[RndTbl] mysql crash and non-restart due to RAM?

Trevor Cordes trevor at tecnopolis.ca
Mon Jan 4 12:54:13 CST 2016

On 2016-01-04 Hartmut W Sager wrote:
> I am surprised.  Doesn't a current high-grade OS like Linux (maybe not
> Windows) routinely close the gaps in RAM by relocating running code
> and data?  This is quite efficiently do-able in CPU architectures

I just read an article about this.  Supposedly modern linux (not sure
about RHEL6) does mem "defrag" only on oom condition (going from vague
memory).  Discussions always crop up about having a kthread that can do
periodic defrag outside of oom condition but I don't think this is
being done at present.

Defrag on oom does sound like what I just saw today, because when the
oom happened there was almost no contig ram left, but when I checked
the server a while later there were lots of bigger contigs, but still
not enough for a 4G alloc.

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