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From: gnb@bby.oz.au (Gregory N. Bond)
Newsgroups: comp.databases
Subject: Re: Is there a "hot" DB machine for INGRES?
Message-ID: <1990Nov15.235628.10040@melba.bby.oz.au>
Date: 15 Nov 90 23:56:28 GMT
References: <747@icni.UUCP> <46494@sequent.UUCP>
Sender: news@melba.bby.oz.au
Organization: Burdett, Buckeridge and Young Ltd.
Lines: 36
In-Reply-To: lugnut@sequent.UUCP's message of 14 Nov 90 22:28:47 GMT

>>>>> On 14 Nov 90 22:28:47 GMT, lugnut@sequent.UUCP (Don Bolton) said:

Don> Though my employer would have a vested interest in my statements here,
Don> I speak for my own perspective...

Don> The multi processor "box" as you call it will benifit you in user
Don> throughput, even if your RDBMS has not been optimized for paralell
Don> processing.

Only if you have enough active users that there are more than one db
task active for most of the time.  That is surprisingly rare!

Our situation, even though we had plenty of users, was that the
wallclock time for each operation was too high, and that it was
extremely rare to have two different backends active at once (we use
Ingres 5, with a backend per process).  So a sequent-style machine was
not a good choice for us.  We bought a single CPU Solbourne 5/600,
which had much better wallclock time for a single user, as well as
handling more users faster than our old server (a Sun 3/260).

A Wild Ass Guess would seem to indicate that 20 or more users running
applications more or less normally would be required before there was
a sufficient number of distinct backends in the run queue for a
multi-cpu to be a gain, at least with normal sorts of enquire/update
applications. 

This sort of assumes a dedicated DB machine. If you were running front
ends, X, logins, compiles or other compute-intensive stuff on the same
machine, then the multi-cpu will become attractive much sooner.  And
the Solbourne can take up to 8 processors if that is ever a problem.

Greg.
--
Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia
Internet: gnb@melba.bby.oz.au    non-MX: gnb%melba.bby.oz@uunet.uu.net
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