Monday, July 29, 2013

Re: or-ing to QuerySets turns INNER into LEFT OUTER joins?

Hi Martin,

Am 2013-07-26 20:48, schrieb Martin J. Laubach:
> This is rather unusual. A join in the database should be quite a bit faster than
> doing things manually, except if the joined tables produce massive amounts of data. This
> suggests that you're missing useful indexes and/or statistics for your query.


Could you please elaborate a bit?

As I mentioned earlier, I'm no SQL/database expert. When I run the queries individually,
they're all reasonably fast, even though all of them have several thousand rows, and the
ERFASST table even has several millions. So I concluded that the proper indexes were
already in place.

I've also talked to our DB admins, who ran the full query through some Oracle
auto-optimizer tool, but said that it only suggested to add more indexes that, when
tried out, did not seem to buy anything.

Anything else that I should look into or steps to take?

Best regards,
Carsten



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