Re: [HACKERS] [PATCH] Generic type subscripting

čt 31. 12. 2020 v 15:27 odesílatel Dmitry Dolgov <9erthalion6(at)gmail(dot)com>
napsal:

> > On Wed, Dec 30, 2020 at 09:01:37PM +0100, Dmitry Dolgov wrote:
> > > make check fails
> >
> > Yeah, apparently I forgot to enable asserts back after the last
> > benchmarking discussion, and missed some of those. Will fix.
> >
> > > 2. The index position was ignored.
> > >
> > > postgres=# update foo set a['a'][10] = '20';
> > > UPDATE 1
> > > postgres=# select * from foo;
> > > ┌─────────────┐
> > > │ a │
> > > ╞═════════════╡
> > > │ {"a": [20]} │
> > > └─────────────┘
> > > (1 row)
> >
> > I just realized I haven't included "filling the gaps" part, that's why
> > it works as before. Can add this too.
> >
> > > 1. quietly ignored update
> > >
> > > postgres=# update foo set a['a'][10] = '20';
> > > UPDATE 1
> > > postgres=# select * from foo;
> > > ┌────┐
> > > │ a │
> > > ╞════╡
> > > │ {} │
> > > └────┘
> > > (1 row)
> >
> > This belongs to the original jsonb_set implementation. Although if we
> > started to change it anyway with "filling the gaps", maybe it's fine to
> > add one more flag to tune its behaviour in this case as well. I can
> > check how complicated that could be.
>
> Here is what I had in mind. Assert issue in main patch is fixed (nothing
> serious, it was just the rawscalar check for an empty jsonb created
> during assignment), and the second patch contains all the bits with
> "filling the gaps" including your suggestion about creating the whole
> path if it's not present. The latter (creating the chain of empty
> objects) I haven't tested that much, but if there are any issues or
> concerns I guess it will not prevent the main patch from going forward

the tests passed and filling gaps works well

but creating empty objects doesn't work

create table foo(a jsonb);

insert into foo values('{}');

postgres=# update foo set a['k'][1] = '20';
UPDATE 1
postgres=# select * from foo;
┌───────────────────┐
│ a │
╞═══════════════════╡
│ {"k": [null, 20]} │
└───────────────────┘
(1 row)

it is ok

postgres=# update foo set a['k3'][10] = '20';
UPDATE 1
postgres=# select * from foo;
┌───────────────────┐
│ a │
╞═══════════════════╡
│ {"k": [null, 20]} │
└───────────────────┘
(1 row)

the second update was not successful

.
>