| Pleaze help with slow query [message #375200] |
Fri, 03 August 2001 09:46  |
Nina
Messages: 113
Registered: March 2000
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Senior Member |
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This query is causeing our application to run very slow. The tables have been analyzed, explain plan ran, etc Any tips?
select distinct tableA_id, tableA_numb, tableA_last_name, tableA_first_name,
tableB_phone_area||tableB_phone_number
from tableA, tableB
where
tableA_numb = tableB_numb
and tableA_change_ind is null
and tableB_phone_area||tableB_phone_number = '123'
and tableB_status_ind is null;
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| Re: Pleaze help with slow query [message #375204 is a reply to message #375200] |
Fri, 03 August 2001 17:02  |
joli
Messages: 5
Registered: August 2001
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Junior Member |
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Hi Nina,
bad performance may be resulting from full table
scans caused by the two IS NULL clauses. Also
the string concatenation on the phone column
values may cause full table scans. Depending on
your index profile ... and ...area = '1' and
...number='23' may boost. If change_ind and
status_ind have low cardinality a bitmap index
might help.
Just rough guesses, so far ...
Cheers, Joli
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