thanks for the reply. i was told that it is possible that the process used to create the table uses a large amount of space in the TS-A tabelspace for temporary work by database behind the scene. It did not use the temporary space in temporary tablespace TS-B though. Is this true? what are the temporary works needed in a "create as select" statement? and why in such a statement, the process use the tablespace where the table will be created to do the temporary work instead of in the temporary tablespace?
thanks.