On Sat, Dec 13, 2014 at 12:05 AM, Andrew Dunstan <andrew@xxxxxxxxxxxx> wrote: > On 12/12/2014 08:20 PM, Tom Lane wrote: >> >> We can't just add the operator and worry about usability later; >> if we're thinking we might want to introduce such an automatic >> transformation, we have to be sure the new operator is defined in a >> way that allows the transformation to not change any semantics. >> What that means in this case is that if (jsonb ->> 'foo')::numeric >> would have succeeded, (jsonb ->># 'foo') has to succeed; which means >> it'd better be willing to attempt conversion of string values to >> numeric, not just throw an error on sight. >> >> > > > Well, I'm not 100% convinced about the magic transformation being a good > thing. > > Json numbers are distinct from strings, and part of the justification for > this is to extract a numeric datum from jsonb exactly as stored, on > performance grounds. So turning round now and making that turn a string into > a number if possible seems to me to be going in the wrong direction. It's still better than doing the conversion every time. The niceness of that implementation aside, I don't see how it can be considered the wrong direction. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
