Ken You are right that exchange partition command should be dictionary updates, but there are few gotchas. Is that table regular heap table or any other special tables such as IOT, compressed tables etc? Are the table structures exactly same? Can you run this query for those two tables to see if there is any mismatch? select a.owner, a.table_name, a.column_name, b.column_name , a.data_type, b.data_type , a.data_precision, b.data_precision , a.data_length, b.data_length, a.nullable, b.nullable from dba_tab_columns a , dba_tab_columns b where a.owner=user and a.table_name=upper('T1') and b.owner=user and b.table_name=upper('T2') and a.column_name=b.column_name and ( a.data_type != b.data_type or a.data_precision!=b.data_precision or a.data_scale != b.data_scale or a.data_precision != b.data_precision or a.nullable != b.nullable ) / Also, could you turn on 10046 trace files before exchange partition command and send the trace file please? Thanks Riyaj "Re-yas" Shamsudeen ERP Financials DBA, New AT&T ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Naim Sent: Wednesday, March 12, 2008 7:35 PM To: oracle-l@xxxxxxxxxxxxx Subject: Partition exchange I am in the process of moving the partitions of a table from ASSM to a non-assm tablespace using the partition exchange method (create non partitioned table, indexes, constraints etc.). When I do the alter table exchange partition including indexes without validation command it runs for hours, doing a full table scan on all the partitions of the partitioned table which takes many hours. I understood that just the data dictionary is updated, and it should take a few seconds. Primary Wait event is db file scattered read. Can anyone shed some light on this phenomenon. DB version is 10.2.0.3 and is running on Solaris 10. Thanks, Ken