RE: optimize hash join between 2 large tables

  • From: "Christian Antognini" <Christian.Antognini@xxxxxxxxxxxx>
  • To: <Paula_Stankus@xxxxxxxxxxxxxxx>
  • Date: Fri, 21 Jan 2005 16:28:08 +0100

Hi Paula

>Other then use sort_area_size to sort in memory and parallel query what
>can be done to optimize a pull of 2 large tables joined together where
>most of the rows from both tables are selected???

First of all a hash join use the memory that is configured via =
hash_area_size and not sort_area_size.

A possibility to further speed up joins (in addition to memory and PX) =
is to use partition-wise joins. In the tuning guide you find information =
about it. Notice that to take out the max, the execution of a =
partition-wise join should be parallelized.


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