| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Josh Berkus <josh(at)agliodbs(dot)com>, Tim Dudgeon <tdudgeon(dot)ml(at)gmail(dot)com>, pgsql-sql(at)postgresql(dot)org, postgres performance list <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: [PERFORM] Re: querying with index on jsonb slower than standard column. Why? |
| Date: | 2014-12-12 22:10:29 |
| Message-ID: | CAGTBQpZDYYF+UYgFQrKUutGk1pHJ2i0m7DS8sgte0GyZf7A8tg@mail.gmail.com |
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| Lists: | pgsql-performance pgsql-sql |
On Fri, Dec 12, 2014 at 6:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> The usability issue could be fixed by teaching the planner to fold a
> construct like (jsonb ->> 'foo')::numeric into (jsonb ->># 'foo').
> But I'm not sure how we do that except in a really ugly and ad-hoc
> fashion.
It would be doable if you could have polymorphism on return type, and
teach the planner to interpret (jsonb ->> 'foo')::numeric as the
operator with a numeric return type.
That's a trickier business even, but it could be far more useful and
generically helpful than ->>#.
Tricky part is what to do when the cast is missing.
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