Re: [PATCH] Negative Transition Aggregate Functions (WIP)

On 14/01/14 14:29, Tom Lane wrote:
[...]
> (2) the float and numeric variants should be implemented under 
> nondefault names (I'm thinking FAST_SUM(), but bikeshed away). People 
> who need extra speed and don't mind the slightly different results can 
> alter their queries to use these variants. One reason I'm thinking 
> this is that whatever we do to ameliorate the semantic issues is going 
> to slow down the forward transition function --- to no benefit unless 
> the aggregate is being used as a window function in a moving window. 
> So I'm less than convinced that we *should* implement any of these 
> designs in the default aggregates, even if we get to the point where 
> we arguably *could* do it with little risk of functional differences. 
> regards, tom lane 
How SUM_FAST() instead, then it will more likely to be close to SUM() in 
an index?


Cheers,
Gavin