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Read ahead & Buffer wait ratio query.

Posted in 2001

Topics: General Discussion

Tony Woods — — source: Informix-list mailing list archive (1991-1998)

Hello all, 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. I have seen this formulla in Informix list mails for calculating Buffer wait ratio or Buffer turnover ratio : ((bufwaits/(pagreads + bufwrits)) * 100) Can anybody please explain me the mean of this in simple english? Thanks a lot for all your replies. _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com

↪ replying to Tony Woods
Frank Langelage — — source: Informix-list mailing list archive (1991-1998)

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".

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