Slow query, can't see why - 06-22-2012 , 04:06 PM
I have a query hat does :
DELETE FROM TABLE_A WHERE ID NOT IN (SELECT ID FROM TABLE_B)
and it's taking ages to run (it's not finished yet after 20 minutes)
TABLE_A has 64,000 rows
TABLE_B has 13 rows
So I would assume Oracle would compare each of the 64,000 rows in TABLE_A,
to 13 values it stored in memory, and that should happen in a flash. I mean,
64k rows is nothing.
The plan does a full table scan on both tables, which is normal, and the
query is 95% CPU and this machine is normally pretty fast.
Can anyone comment ? I may be missing something obvious.
Re: Slow query, can't see why - 06-22-2012 , 06:33 PM
On Jun 22, 2:06*pm, "Syltrem" <syltremz... (AT) videotron (DOT) ca> wrote:
@home.com is bogus.
Re: Slow query, can't see why - 06-22-2012 , 08:51 PM
"joel garry" <joel-garry (AT) home (DOT) com> wrote
On Jun 22, 2:06 pm, "Syltrem" <syltremz... (AT) videotron (DOT) ca> wrote:
I rephrased it and it ran in a few seconds :
delete from TABLE_A A
where not exists (select 1
from TABLE_B B
where B.id = A.id )
Thanks for replying and have a good night, if night it is in your part of
the world !
Re: Slow query, can't see why - 06-24-2012 , 11:58 AM