Thomas Kyte <tkyte_at_oracle.com> wrote in message news:<a62o0s02em0_at_drn.newsguy.com>...
> People just don't get it. Even when you show them -- they still don't believe
> you.
There is no need to believe you or anyone else. Everyone just should
do a few tests and find the thruth himself.
I've done it. I've tried to make out how number of extents impacts
performance while inserting and deleting data. I've runned tests for
several extent sizes from 8kB to 2MB, with both LMTs and DMTs.
Results: Up to thousand extents, everything is the same. No matter if
tablespace is DM or LM, nor if the extent size is 8kB or 2MB. After
this thousand border, situation has changed.
While using LMTs nothing has changed, but DMT has suffered negative
performance impact. For more than 8.000 extents, response time, while
inserting or deleting, has increased for about 1/6 of original value.
On DMT with lots of extents also dramatically increased time needed
for droping table, but that's not a critical value from productional
database's point of view.
Conclusion: LMTs are damn good thing while dealing with lots of
extents. Anyone who's using them, should take no care about number of
extents in his database and can start looking for something more
important (girls, beers, crappy SQL).
--
_________________________________________
Dusan Bolek, Ing.
Oracle team leader
Note: pagesflames_at_usa.net has been cancelled due to changes (maybe we
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email.
Received on Wed Mar 06 2002 - 09:19:47 CST
