So I created the tables, populated 0. All rights reserved. Is there some other reason you prefer your form of the statement? October 26, - pm UTC.
Very helpful info here! I'm a newbie and I got more than I bargined for here. However it did help be learn a little about performance tuning - which I'll have to do in my new job -- and the many ways it can be done.
Also, the saying is true -- don't shoot a gifthorse in the mouth! November 14, - am UTC. Alexander the ok, November 14, - pm UTC. Tom a couple of posts up you pointed out that Colin's comparison was flawed because of the recently touched blocks being in cache on the 2nd pass. How do you usually avoid this for fair tests? Run the first twice? An insert maybe run into constraints problems in that case.
November 15, - am UTC. Your example showed two queries: the unsorted with LIOs, and sorted with I am not arguing sqlplus lio count is "highly summarized" this would happen with or without sqlplus, for all clients. See my notes here on update tuning.
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Just e-mail: and include the URL for the page. All rights reserved by Burleson. Oracle removes index entries without re-balancing the index tree a "logical delete" , but this is still time-consuming, especially if you have lots of indexes on the target table.
Also note that you can rebuild the dropped indexes nologging mode. Instead of select for update , savvy Oracle developers will adopt alternatives mechanisms like a re-read upon update commit where the transaction re-read the rows and ensure that it has not changed since the original read. Have a small, separate data cache for high DML tables As more people adopt bit servers with giant data buffers, we see a delay caused by the database writer process having to scan through giant data buffers seeking dirty blocks.
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