Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Dmitry Dolgov <9erthalion6@gmail.com>

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From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Oleksandr Shulgin <oleksandr.shulgin@zalando.de>, Artur Zakirov <a.zakirov@postgrespro.ru>, Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Michael Paquier <michael.paquier@gmail.com>, Oleg Bartunov <obartunov@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, David Steele <david@pgmasters.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-11-07T18:36:15Z
Lists: pgsql-hackers 
> On Wed, 7 Nov 2018 at 17:09, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>
> I don't agree. If we use a  same syntax for some objects types, we should to enforce some consistency.

Just to make it clear, consistency between what?

> I don't think so you should to introduce nulls for JSONs. In this case, the most correct solution is raising a exception.

Now it's my turn to disagree. As an argument I have this thread [1], where
similar discussion happened about flexibility of jsonb and throwing an errors
(in this particular case whether or not to throw an error when a non existing
path was given to jsonb_set).

I can imagine significant number of use cases when adding a value to jsonb like
that is desirable outcome, and I'm not sure if I can come up with an example
when strictness is the best result. Maybe if you have something in mind, you
can describe what would be the case for that? Also as I've mentioned before,
consistency between jsonb_set and jsonb subscripting operator will help us to
avoid tons of question about why I can do this and this using one option, but
not another.

[1]: https://www.postgresql.org/message-id/CAM3SWZT3uZ7aFktx-nNEWGbapN1oy2t2gt10pnOzygZys_Ak1Q%40mail.gmail.com

Commits

  1. Throw error when assigning jsonb scalar instead of a composite object

  2. Filling array gaps during jsonb subscripting

  3. Implementation of subscripting for jsonb

  4. Allow ALTER TYPE to update an existing type's typsubscript value.

  5. Allow subscripting of hstore values.

  6. Support subscripting of arbitrary types, not only arrays.

  7. jit: Reference function pointer types via llvmjit_types.c.

  8. Teach contain_leaked_vars that assignment SubscriptingRefs are leaky.

  9. jit: Correct parameter type for generated expression evaluation functions.

  10. Renaming for new subscripting mechanism

  11. Fix assertion failure for SSL connections.

  12. Teach eval_const_expressions() to handle some more cases.