Re: buffer hit cache ratio

> I'd argue that actually the BCHR *may* be more useful than many give credit
> for in this sense and this sense only.
>
> If for months your ratio hovers around the 80% mark and then it suddenly
> move significantly - say to 95% or to 655 - then *something* has changed and
> that may well be worth investigating. Note I don't say that you can tell
> whether the change is good or bad, or that one figure is *better* than
> another, just that your IO pattern has changed and it might be an idea to
> see why.

The is the one area where I've actually argued for using the BCHR in the past! If you were at one point for many months, and you are at a completely different point, then something has changed. Is this good or bad? No one can tell just by looking at the BCHR. Does this mean that database performance is worse or better? No one can tell just by looking at the BCHR.

Cheers,
Brian

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Brian Peasland
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