Re: Buffer Management - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Buffer Management
Date
Msg-id 200206261711.g5QHBJM15565@candle.pha.pa.us
Whole thread Raw
In response to Re: Buffer Management  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Curt Sampson <cjs@cynic.net> writes:
> > Note that your proposal of using mmap to replace sysv shared memory
> > relies on the behaviour I've described too.
> 
> True, but I was not envisioning mapping an actual file --- at least
> on HPUX, the only way to generate an arbitrary-sized shared memory
> region is to use MAP_ANONYMOUS and not have the mmap'd area connected
> to any file at all.  It's not farfetched to think that this aspect
> of mmap might work differently from mapping pieces of actual files.
> 
> In practice of course we'd have to restrict use of any such
> implementation to platforms where mmap behaves reasonably ... according
> to our definition of "reasonably".

Yes, I am told mapping /dev/zero is the same as the anon map.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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