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From: forrest@phobos.sybase.com (Jon Forrest)
Newsgroups: comp.databases
Subject: Re: Client/Server processes and implementations
Keywords: Client Server Processes
Message-ID: <7185@sybase.sybase.com>
Date: 22 Nov 89 17:25:57 GMT
References: <7114@sybase.sybase.com> <6895@sybase.sybase.com> <2184@kodak.UUCP> <375@xyzzy.UUCP> <510@xyzzy.UUCP>
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In article <510@xyzzy.UUCP> harrism@aquila.DG.COM (Mike Harris) writes:
[a lot of good stuff about processes, servers, and CPU usage]

As I understand the issue, the main reason why we don't use multiple
processes is because of locking and synchronizations issues, and because
of the lack of portability inherent in any solutions to these problems.
We have no religious disagreements with using multiple processes.
But, first of all, by controlling locking and synchronization in
a portable single O.S. process environment, I think we can do a better
job than trying to understand the effects of each O.S.'s methods (if any)
of doing locking and synchronization. 

Don't forget that our limitiation is only that one database can't
be accessed by more than one server at a time. You can run any number
of servers on one machine, as long as you have the resources to support
the servers. Plus, given the fact that servers can talk to other servers
by  using RPC's, the end effect isn't that much different than having
multiple servers talking to the same database.

>Jon mentions (elsewhere in the net) a new MP architecture. Is Sybase working
>on this soley to take advantage of multiple processors? Wouldn't this
>architecture allow multiple servers on a single architecture?

I think as more MP servers come on the market from us and our competitors
there will be some discussion about just what constitutes a single server.
I also think this will be true for any kind of server that runs in
an MP environment, and not just a database server.
Other than this I have no comment about MP servers.

>
[a lot of good comments about dedicating resources to servers]

There's no doubt that people will use servers of various kinds on
machines that must perform other work. A dedicated machine for each
server is a ideal to strive for, but isn't always practical.
So, the performance of any server will deteriorate as a function
of what else is being done on the machine. When the server performance
become unacceptable either the competing work or the server itself
will get moved off to a different machine. This is normal and although
I grant that this might not be an axiom of client/server architecture
it is certainly a corolary.


----
Anything you read here is my opinion and in no way represents Sybase, Inc.

Jon Forrest WB6EDM
forrest@sybase.com
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