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From Bryan Pendleton <bryanwpendle...@gmail.com>
Subject Re: Derby Maintenance Activities
Date Wed, 10 Mar 2010 16:52:04 GMT
> Does anybody have experience of running statistics or compression which 
> they can share?

In my production Derby app, which has run 24x7 for over 4 years, I have
a few tables which I need to compress, approximately every 6 months.

I have not found it necessary to update statistics on my tables.

However, my tables are small and don't change very rapidly, which
is I think the primary reason that I don't need to compress them or
recompute their statistics very often.

I think that if you have highly volatile tables, the need for compression
and statistics is more substantial.

I think you should set up a mechanism to monitor the performance of your
most important transactions, and you should keep an eye on it, and you
should also periodically run SYSCS_DIAG.SYSCS_SPACE_TABLE, etc., and keep
an eye on those values, and, over time, you will probably develop an
intuition about what level of performance degration justifies doing a
statistics or compression pass.



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