Date: Sun, 30 Oct 2005 08:57:26 +0100 From: Stefan Cars <stefan@snowfall.se> To: Stefan Cars <stefan@snowfall.se> Cc: Greg 'groggy' Lehey <grog@FreeBSD.org>, current@freebsd.org Subject: Re: MySQL crashes on amd64 Message-ID: <43647CE6.1080703@snowfall.se> In-Reply-To: <4363DA8D.7000204@snowfall.se> References: <434CBAD5.10306@snowfall.se> <20051013010014.GG49168@wantadilla.lemis.com> <434E839B.2020209@snowfall.se> <20051014001038.GX49168@wantadilla.lemis.com> <4363DA8D.7000204@snowfall.se>
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Stefan Cars wrote: > Greg 'groggy' Lehey wrote: > >> [Sequence recovered--see http://www.lemis.com/email/email-format.html] >> >> On Thursday, 13 October 2005 at 17:56:11 +0200, Stefan Cars wrote: >> >>> Greg 'groggy' Lehey wrote: >>> >>>> On Wednesday, 12 October 2005 at 9:27:17 +0200, Stefan Cars wrote: >>>> >>>> >>>>> Hi! >>>>> >>>>> We are having troubles with MySQL 4.1 on a amd64 (it's crashing >>>>> randomly with Seg fault, signal 11. gdb bt says: Cannot access >>>>> memory at address 0x800000000000). We have got information saying >>>>> this is a 64bit related issue and should be fixed by using the i386 >>>>> version instead of amd64 (this is an Intel Xeon). >>>> >>>> >>>> Where did you get that information from? >> >> >> >> I'd still like to know an answer to this question. > > > I got information from a guy working on the floor below us, although his > thoughts were only that "amd64 is a bit unstable so that should be the > problem" > >> >> >>>>> What is the way to go when moving from amd64 to i386 ? >>>> >>>> >>>> If you mean "how do I install an i386 kernel on this machine", I can't >>>> think of any way except to start from scratch. It would be a good >>>> idea to install a separate disk, so you can access the configuration >>>> files and the database on the old disk. But before doing this, I'd be >>>> very interested in knowing what the problem is. Is the backtrace >>>> always the same? Where does it crash? >>> >>> >>> After doing some testing this is what I found out: >>> >>> 1) Exchanging memory on the machine did not work. Same error. >>> 2) Trying it on another 64 bit machine with same FreeBSD (RC1) creates >>> EXACT same problem >>> 3) Installing the i386 version of RC1 instead of amd64 on the same >>> machines and it works terrific. No crash. >> >> >> >> Hmm. That's interesting. This is obviously not a hardware issue. >> >> >>> The bt is always the same and it always crash the same, look here: >>> >>> #784 0x0000000000000000 in ?? () >>> #785 0x247c8d48002454ff in ?? () >>> #786 0x01a1c0c748006a10 in ?? () >>> #787 0x66fdebf4050f0000 in ?? () >>> #788 0x9066669066669066 in ?? () >>> #789 0x00007fffffffe778 in ?? () >>> #790 0x0000000000000006 in ?? () >>> #791 0x00007fffffffe7b0 in ?? () >>> #792 0x0000000000000017 in ?? () >>> Cannot access memory at address 0x800000000000 >> >> >> >> Without function names instead of ??, it's impossible to say what's >> happening here. You'd need to build with debug symbols. >> >> Since you've been told that this is an issue, it would be good to know >> more. As we've mentioned on other threads, there are reasons to >> believe that there are problems with the threading libraries, but >> currently we don't have enough information to investigate them. Note >> that the other recent thread refers to problems running in the >> configuration you have just installed: see >> http://bugs.mysql.com/bug.php?id=12251 for more details. If you see >> anything similar, please let us know. >> > > > After doing alot of testing and trying this is some more new information: > > It actually DO crash on i386 FreeBSD 6.0-RC1 aswell, but very seldom > (around once every 4-5th hour, this time we get a Signal 10 instead, see > below). The errors are reproducable for MySQL 4.1.15 and MySQL 5.0.15 so > the problem still exists on 5.0.15. Of course we have tried on different > machines aswell to make sure it's not hardware related. On a FreeBSD > 5.3 machine Mysql 4.1.15 works fine. > > > mysqld got signal 10; > This could be because you hit a bug. It is also possible that this binary > or one of the libraries it was linked against is corrupt, improperly built, > or misconfigured. This error can also be caused by malfunctioning hardware. > We will try our best to scrape up some info that will hopefully help > diagnose > the problem, but since we have already crashed, something is definitely > wrong > and this may fail. > > key_buffer_size=1048576 > read_buffer_size=131072 > max_used_connections=99 > max_connections=400 > threads_connected=44 > It is possible that mysqld could use up to > key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections > = 461820 K > bytes of memory > Hope that's ok; if not, decrease some variables in the equation. Adding to this, using the following in libmap.conf fixes the problems: libpthread.so libthr.so libpthread.so.1 libthr.so.2 libpthread.so.2 libthr.so.2
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