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

On Fri, Jan 10, 2014 at 2:07 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Florian Pflug <fgp(at)phlo(dot)org> writes:
>> On Jan10, 2014, at 19:08 , Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Although, having said that ... maybe "build your own aggregate" would
>>> be a reasonable suggestion for people who need this? I grant that
>>> it's going to be a minority requirement, maybe even a small minority
>>> requirement. People who have the chops to get this sort of thing right
>>> can probably manage a custom aggregate definition.
>
>> So we'd put a footgun into the hands of people who don't know what they're
>> doing, to be fired for performance's sake, and leave it to the people
>> who know what they are doing to put the safety on?
>
> If I may put words in Kevin's mouth, I think his point is that having
> float8 sum() at all is a foot-gun, and that's hard to deny. You need
> to know how to use it safely.

Yeah, but Florian's point is that not all foot-guns are created equal.
The fact that we're walking around with a loaded BB-gun in our hip
pocket is not a good reason to replace it with a howitzer.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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