Classic priority inversion. Back in the day we debugged a problem like
this in OS/2 2.x multi-processor. One solution was when a higher
priority thread tried to obtain a resource, if a lower priority thread
held it then the lower priority thread had its priority increased to
that of the blocked thread while it held the resource. Of course there
were more details than that, I don't remember what was finally
implemented.

-----Original Message-----
From: Firebird-Architect@yahoogroups.com
[mailto:Firebird-Architect@yahoogroups.com] On Behalf Of Ann W. Harrison
Sent: Tuesday, June 14, 2005 6:06 PM
To: Firebird-Architect@yahoogroups.com
Subject: Re: [Firebird-Architect] Can we, can we, can we????...

Arno Brinkman wrote:

>
> Shot in the dark:
> Also is there a way to switch priority for running requests?

My stock answer, coined in 1987, is that lowering the priority of a
request tends to slow down the entire system because the lower priority
request can't respond to blocking signals (or the SuperServer
equivalent) and so all the higher priority requests end up waiting for
it to release pages.


Regards,


Ann




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