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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Move table online and update the indexes at the same time.
> 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.
-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Mon Jul 26 2004 - 17:33:38 CDT
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