Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Dmitry Dolgov <9erthalion6@gmail.com>

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From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, Andres Freund <andres@anarazel.de>, Alexander Korotkov <aekorotkov@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, David Steele <david@pgmasters.net>, Nikita Glukhov <n.gluhov@postgrespro.ru>, Alvaro Herrera <alvherre@2ndquadrant.com>, David Fetter <david@fetter.org>, Thomas Munro <thomas.munro@gmail.com>, Oleksandr Shulgin <oleksandr.shulgin@zalando.de>, Robert Haas <robertmhaas@gmail.com>, Michael Paquier <michael.paquier@gmail.com>, Oleg Bartunov <obartunov@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-12-18T19:59:25Z
Lists: pgsql-hackers 
> On Thu, Dec 17, 2020 at 03:29:35PM -0500, Tom Lane wrote:
> Dmitry Dolgov <9erthalion6@gmail.com> writes:
> > On Thu, Dec 17, 2020 at 01:49:17PM -0500, Tom Lane wrote:
> >> We can certainly reconsider the API for the parsing hook if there's
> >> really a good reason for these to be different types, but it seems
> >> like that would just be encouraging poor design.
>
> > To be more specific, this is the current behaviour (an example from the
> > tests) and it doesn't seem right:
>
> >     =# update test_jsonb_subscript
> >        set test_json['a'] = 3 where id = 1;
> >     UPDATE 1
> >     =# select jsonb_typeof(test_json->'a')
> >        from test_jsonb_subscript where id = 1;
> >      jsonb_typeof
> >      --------------
> >       string
>
>
> I'm rather inclined to think that the result of subscripting a
> jsonb (and therefore also the required source type for assignment)
> should be jsonb, not just text.  In that case, something like
> 	update ... set jsoncol['a'] = 3
> would fail, because there's no cast from integer to jsonb.  You'd
> have to write one of
> 	update ... set jsoncol['a'] = '3'
> 	update ... set jsoncol['a'] = '"3"'
> to clarify how you wanted the input to be interpreted.
> But that seems like a good thing, just as it is for jsonb_in.

Yep, that makes sense, will go with this idea.

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.