On Fri, 2007-10-26 at 16:37 -0400, Pablo Alcaraz wrote:
> Hi List!
> I executed 2 equivalents queries. The first one uses a union structure.
> The second uses a partitioned table. The tables are the same with 30
> millions of rows each one and the returned rows are the same.
> But the union query perform faster than the partitioned query.
I think you mean to use UNION ALL here. UNION forces a DISTINCT, which
results in a sort operation. What surprises me is that the UNION is
actually faster than the partitioning using inheritance.
I suspect it has something to do with the GROUP BYs, but we won't know
until you post EXPLAIN ANALYZE results.
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