query and delete records really slow in a table

From: LegeDoos <legedoos_at_gmail.com>
Date: Fri, 19 Oct 2007 14:28:32 +0200
Message-ID: <8d3d6eb70710190528t2d3bedc7sd8b101a64b71f322@mail.gmail.com>

Hi there!

We have a couple (18) of tables "linked" with foreign keys and cascading delete. The largest table contains < 1.000.000 records.

When deleting a record from the top level table, this is extremely slow (like waiting a couple of minutes). On another database (on the same server and on another server) deleting is fast (<1sec). Tables contain defferent data.

-There are no blocking locks
-rebuilding the indexes didn't help
-the explain plan looks ok and is the same for the different databases

0		DELETE STATEMENT optimizer=ALL_ROWS (cost=460 card=1 bytes=73)	
1	0	  DELETE of 'OST_STUDENT_STUDIEVOORTGANG'	
2	1	    HASH JOIN (SEMI) (cost=460 card=1 bytes=73)	
3	2	      TABLE ACCESS (FULL) of 'OST_STUDENT_STUDIEVOORTGANG' TABLE
(cost=57 card=31859 bytes=1146924)
4	2	      TABLE ACCESS (FULL) of 'OST_STUDENT_EXAMEN' TABLE (cost=199

card=55431 bytes=2050947)

-I moved all tables en indexes to another tablespace, didn't help
-There are no errors in the alert.log.

Can anybody help?

Thanks!

Rob
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http://www.freelists.org/webpage/oracle-l Received on Fri Oct 19 2007 - 07:28:32 CDT