Re: Posix Shared Mem patch

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Josh Berkus <josh@agliodbs.com>

Cc: Robert Haas <robertmhaas@gmail.com>, Magnus Hagander <magnus@hagander.net>, Andres Freund <andres@2ndquadrant.com>, pgsql-hackers@postgresql.org, Thom Brown <thom@linux.com>

Date: 2012-06-29T17:48:53Z

Lists: pgsql-hackers

Josh Berkus <josh@agliodbs.com> writes:
>> If we could do that on *all* platforms, I might be for it, but we only
>> know how to get that number on some platforms. 

> I don't see what's wrong with using it where we can get it, and not
> using it where we can't.

Because then we still need to define, and document, a sensible behavior
on the machines where we can't get it.  And document that we do it two
different ways, and document which machines we do it which way on.

>> There's also the issue
>> of whether we really want to assume that the machine is dedicated to
>> Postgres, which IMO is an implicit assumption of any default that scales
>> itself to physical RAM.

> 10% isn't assuming dedicated.

Really?

			regards, tom lane