Re: [2.4.17/18pre] VM and swap - it's really unusable

Stephan von Krawczynski
2002-01-07T14:34:21Z

On Sun, 6 Jan 2002 23:15:31 -0800
Petro <petro@auctionwatch.com> wrote:

> On Sat, Jan 05, 2002 at 04:44:05PM +0100, Stephan von Krawczynski wrote:
> > On Sat, 5 Jan 2002 01:24:42 -0800
> > Petro <petro@auctionwatch.com> wrote:
> >
> > > "We" (Auctionwatch.com) are experiencing problems that appear to be
> > > related to VM, I realize that this question was not directed at me:
> >
> > And how exactly do the problems look like?
>
> After some time, ranging from 1 to 48 hours, mysql quits in an
> unclean fashion (dies leaving tables improperly closed) with a dump
> in the mysql log file that looks like:

mysql question: is this a binary from some distro or self-compiled? If
self-compiled can you show your ./configure paras, please?

> Which the Mysql support team says appears to be memory corruption.
> Since this has happened on 4 different machines, and one of them had
> memtest86 run on it (coming up clean), they seem (witness Sasha's
> post) to think this may have something to do with the memory
> handling in the kernel.

There is a big difference between memory _corruption_ and a VM deficiency. No
app can cope with a _corruption_ and is perfectly allowed to core dump or exit
(or trash your disk). But this should not happen on allocation failures.

Unless all your RAM is from the same series I do not really believe in mem
corruption. I would try Martins small VM patch, as it looks like being a bit
more efficient in low mem conditions and this may well be the case you are
running into. This means 2.4.17 standard + patch.

Regards,
Stephan