# Re: Statspack ratios help

*From*: "David Sharples" <davidsharples@xxxxxxxxx>*To*: bunjibry@xxxxxxxxx*Date*: Tue, 6 Jun 2006 20:49:36 +0100

well in theory yes but reality it can mean something entirely different. A 100% hit can mean that you are writing useless sql which floods the buffer cache with loads of blocks and then you are naturally going to hit in in the cahce next time round with another query

now to some people that would be nirvana, but the fact that you are doing thousands and thousands of LIO's per query passes them, you still have poor performacne even though the cache ratio is 100% (reason why you shouldnt rely on it being a good indicator).

Of course it could be the opposite and you have the best application in the world

Now in this case he says he is using hibernate to generate the sql, knowing a bit about hibernate and the number of io's his statspack report, i'm guessing it is a bit of a shocker

asktom explains this better than me obviously

On 06/06/06, Bryan Wells <bunjibry@xxxxxxxxx> wrote:

On 06/06/06, Bryan Wells <bunjibry@xxxxxxxxx> wrote:

As a Jr. wanting to be Sr. (someday) I have to ask the stupid questions:

why is Buffer % bad? Dont you want 100% buffer cache hit vs. 100% disk i/o?

**References**:**Statspack ratios help***From:*Sandeep Dubey

**Re: Statspack ratios help***From:*David Sharples

**Re: Statspack ratios help***From:*Bryan Wells

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