On Wed, 22 Sep 2004, Gaetano Mendola wrote:

> Now my question is why the 7.4 choose the hash join ?  :-(

It looks to me that the marge join is faster because there wasn't really 
anything to merge, it resulted in 0 rows. Maybe the hash join that is 
choosen in 7.4 would have been faster had there been a couple of result 
rows (just a guess).

It would be interesting to compare the plans in 7.4 with and without 
hash_join active and see what costs it estimates for a merge join compared 
to a hash join.

/Dennis Björklund

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