Re: Poor hash Join performance

In article <94sn7j$cf3$1_at_nnrp1.deja.com>,   cshelt_at_acxiom.com wrote:
> Hi all-
>
> I am extracting from and Oracle DB that is not running parallel
> server. I've noticed that Merge/Sort Joins are running at fair speeds
> while Hash joins are running insanely slow (1.5 million table and 2.5
> million table was going to take around 60 hours for hash and 1 hour
 for
> Merge). Here are some of the parameters
>
> Hash_Area_Size =20 meg
> Sort_Area_Size = 10 meg
> Hash_Multiblock_IO_count = 16 db_file_multiblock_read_count = 32
> db_block_size = 16k
>
> Is there anything else that might cause such a large difference in
> performance?
>
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You might want to include the platform, OS, size of the box, drives, etc.

Also are the tables indexed and how big is a row in the table(s)?

--
Michael Krolewski
Rosetta Inpharmatics
mkrolewski_at_rii.com
              Usual disclaimers


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