Re: MySQL and NPTL
SQL I have the problem like this under FreeBSD 5.2 with libkse (kernel threads). Server with high loading doesn't want to shutdown. But server with low loading does. Steve, I have had this same problem exept the entire server does not hang, only one thread which experiences a signficiat slowdown. This happens a couple times a week for our 4 servers. I believe this is a thread scheduling issue. The mysql support team suggests against using NPTL. However, I use mysqld-max on redhat linux 9.0 and have found a 10-20% performance difference at HIGH (hundreds of connections) load levels. The support team claims the difference in performance between linux threads and NPTL is never significant. Incidentally I have experinced this same thread starvation issue on redhat as 3.0 amd64 while using Linux threads. Theory is that glic 2.3 is to blame ( redhat 9.0 - glibc-2.3.2-11.9 , redhat as 3.0 - glibc-2.3.2-95.6 ). So the version of glibc looks to be the culprit. As I understand it Mysql is working with Redhat to determine the issues with glibc 2.3. I haven't tried the export line. Trevor Steve Meyers wrote: Has anyone else experienced this bug? http://bugs.mysql.com/bug.php?id=868 We've been seeing this problem on several of our servers (see the last comment to the bug). MySQL just hangs occasionally, it happens about 3-4 times per month. We have 13 database servers, so that unfortunately increases our odds. I just wondered how many other people have seen it, and if the suggested export LD_ASSUME_KERNEL=2.2.5; mysqld_safe has worked for anyone. In order to turn that on, I will need to take our site down completely, which is (of course) not desirable. Thanks! Steve Meyers -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED] Best regards. ___ Andrey Kotrekhov [EMAIL PROTECTED] ISP Alkar Teleport . +380 562 34-00-44 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
MySQL and NPTL
Has anyone else experienced this bug? http://bugs.mysql.com/bug.php?id=868 We've been seeing this problem on several of our servers (see the last comment to the bug). MySQL just hangs occasionally, it happens about 3-4 times per month. We have 13 database servers, so that unfortunately increases our odds. I just wondered how many other people have seen it, and if the suggested export LD_ASSUME_KERNEL=2.2.5; mysqld_safe has worked for anyone. In order to turn that on, I will need to take our site down completely, which is (of course) not desirable. Thanks! Steve Meyers -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL and NPTL
Steve Meyers wrote: Has anyone else experienced this bug? http://bugs.mysql.com/bug.php?id=868 We've been seeing this problem on several of our servers (see the last comment to the bug). MySQL just hangs occasionally, it happens about 3-4 times per month. We have 13 database servers, so that unfortunately increases our odds. I just wondered how many other people have seen it, and if the suggested export LD_ASSUME_KERNEL=2.2.5; mysqld_safe has worked for anyone. In order to turn that on, I will need to take our site down completely, which is (of course) not desirable. Steve: I have not heard much good about NPTL threads when used with MySQL at least :-) If LD_ASSUME_KERNEL trick does not do the job, I would recommend compiling a virgin 2.4 kernel from kernel.org and putting it on all of your servers. That might actually be a good idea anyway even if the trick does work. In three years of doing MySQL support I have learned this simple formula: RH kernel from 7.0 and newer + MySQL + high load = highly probable instability -- Sasha Pachev Create online surveys at http://www.surveyz.com/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL and NPTL
Steve, I have had this same problem exept the entire server does not hang, only one thread which experiences a signficiat slowdown. This happens a couple times a week for our 4 servers. I believe this is a thread scheduling issue. The mysql support team suggests against using NPTL. However, I use mysqld-max on redhat linux 9.0 and have found a 10-20% performance difference at HIGH (hundreds of connections) load levels. The support team claims the difference in performance between linux threads and NPTL is never significant. Incidentally I have experinced this same thread starvation issue on redhat as 3.0 amd64 while using Linux threads. Theory is that glic 2.3 is to blame ( redhat 9.0 - glibc-2.3.2-11.9 , redhat as 3.0 - glibc-2.3.2-95.6 ). So the version of glibc looks to be the culprit. As I understand it Mysql is working with Redhat to determine the issues with glibc 2.3. I haven't tried the export line. Trevor Steve Meyers wrote: Has anyone else experienced this bug? http://bugs.mysql.com/bug.php?id=868 We've been seeing this problem on several of our servers (see the last comment to the bug). MySQL just hangs occasionally, it happens about 3-4 times per month. We have 13 database servers, so that unfortunately increases our odds. I just wondered how many other people have seen it, and if the suggested export LD_ASSUME_KERNEL=2.2.5; mysqld_safe has worked for anyone. In order to turn that on, I will need to take our site down completely, which is (of course) not desirable. Thanks! Steve Meyers -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL and NPTL
Sasha Pachev said: Steve Meyers wrote: Has anyone else experienced this bug? http://bugs.mysql.com/bug.php?id=868 We've been seeing this problem on several of our servers (see the last comment to the bug). MySQL just hangs occasionally, it happens about 3-4 times per month. We have 13 database servers, so that unfortunately increases our odds. I just wondered how many other people have seen it, and if the suggested export LD_ASSUME_KERNEL=2.2.5; mysqld_safe has worked for anyone. In order to turn that on, I will need to take our site down completely, which is (of course) not desirable. Steve: I have not heard much good about NPTL threads when used with MySQL at least :-) If LD_ASSUME_KERNEL trick does not do the job, I would recommend compiling a virgin 2.4 kernel from kernel.org and putting it on all of your servers. That might actually be a good idea anyway even if the trick does work. In three years of doing MySQL support I have learned this simple formula: RH kernel from 7.0 and newer + MySQL + high load = highly probable instability -- Sasha Pachev Create online surveys at http://www.surveyz.com/ Any particular reason to use 2.4.x vs 2.6.x from kernel for base? -- William R. Mussatto, Senior Systems Engineer Ph. 909-920-9154 ext. 27 FAX. 909-608-7061 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: MySQL and NPTL
Any particular reason to use 2.4.x vs 2.6.x from kernel for base? 2.6 has not been around long enough to prove itself, in my opinion. I know 2.4 will work well, but I cannot say the same about 2.6 with the same degree of confidence. -- Sasha Pachev Create online surveys at http://www.surveyz.com/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
