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Message Posted: Mon, 12 Sep 2011 @ 07:26:09 GMT


     
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Subj:   Difference between types of join strategies
 
From:   sukul mahadik

Hi All

I need some help understanding the meaning of TYpe type of join strategies: Merge Joins and Hash joins Merge join is quite simple to understand. however i am not able to understand how hash join works and what are the circumstances under which optimizer will choose hash join.

Can any one please please hep me get answers to these questions?

- HOw does Hash Join work.

- When does optimizer choose hash join.

- Which one is better -->Merge or hash?

- Also in several hash joins i have seen word 'partitions'. Can you please help me understand what does that mean.


I believe this topic must have come up earlier as well.. If anybody has some good documentation over this then please forward .....


Thanks

Sukul



     
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