[comp.databases] MP servers

dhepner@hpisod2.HP.COM (Dan Hepner) (11/18/89)

From: forrest@phobos.sybase.com (Jon Forrest)
>>> 
>>> One of the strong points of the Sybase architecture is that we
>>> require only one operating system process per Server.
>>
>>Could you comment on if or how this model affects Sybase's
>>ability to exploit multiple processor architectures?
>
>Instead of replying to this perfectly reasonable question, I'll
>defer to descriptions you'll see in the future about our MP product.

Maybe you could discuss the abstract question, without offering
any claims about any Sybase product.

It would seem to the naive that in an MP system, assuming that
performance was limited by the CPU cycles available to the server,
that you would want your server to consist of at least one OS process 
per processor.

Are there alternatives?

Dan Hepner

forrest@phobos.sybase.com (Jon Forrest) (11/20/89)

In article <13520003@hpisod2.HP.COM> dhepner@hpisod2.HP.COM (Dan Hepner) writes:
>
>Maybe you could discuss the abstract question, without offering
>any claims about any Sybase product.
>

The other reason why I can't comment on matters relating to the
MP server is because I don't know anything about it, or at least
not enought to present even the relevant abstract questions
intelligently. Unhappily, you'll have to wait for someone else
from Sybase to respond or you'll have to wait for more general information
to appear from Sybase. Sorry.

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

Jon Forrest WB6EDM
forrest@sybase.com
{pacbell,sun,{uunet,ucbvax}!mtxinu}!sybase!forrest
415-596-3422

harrism@aquila.DG.COM (Mike Harris) (11/28/89)

In article <7141@sybase.sybase.com>, forrest@phobos.sybase.com (Jon Forrest) writes:
> 
> In article <13520003@hpisod2.HP.COM> dhepner@hpisod2.HP.COM (Dan Hepner) writes:
> >
> >Maybe you could discuss the abstract question, without offering
> >any claims about any Sybase product.
> >
> 
First, my input to your MP question:

First, It is VERY advantageous to have a server per processor. That way
time can be allocated against your workload, concurrently, by both processors.
The overhead involved (not insignificant) is more than made up by the extra
cycles that your workload receives. And also by the scalability the product
(to >2 MPs, tuning, etc). Also, it is advantageous to have multiple servers
even on a singe processor for another reason: That being I/O. Unless a
server is very smart (Sybase does have os hooks to take advantage of this
in some circumstances where available in the os platform) it will be hung
when it  performs I/O,  or verrrrry long queries. Even with disk caching
and async I/O, pended writes are still required during the commit phase.

> The other reason why I can't comment on matters relating to the
> MP server is because I don't know anything about it, or at least
> not enought to present even the relevant abstract questions
> intelligently. Unhappily, you'll have to wait for someone else
> from Sybase to respond or you'll have to wait for more general information
> to appear from Sybase. Sorry.

I now understand the reasoning, or lack thereof, in Jons previous discussions.
I'm sorry, but I don't see how one can reasonably discuss the merits of even
a single server architecture without understanding the basics of multiple
server architectures. Especially considering the fact that their product
has a notion of "threads". The problems & challenges are very similar in
nature.

I do respect him for finally admitting it. This is a forum for discussion.
Let's ask questions & learn answers - not act like experts where we aren't.
> 
> ----
> Anything you read here is my opinion and in no way represents Sybase, Inc.
> 
Unfortunately, most people forget about this line - esp  when the person
is arguing the merits of their companies product on a forum such as 
comp.databases.

regards,

Mike Harris - KM4UL                      harrism@dg-rtp.dg.com
Data General Corporation                 {world}!mcnc!rti!dg-rtp!harrism
Research Triangle Park, NC