Re: MM deadlock [was: Re: arca-vm-8...]

Agus Budy Wuysang
1999-01-15T07:58:47Z

Andrea Arcangeli wrote:
>
> On Wed, 13 Jan 1999, Alan Cox wrote:
>
> > > >> Could somebody spare a minute to explain why is that so, and what
> > > >> needs to be done to make SHM swapping asynchronous?
> > >
> > > > Maybe because nobody care about shm? I think shm can wait for 2.3 to be
> > > > improved.
> > >
> > > "Nobody"? Oracle uses large shared memory regions for starters.
> >
> > All the big databases use large shared memory objects.
>
> I was't aware of that. I noticed that also postgres (a big database) uses
> shm but it's _only_ something like 1 Mbyte (at least during trivial
> usage). With my current code such 1 Mbyte would not be touched unless

Our current database size 1.6Gb, locks & buffers are
using "large" SHM heavily. Due to Linux SHMMAX = 16M,
allocation is divided into serveral 16M segments.

current database buffers = 130,000 * 1024 bytes
locks = 65536 * 18 bytes

Quick Spec:
Dual PPro 200MHz, 256Mb Ram
Kernel 2.2.0-pre6
Progress 7.3C08 via latest iBCS 2.1.x emulator

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