Re: [SQL] querying with index on jsonb slower than standard column. Why?

On 08/12/2014 18:14, Adrian Klaver wrote:

Recheck Cond: ((((data ->> 'assay1_ic50'::text))::double precision > 90::double precision) AND (((data ->> 'assay2_ic50'::text))::double precision < 10::double precision))
> 
> which means we have to pull the JSONB value out of the tuple, search
> it to find the 'assay1_ic50' key, convert the associated value to text
> (which is not exactly cheap because *the value is stored as a numeric*),
> then reparse that text string into a float8, after which we can use
> float8gt.  And then probably do an equivalent amount of work on the way
> to making the other comparison.
> 
> So this says nothing much about the lossy-bitmap code, and a lot about
> how the JSONB code isn't very well optimized yet.  In particular, the
> decision not to provide an operator that could extract a numeric field
> without conversion to text is looking pretty bad here.

Yes, that bit seemed strange to me. As I understand the value is stored internally as numeric, but the only way to access it is as text and then cast back to numeric.
I *think* this is the only way to do it presently?

Tim