Re: Move table online and update the indexes at the same time.
- From: Tanel Põder <tanel.poder.003@xxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 27 Jul 2004 01:36:59 +0300
> Tanel,
> Thanks for the reply.
> It's 9i. I thought about table redefinition but I am not sure how it
> affect the performance. Second, I wonder if there a need to get a lock on
> the table just for a split of a second. We do not have any chance locking
> the table since there are always several transactions using it.
> What is your experience? Since it appeared only in 9i I am a bit worried
> about using it.
I've never used it in production myself, but as much I've heard, it does
have its problems and limitations - thus extensive testing would be needed.
It will increase your load, since it basically creates a materialized view
log for your table (and you have to clone the table manually + build the
indexes + apply the changes incrementally later on).
Redefinition package will require a lock for short time on your table if
used properly. The temporary locking could be implemented by deferring your
transactions for a short time if possible and/or having a tight pl/sql loop
which retries the operation until it succeeds.
Btw, in 10g there is a "ddl_wait_for_locks" parameter which you can set to
true on your session level - that way Oracle will execute DDL commands in
wait mode, thus waiting until all incompatible locks on given object are
released, instead of erroring out immediately.
Btw, why are you trying to move your tables?
Tanel.
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