On 15 February 2017 at 12:52, Robert Haas <robertmh...@gmail.com> wrote: > Personally, I find it somewhere in the middle: I think the way it > works now is reasonable, and I think what he wants would have been > reasonable as well. However, I find it hard to believe it would be > worth changing now on backward compatibility grounds.
Honestly I was quite surprised to discover that sum(float4) worked this way because I assumed it followed the same pattern as integers. But I wonder what you mean by backward compatibility grounds. If sum(float4) returned a float8 the only compatibility issue would be someone who did "create table as" and then expected to get a float4 column and instead got a float8 column. That seems like a much more minor corner case than most any other backward incompatible change in any release. Moreover, it wouldn't be hard to make sum(float4) use a float8 as an accumulator and then cast to float4 for the final state. That would be 100% compatible with the existing behaviour aside from producing more accurate results. (Though as an aside, I think Konstantin would be much better served by using integers and storing cents or whatever unit of currency is small enough. That would actually result in accurate results which neither float4 nor float8 guarantee.) -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
