Drop Command taking considerable time!!!

Question

Hi guys,
In the morning i had asked u alll about Truncate command taking time.
I used "Truncate <table> reuse storage" for truncating the table. It worked fine.
Now, when i'am dropping that same table due to some change in our plan, this is also taking considerable amount of time...
FYI,
The tablespace is Dictionary Managed Tablespace and the Oracle Version for this is 9.2.0.8.
Can somebody help...
Regards,
Nick.
Message was edited by:
Nick-- wud b DBA
Message was edited by:
Nick-- wud b DBA

Answer 1

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Hi
1. Note 68836.1 spells out a method to do this. Basically, it involves
a) truncate table reuse storage.
b) Then releasing extents slowly spreading it over many nights.
Night 1:
SQL> ALTER TABLE BIGTAB DEALLOCATE UNUSED KEEP 1707M; (2Gb*5/6)
Night 2:
SQL> ALTER TABLE BIGTAB DEALLOCATE UNUSED KEEP 1365M; (2Gb*4/6)
Night 3:
SQL> ALTER TABLE BIGTAB DEALLOCATE UNUSED KEEP 1024M; (2Gb*3/6)
But, you are out of luck. Since you have already started dropping the table, if you interrupt it, smon needs to cleanup. That might take longer time.
2. Another option, need to be planned better, is to convert Dictionary managed to locally managed tablespaces first and then drop the table. I never tested this method, but giving you an option.
dbms_space_admin.tablespace_migrate_to_local call can be used to convert from dictionary to locally managed tablespace.
Cheers
Riyaj
blog: http://orainternals.wordpress.com
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