1 Always specify 4 digit version of Oracle (so 184.108.40.206, not '11g' or '11gR2)
2 always specify platform and version
3 what is the number of records and size in blocks of this table
4 what is the current definition of the column
5 can you run
create table <newtable> <correct definition> as select * from <oldtable>
rename <oldtable> to <something else>
rename <newtable> to <oldtable>
6 did you consider using dbms_redefinition?
Senior Oracle DBA
DDL commands update dictionary.
may be your dictionary is very big and has stale statistics.
you can consider this either
My db is in 220.127.116.11 on linux
Table has about 3milions of row.
I'm using DMU to change charset.
Before it perform:
ALTER TABLE MYTAB MODIFY (MYCOL VARCHAR2(280 byte));
ALTER TABLE MYTAB MODIFY (MYCOL VARCHAR2(100 CHAR));
Gather sys stats and fixed object stats doesn't resolve the problem.
Now i'm trying to gather application schema stats.
Have you identified which blocks (P1, P2 for the wait event) the 'db file sequential read' wait is on ?
Hemant K Chitale
doesn't understand? Did you try it?
i've tried gather sys stats but this not resolve the issue.
I abandoned the idea to use DMU.
I will use expdp/impdp.