Hello, .. > up front, I'm not a database expert by any means and I'm nowhere close > to an Oracle expert, or even an Oracle novice. If Oracle was a > swimming pool, I would have those little floaty duck things on my > arms. Please go through this link http://asktom.oracle.com/pls/asktom/f?p=100:11:0::NO::P11_QUESTION_ID:15695764787749 Going through this and other queries/replies from Tom helps much more than going through Oracle documentation. Tom is far more helpful than the floaty ducks. By the way, I have used MVs in Oracle for a long time and did not run into major issues with them. But I started working with Oracle sometime ago. So what comes across as 'strange' SQL to non-Oracle users is 'very normal' SQL for me:). Do be careful with on COMMIT FAST REFRESH MVs in OLTP systems.
" 4) basically, your commits will tend to serialize. Whether this is an issue depends on how long your materialized view takes to refresh itself. Remember - the commits will serialize - not entire transactions, just the very end of them. "
"As mentioned above, materialized views typically add overhead to individual transactions and, if created with REFRESH ON COMMIT, will introduce contention. The overhead arises from the need to track the changes made by a transaction, these changes will either be maintained in the session state or in log tables. In a high end OLTP system, this overhead is not desirable. "
Regards, Jayadevan
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