Re: jsonb and nested hstore

On 02/28/2014 02:00 PM, Tom Lane wrote:
> Peter Geoghegan <pg(at)heroku(dot)com> writes:
>> On Fri, Feb 28, 2014 at 5:01 AM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>>> But anyway, I think we've seen enough of these to conclude that the casts
>>> from hstore to jsonb and back should not be implicit. I am fairly confident
>>> that changing that would fix your complaint and the similar one that Peter
>>> Geoghegan had.
>> Yes, it will, but I think that that will create more problems than it
>> will solve (which is not to suggest that an implicit cast is the right
>> thing). That will require that any non-trivial usage of jsonb requires
>> copious casting, where nested hstore does not. The hstore module
>> hardly contains some nice extras that a minority of jsonb users will
>> be interested in. It contains among other basic things, operator
>> classes required to index jsonb. All of my examples will still not
>> work, plus a bunch of cases that currently do work reasonably well.
>> There'll just be a different error message.
> We should have learned by now that implicit casts are generally pretty
> dangerous things. I think putting in implicit casts as a band-aid for
> missing functionality is a horrid idea that we'll regret for a long
> time to come. I gather from upthread comments that the patch currently
> actually creates implicit casts in *both* directions? That's doubly
> horrid/dangerous.

I agree. I have removed them in my current tree.

>
> The more I read in this thread, the more I think that jsonb simply
> isn't ready. We should put it off to 9.5 so that we can have a
> complete implementation without so many rough edges. I'm afraid that
> if we ship it as-is, backwards compatibility considerations are going
> to prevent us from filing down the rough edges in future.
>
>

Well, the jsonb portion of this is arguably the most ready, certainly
it's had a lot more on-list review.

cheers

andrew