Re: Q: Estimated Cost from SET EXPLAIN?
Posted in 1995
George Follis (follis@esd.dl.nec.com) wrote:
<Stuff about the query and results of set explain - removed>
I will follow-up on some of the replies. And some other information
that may or may not make a difference.
The ESQL/C is 5.01. The Online Engine is 5.01. We are running UPDATE
STATISTICS on a regular basis (every hour). This is a hotel application
and they have massive updates and deletes all day long.
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There is a known problem with UPDATE STATISTICS for 5.0 Online, that
does cause some of the statistics to be set incorrectly. Check your
npused
column in systables... I'll bet it has a negative value. For some reason,
UPDATE STATISTICS doesn't work too well on tables that have massiveactivity of tons of inserts, then tons of deletes (Tons being a relative
term,
of course).
I have some Informix supplied documentation (not handy right now)
on a work-around for this problem. I'll try to email it to you when I
get my hands on it.
Paul Kapp
(Work) plk@usorder.com
(Play) PLKapp@aol.com