of threads is probably because some thread got stuck.

To be able to fix this I would either need a backtrace of all threads
when this happens or some simple test program to be able to simulate

The only bug I know if in 3.23.12 is that you should not drop a table
that you have a LOCK TABLES on, if you are locking more than one
table, but I don't think this is the one you got :(

This looks like some mutex gets hold without getting freed, properly.
You may be able to find this by recompiling MySQL with

This will print to the .err file if MySQL detects any wrong usage of
some mutex.

Can you also check if you have some thread in a 'zombie' state
(In top these is shown as [mysqld])  This means that a thread has
crashed and this could explain the problem with stuck threads.  In
this case the problem is a bit simpler as we only need to find out why
one thread is dying...

A bug in 3.23.12cPeter Zaitsev8 Mar
  • A bug in 3.23.12cMichael Widenius9 Mar