I have this formula to calculate bufferpool hit ratio:

DEC((1 - (FLOAT(TOTAL_DATA_PHYSICAL_READS) / FLOAT(TOTAL_DATA_LOGICAL_READS))) * 100,5,2)

Hypothetical question: is it possible, physical_reads could be greater than logical read resulting into negative hit ratio ?

Too much prefetching.

Yes,

Recently, I came across one database having Hit Ratio over 115 %.

But,

I wonder, do we need it to tune down ??



Regards
DBFinder

You may want to look at the unread prefetch pages metric. It may indicate that prefetching is too aggressive and you are reading more data from disk than you actually need, wasting I/O bandwidth.

That makes sense !!

Thanks

DBFinder