Date: Fri, 16 Dec 2005 14:24:21 +0800 From: huang leo <leo.huang.gd@gmail.com> To: Greg 'groggy' Lehey <grog@freebsd.org> Cc: freebsd-performance@freebsd.org Subject: Re: Benchmark MySQL Performance On FreeBSD And Linux Message-ID: <a0cd7c070512152224m6304f398q@mail.gmail.com> In-Reply-To: <20051216040722.GA503@wantadilla.lemis.com> References: <a0cd7c070512151920s67ca6cd6h@mail.gmail.com> <20051216040722.GA503@wantadilla.lemis.com>
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hi, I experience the crashes myself. I used super-smack remotely to connect MySQL with 200 clients first. After the test was done and the connections were closed, we connected MySQL with 300 clients immediately. Then the MySQ= L restarted. The error log of MySQL is: mysqld in free(): error: modified (chunk-) pointer 051130 10:12:04 mysqld restarted I think that it's time out to cause the deadlocks, because our MySQL's innodb_lock_wait_timeout is 50. As you can see from our paper, we used super smack to test. The test script= s were given in the paper. Best regards, Leo Huang 2005/12/16, Greg 'groggy' Lehey <grog@freebsd.org>: On Friday, 16 December 2005 at 11:20:12 +0800, huang leo wrote: > > We had evaluated MySQL performance on FreeBSD and Linux. The result is > attached. Thank you! This is some of the most plausible information I've seen in a while. I'm forwarding it to a MySQL internal list, and I expect we'll discuss it in much detail. A few comments: - You refer to bug http://bugs.mysql.com/bug.php?12251. Did you experience these crashes yourself? If you look through that bug report, you'll find that we (MySQL) have had great difficulty reproducing the problem. Many people have reported that they have no trouble under the same conditions, and we were half thinking it might be related to (but not the fault of) the hardware in question. Your hardware is very different, so it would help us a lot if you're also able to reproduce it. - There's been a lot of discussion on the FreeBSD lists recently suggesting that the performance problems are related to the choice of timer. I've never been convinced, and your results suggest to me that this isn't the real problem. Still, it would be nice to compare the results using various timer options. If you haven't been following the discussion, it's in the archives for the FreeBSD-current mailing list. Let me know (in private mail) if you'd like me to forward them to you. - I'd be very interested in the deadlocks you've been experiencing. If you have any additional information, please let me know. Do you have scripts for these tests? I appreciate that the information is mainly there, but it would be easier for us if the scripts are available. Thanks again for the report Greg -- See complete headers for address and phone numbers
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