Re: Execution Plan: Infx 5.01
On Fri, 19 Jan 1996, Fred BON wrote:
> Hi,
>
> I used to work with database, but I'm new to Informix. Could you tell
> me how to obtain the execution plan of a request ? And, how to update
> the statistics of the index ? To perform this operation, is there another
> mean than drop and recreate the index ?
>
> TIA,
>
> Fred
> --
> -------------------------------------------------------------------
> Fred BON - Top Log Technologies
> Mail: fred@toplog.fr
> URL:<http://www.toplog.fr>;
> -------------------------------------------------------------------
Fred,
Get the faq (watch for Kerry Sainsbury's sig; it's there and elsewhere),
read the docs, but right now a few quick answers (maybe right this time).
update statistics; (updates statistics for all tables)
update statistics for mytable;
To see what's happening with your queries, and it's always advisable
to update statistics first, turn the optimizer on -
set explain on;
You'll begin to see the results of all your queries in the default output
file explain.out.
Dropping and recreating your indexes is a bit radical. If you're really
in the mood (and no one is going to be using the database), use
alter index to cluster (on the table name)
Not too sure about the syntax, but you can always get some help by doing
a Ctl-W in Informix's lean and mean front end, isql.
Yours,
Nick
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Nick Nobbe, Library of Congress
NLS/BPH
mail: nnob@loc.gov
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