From Bugzilla Helper: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5 Description of problem: Installed mysql on a a dual-core, dual-processor-system running latest FC4 on x86_64. Though on the previous system running mysql with 32-bit several processes showed up and were distributed across multiple processors, now there is only one mysql-processes e.g. showing up in top, and it's only using cpu-time from one cpu. Could this be an issue with mysql not being built for SMP-systems or something? 400 mysql-connections connected, all executing queries. I see 400 threads running, but only one mysql-process, and that's only running on one and the same cpu all the time. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1.Run mysql on FC4-system on x86_64 with multiple processors 2. 3. Additional info:
You'd probably have better luck filing this at www.mysql.com; I don't know their code nearly well enough to guess what the issue might be. In any case, not supplying the exact package version is a faux pas. "Latest FC4" is meaningless.
Sorry for that. The versions installed are: mysql-4.1.15-1.FC4.1 mysql-server-4.1.15-1.FC4.1 I looked it up: The system on which mysql was running fine with multiple proceessors was FC3. However, since there were no mysql 4.x-packages for FC3, the packages from MySQL themselves were used. Is there any compile-flag that might have been used when packaging the RPM to disable the use of multiple processes/processors?
Nope ... not intentionally, anyway ... If you can give me a pointer to the exact SRPM for the MySQL version you were using on the previous system, I could compare flags to see if anything turns up.
Stefan, you mention that in FC-3, you used packages from MySQL itself. Were thse mysql-4 packages you picked from www.mysql.com ? These were on a 32-bit system, as well? And on FC-4, you're using mysql packages provided by Fedora, right? And these are on a x86_64 system? As Tom has suggested, please provide the exact SRPM that you were using (if this was from mysql.com, we can probably get that online).
During nightly maintainence we switched to the RPMs directly from MySQL. Those still run on one processor only. Maybe it has to do with MySQL building on 64-bit. I'll get back to this thread as soon as we hear back from MySQL. Thread at MySQL-bugsystem: http://bugs.mysql.com/bug.php?id=15661
Closing as UPSTREAM, since this has been properly reported to upstream developers.
Just for your information: Seems it was no real issue. On the newer system the kernel seems to load-balance across CPUs differently. While only lightly loaded utilisation stays on one CPU, spreads as load rises.
Great, I'll re-mark as NOTABUG then. Many thanks for following up on it.