How to optimize DELETE for large number of data?

Hi Guys,
I am creating a DELETE sql for deleting large amount of data, approximately a million records. When I tested it, it got a lot amount of execution time. Is there a way how can I optimize this query?
I highly appreciate any idea from you guys!
Thanks,
Jay

JayPavia wrote:
I am creating a DELETE sql for deleting large amount of data, approximately a million records. When I tested it, it got a lot amount of execution time. Is there a way how can I optimize this query?
I highly appreciate any idea from you guys!Jay,
one quite nice approach is described in the AskTom thread: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:2345591157689#2356959585102
In a nutshell: You can create a partitioned table with the same layout (using e.g. a RANGE partitioning with a single default partition), insert the remaining data into that table and swap the two segments using ALTER TABLE EXCHANGE PARTITION.
This allows you to load the data into the partitioned table using all means available to you, e.g. direct-path parallel insert with nologging attribute of the table to make it as fast as possible, rebuilding/creating any indexes in bulk after the load completed.
Furthermore, at least seamless read-access to the table is possible while you're performing this operation, and you don't have to deal with renaming/granting etc. which you would need to do with a traditional CTAS approach.
Of course, if the table needs to be online for DML while performing the DELETE you can't use these options.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/

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