Re: Rounding to even for numeric data type

Dean Rasheed wrote, On 2015-03-28 10:01:
> On 28 March 2015 at 05:16, Andrew Gierth <andrew@tao11.riddles.org.uk> wrote:
>>>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
>>
>>  Tom> I think the concern over backwards compatibility here is probably
>>  Tom> overblown; but if we're sufficiently worried about it, a possible
>>  Tom> compromise is to invent a numeric_rounding_mode GUC, so that
>>  Tom> people could get back the old behavior if they really care.
>>
>> I only see one issue with this, but it's a nasty one: do we really want
>> to make all numeric operations that might do rounding stable rather than
>> immutable?
>>
> 
> Yeah, making all numeric functions non-immutable seems like a really bad idea.

Would it be possible to make it an unchangeable per-cluster or
per-database setting, kinda like how encoding behaves? Wouldn't that
allow to keep the functions immutable?