plan for function returning table combined with condition

[Thierry Henrio <thierry.henrio@xxxxxxxxx>]

Hello,

I have a table with a jsonb row, opening_times, that I need to expand for later processing. jsonb is an object, like so {"1": [["06:00:00", "23:59:59"]], ...}.

select id, name, day::int, (value -> 0 ->> 0)::time as startt, (value -> 0 ->> 1)::time as endt from (
  select s.id, s.name, j.* from shops s cross join jsonb_each(s.opening_times) as j(day, value)
) t

I made a function out of this sql:

create or replace function expand_shop_opening_times() returns table(id int, name text, day int, startt time, endt time)

as $$

select id, name, day::int, (value -> 0 ->> 0)::time as startt, (value -> 0 ->> 1)::time as endt from (

  select s.id, s.name, j.* from shops s cross join jsonb_each(s.opening_times) as j(day, value)

) t
$$ language sql

So I can use it like so (A):

select id, name from expand_shop_opening_times() where id=1307;

The plan for statement (A) is:

 Function Scan on expand_shop_opening_times  (cost=0.25..12.75 rows=5 width=36) (actual time=15.950..16.418 rows=7 loops=1)
   Filter: (id = 1307)
   Rows Removed by Filter: 10540
 Planning Time: 0.082 ms
 Execution Time: 16.584 ms

Whereas plan for statement (B)

select id, name, day::int, (value -> 0 ->> 0)::time as startt, (value -> 0 ->> 1)::time as endt from (
  select s.id, s.name, j.* from shops s cross join jsonb_each(s.opening_times) as j(day, value)
) t
where id=1307

I have:

 Nested Loop  (cost=0.28..12.80 rows=100 width=41) (actual time=0.030..0.038 rows=7 loops=1)
   ->  Index Scan using shops_pkey on shops s  (cost=0.28..8.29 rows=1 width=341) (actual time=0.012..0.014 rows=1 loops=1)
         Index Cond: (id = 1307)
   ->  Function Scan on jsonb_each j  (cost=0.00..1.00 rows=100 width=64) (actual time=0.008..0.009 rows=7 loops=1)
 Planning Time: 0.116 ms
 Execution Time: 0.062 ms

Is there are any improvement I can make to my function definition so that planner can find a better plan for the (A) statement?

Cheers, Thierry