Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Pavel Stehule <pavel.stehule@gmail.com>

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From: Pavel Stehule <pavel.stehule@gmail.com>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, 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: 2021-01-07T08:24:22Z
Lists: pgsql-hackers 
čt 7. 1. 2021 v 9:15 odesílatel Dmitry Dolgov <9erthalion6@gmail.com>
napsal:

> > On Wed, Jan 06, 2021 at 09:22:53PM +0100, Pavel Stehule wrote:
> >
> > this case should to raise exception - the value should be changed or
> error
> > should be raised
> >
> > postgres=# insert into foo values('{}');
> > postgres=# update foo set a['a'] = '100';
> > postgres=# update foo set a['a'][1] = '-1';
> > postgres=# select * from foo;
> > ┌────────────┐
> > │     a      │
> > ╞════════════╡
> > │ {"a": 100} │
> > └────────────┘
>
> I was expecting this question, as I've left this like that intentionally
> because of two reasons:
>
> * Opposite to other changes, to implement this one we need to introduce
>   a condition more interfering with normal processing, which raises
>   performance issues for already existing functionality in jsonb_set.
>
> * I vaguely recall there was a similar discussion about jsonb_set with
>   the similar solution.
>

ok.

In this case I have a strong opinion so current behavior is wrong. It can
mask errors. There are two correct possibilities

1. raising error - because the update try to apply index on scalar value

2. replace by array - a = {NULL, -1}

But isn't possible ignore assignment

What do people think about it?




> For the references what I mean I've attached the third patch, which does
> this. My opinion would be to not consider it, but I'm fine leaving this
> decision to committer.
>

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.