Poor hash Join performance

From: <cshelt_at_acxiom.com>
Date: Fri, 26 Jan 2001 20:38:11 GMT
Message-ID: <94sn7j$cf3$1@nnrp1.deja.com>

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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http://www.deja.com/ Received on Fri Jan 26 2001 - 14:38:11 CST