Client Case Study.....1

One Large Pool.....60,000 Buffers
We don’t have any Performance Problems....
- Nobody is Complaining about Poor Performance...
- Our BufferPool Performance is Great!!!
Reality...
- Getpage/RIO averaged between 50 -70:1
- Actual HIT RATIO averaged between 45 - 55%!!!! POOOOR!!!
Overall, Transactions Averaged > than 1 Second of Class 2 Elapsed
The average I/O Wait per Transaction was between .4 - .5 Seconds
- This alone should indicate a problem.....

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Notes:

I often hear people say that their DB2 system doesn’t have any performance problems. Well, I have never seen one that didn’t, and I firmly believe that every system has performance problems. Of course the critical factor is the ‘magnitude’ of the problems, and the effort required to correct them. Sometimes (but rarely) the problems are not significant, while the effort will be very large...therefore they might not be worth fixing.

When somebody says they don’t have any DB2 performance problems, they either don’t know where or how to look for them, or simply haven’t taken the time to look.

Any installation using only one pool, and thinking they have good and efficient performance, really hasn’t gotten the message. Why do you think IBM gave us 60 Pools??

These are initial performance results from one installation...before tuning...that said they had good performance.

Just because nobody complains, this does not mean things are running well.....