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goldminer 118 posts Joined 05/09
06 Oct 2014
Oracle vs Teradata Parallelism

Hello Everyone!
I have a couple of architects and developers telling me that Oracle is also a parallel database.  I fully understand the nature of Teradata's parallelism but do not know Oracle well enough to dispute this statement that Oracle is parallel as well.  Can anyone explain to me under what context they might be making this statement?  I understand there is a parallel hint in Oracle but surely that is not what they are talking about is it?

Raja_KT 1246 posts Joined 07/09
06 Oct 2014

Teradata's execution is parallel in terms of joins,aggregation,sorts..... How about other DBs? 
Oracle: The optimizer first calculates a serial execution plan for the SQL statement; if the estimated execution elapsed time is greater than PARALLEL_MIN_TIME_THRESHOLD , the statement becomes a candidate for automatic Degree of Parallelism.
hint is also one area, that shows the absence of parallelism. Parallel stmts need to be in queue?
I think you will come back with questions :)
I wish I can show practically ,when it comes to  a huge amount of data. For a very small amount of data, excel may outdo the rest :)

Raja K Thaw
My wiki:
Street Children suffer not by their fault. We can help them if we want.

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