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From:Michael Widenius Date:March 18 2009 2:23pm
Subject:Re: [Maria-developers] Working on microsecond patches
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Hi!

>>>>> "Vadim" == Vadim Tkachenko <vadim@stripped> writes:

Vadim> Michael,
Vadim> Thread-pool should be used very carefully.

Vadim> We tested it and InnoDB hangs in sysbench benchmarks when count of
Vadim> client connection > size of thread-pool.

Yes, this a problem when you have more locks than threads.
The innodb deadlock detector has to timeout the hanged items.

Vadim> The problem is transaction state. Some connections may do internals
Vadim> locks and after that could not enter to pool, because all slots are busy.
Vadim> I expect you will have the same problem with Maria when it can fully
Vadim> support transactions.

That is one of the main reasons I added --extra-port to MariaDB
This allows you to connect and check/kill things if you get a hang.

So things are not perfect now, but at least a little better.

In the future we have to also look at creating more pool-threads when
all pool-threads gets locked by a handler.

Regards,
Monty
Thread
Working on microsecond patchesMichael Widenius13 Mar
  • Re: [Maria-developers] Working on microsecond patchesVadim Tkachenko13 Mar
    • Re: [Maria-developers] Working on microsecond patchesMichael Widenius18 Mar
      • Re: [Maria-developers] Working on microsecond patchesJeremiah Gowdy18 Mar
        • Re: [Maria-developers] Working on microsecond patchesMichael Widenius8 Apr
      • Re: [Maria-developers] Working on microsecond patchesMARK CALLAGHAN18 Mar
        • Re: [Maria-developers] Working on microsecond patchesMichael Widenius8 Apr
          • Re: [Maria-developers] Working on microsecond patchesMARK CALLAGHAN9 Apr