Re: Read ahead & Buffer wait ratio query.

Posted in 2001

Tham Huei Hwan — Fri, 19 Jan 2001 11:57:00 +0800 — source: Informix-list mailing list archive (1991-1998)

Hi all, Can anyone tell me what is the ideal percentage of RA for a well configure online instances from the formular provided by "Frank Langelage" "RApgused / (ixdaRA + idxRA + daRA) * 100" Thanks Frank Langelage wrote: > Tony Woods schrieb: > > > > Below is the formulla I use for calculating the Read Ahead usage : > > ((ixdaRA + idxRA + daRA) / RApgsused) * 100 > > Many I times I see the percentage is above 100. Does it mean that the page > > which was read ahead was read/used twice or more. > > No. Your formula is false. It must be "RApgused / (ixdaRA + idxRA + > daRA) * 100".