Hi,
I am converting a non-partitioned table to Partitioned(range or Ref). For test scenario, I have a table with 50 GB data (300 million rows) and 100 GB CLOB column data. I tested below options and timings are not as per my satisfaction level.
1. Create Table As Select -- Took 8 hrs
2. DBMS_REDIFINITION -- Took 6 hrs
3. Create Table As Select without CLOB column -- 15 min
4. Create Table as Select with Empty CLOB (hardcoded) -- 2 hrs 15 min
5. Alter table swap partition NoValidate -- Less than a minute, however data sits in wrong partition.
6. Export/Import -- I lost timings
7. Just delete -- 100 million in 2 hrs.

For 100GB CLOB, if it takes 6 hrs, then 3 TB will take considerable amount of time and online and batch cannot be stopped for this activity.

My expectation is that going forward, I will able to maintain table growth. However if I need to spend sometime for one time activity I have only 8 hrs of window to perform one task. I can split into multiple tasks if needed, but application should able to work after that window. Basically chunking of task should not impact Online/Batch if I am out of window.

Thanks
Singh

create table t as 
  select level x, 'stuff' y from dual
  connect by level <= 1000;

select count(*) from user_tab_partitions
where  table_name = 'T';

COUNT(*)   
         0
  
alter table t modify
  partition by hash (x) partitions 2 online ;
  
select count(*) from user_tab_partitions
where  table_name = 'T';

COUNT(*)   
         2