Oracle Database Discussions

Hello experts.

I am running Oracle 11.2 and saw in OEM that I have a table that is candidate for shrinking space.
According to OEM, I can gain 5G by shrinking the table.
The table is 16G, so if I shrink the table, then it should reduce to approx. 11G, right?
This table is the primary table used by our application, so impact to production is very important.

Okay, so I'm wondering what the impact to production is on the table while I shrink the space on the table.
I am testing it now in my test environment.
First, I found I had a function based index which has to be dropped before I can shrink the table.
So I ran dbms_metadata to get the syntax to recreate the FBI, then dropped the FBI.

Next, i ran alter table owner.tablename enable row movement;
Then, I ran alter table owner.tablename shrink space cascade;

While I am running the shrink table command, I opened another session and I queried the table and even did updates on the table.
I was quite surprised in that the table is not locked and is still accessible for update and select statements.
In fact, I do not see any noticeable impact by the shrink table command.
Obviously, I am not in the production environment with hundreds of concurrent users, but my question is what kind of impact should I expect to see if I do this in production with people hitting this table? (No, this is not an IOT.)

Any ideas?

Edited by: 974632 on Feb 19, 2013 5:54 AM

NOTE: The table shrink command took: Elapsed: 00:43:17.19
Recreating the function based index took: Elapsed: 00:00:28.80