It is possible that you run a DSS type report every once
in a while and that would bring the read cache rate down.

HTH,
Zev Berezin
Database Administrator
B&H Photo - www.bhphoto.com

From: "Davorin Kremenjas" <davorin.kremenjas@srce.hr>
To: informix-list@iiug.org
Subject: Sudden drop in read cache rate - why?
Date sent: Thu, 30 Jun 2005 13:36:06 +0200
Organization: CARNet, CROATIA
Send reply to: "Davorin Kremenjas" <davorin.kremenjas@srce.hr>

> Hello everyone.
> I'm experiencing Informix behaviour that feels weird to me.
> Sometimes, let's say once a week on average, read cache rate drops suddenly.
> Most of the time read cache rate is very high, around 99.7 percent. And all
> of the sudden it drops to somewhere around 50%.
> Then it spends few hours reaching 95% and a day or two to get over 99%
> level. As you've already guessed, after few more days the story repeats
> itself.
> It never happens with write cache rate, though.
> I never experience buffer overflow, that is "onstat -p" reports ovbuff to be
> zero, so I guess I have enough buffers configured.
>
> Config is: IDS 9.40UC5W2 on Solaris 9, Sun Fire V480 with 2 processors and 4
> GB RAM.
>
> Thanks everyone.
>
>
>


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