1.if we can use "alter TABLE <table_name> move tablespace <new_tablespace_name> " command online ?? Or should I ask for a downtime ?
2. I will move this table to a new tablespace and then will move the table back
to original tablespace. Can I do that ??? Will it help in reclaiming the space.
If yes then should I rebuild the indexes again...??
As I am going to do this in Production database so want to be careful.
1. You _can_ use it online, however, if your users are currently executing querys against the table when you execute the command, they will probable get ORA-08103. My suggestion to this is to plan a downtime for the operation.
2. Yes, you can move the table back and forth provided there's sufficient storage. However, it doesn't necessary help in reclaming space. If this the only object in the tablespace and its constraining you from doing so, then after you move it to a new tablespace, it will probably let you shrink down the tablespace. If the table is not empty (and I assume it is not), then you will need to rebuild the indexes afterwards.