Date: Fri, 15 Nov 2024 17:30:09 +0100
From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Andy Fan <zhihuifan1213@163.com>
Cc: David Rowley <dgrowleyml@gmail.com>, 
	Peter Eisentraut <peter@eisentraut.org>, Amit Langote <amitlangote09@gmail.com>, 
	Alvaro Herrera <alvherre@alvh.no-ip.org>, jian he <jian.universality@gmail.com>, 
	Chapman Flack <chap@anastigmatix.net>, pgsql-hackers@lists.postgresql.org
Subject: Re: Extract numeric filed in JSONB more effectively
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> On Thu, Sep 12, 2024 at 03:03:18AM GMT, Andy Fan wrote:
>
> > I imagined you'd the patch should create a SupportRequestSimplify
> > support function for jsonb_numeric() that checks if the input
> > expression is an OpExpr with funcid of jsonb_object_field().  All you
> > do then is ditch the cast and change the OpExpr to call a new function
> > named jsonb_object_field_numeric() which returns the val.numeric
> > directly.  Likely the same support function could handle jsonb casts
> > to other types too, in which case you'd just call some other function,
> > e.g jsonb_object_field_timestamp() or jsonb_object_field_boolean().
>
> Basically yes. The reason complexity comes when we many operators we
> want to optimize AND my patch I want to reduce the number of function
> created.
>
> The optimized functions and operators includes:
> 1. jsonb_object_field / ->
> 2. jsonb_array_element / ->
> 3. jsonb_extract_path / #>
> 4. jsonb_path_query
> 5. jsonb_path_query_first
>
>
> > ..., in which case you'd just call some other function,
> > e.g jsonb_object_field_timestamp() or jsonb_object_field_boolean().
>
> This works, but We need to create 2 functions for each operator. In the
> patched case, we have 5 operators, so we need to create 10 functions.
>
> op[1,2,3,4,5]_bool
> op[1,2,3,4,5]_numeric.
>
> Within the start / finish function, we need to create *7* functions.

Any particular reason you want to keep number of functions minimal? Is
it just to make the patch smaller? I might be missing something without
looking at the implementation in details, but the difference between 10
and 7 functions doesn't seem to be significant.