Kevin Grittner wrote:
> David Rowley <[email protected]> wrote:
> > 5. Dependant Aggregates
>
> > Item 5 makes items 1-4 a bit more complex as with this item
> > there's opportunity for very good performance improvements by
> > allowing aggregates like AVG(x) also perform all the required
> > work to allow SUM(x) and COUNT(x) to be calculated for "free" in
> > a query containing all 3 aggregates.
>
> Not only CPU is saved, but the optimizations for materialized views
> would require the aggregate function's transition state to be saved
> in each row, and the duplicate state information among these
> functions would be a waste of space.
Uh, this also requires serialization and deserialization of non-
finalized transition state, no?
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Álvaro Herrera http://www.2ndQuadrant.com/
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