Re: Recommendations for QQRYDEGREE

Hello Rob,

Am 10.02.2020 um 16:37 schrieb Rob Berendt <rob@xxxxxxxxx>:

Some people are rather adamant about turning off QPFRADJ. The query optimizer will reoptimize a query if your memory size changes. IDK if there's a pad in there to say "if the memory size changes by a certain amount". Reoptimization can add some overhead.

This could make sense if the machine is only running SQL and nearly nothing else. Not a likely scenario, though.

On the other hand, there's always the possibility to change the QPFRADJ interval to the longest time possible: You don't want to shift memory around because (for example!) just one rarely occuring print job coming in generates excess paging in QSPL. The job will be done soon and there's no need to overly adjust, because printing is a minor thing.

Assuming new SQL queries coming in frequently from different jobs and workloads, thereby overwriting old queries in a cache, I don't think reoptimisation is a big issue in a real-world scenario.

:wq! PoC

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