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Stephan wrote:
> ======================================================
> The total story till now:
>
> Win2000
> 8.1.7.
>
> - I started having 1 instance called PREV
> - In PREV, I imported the PREVENT scheme containing about 30 tables
> - I analyzed (COMPUTE) the PREVENT scheme
> - I query from only 2 tables of that PREVENT-scheme (one -DISTRICT- having
> 20 records, the other -DISTRICT_STREET- 2000).
> - When I select from the PREV database by means of:
> "select id_district, district_name FROM district, district_street where
> (district_id=id_district) AND (place_street_id=707)"
>
> the performance is between 200msec and 2sec for generating 3 records (poor)!
>
> - In the PREV database I created a copy of the district table by means of:
> "create table district2 as select * from district"
> - I analyzed (COMPUTE) the PREVENT scheme again
> - When I select from the PREV database by means of:
> "select id_district, district_name FROM district2, district_street where
> (district_id=id_district) AND (place_street_id=707)"
> the performance is between 1msec and 10msec for generating the 3 records
> (good)!
> ==============================================
> So why is the performance using the imported table (20 records!) so bad?
> (does Oracle treat it different than the copy-table? conversion?)
>
>
> Please help...
> Stephan
>
From your post, it looks like the district and district2 tables are
identical. Since that's the case, it's probably not the table that's
causing the slowdown. What else enters into the picture? Well,
unfortunately, lots of things ... none of which we can guess from your
post. But here are some of the things to check (and by all means, do an
explain plan):