Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Dmitry Dolgov <9erthalion6@gmail.com>

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From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Arthur Zakirov <a.zakirov@postgrespro.ru>
Cc: Oleg Bartunov <obartunov@gmail.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, David Steele <david@pgmasters.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-11-14T21:25:00Z
Lists: pgsql-hackers 
> On 13 November 2017 at 14:11, Arthur Zakirov <a.zakirov@postgrespro.ru>
wrote:
> > I have a little complain about how ExprEvalStep gets resvalue. resvalue
is
> > assigned in one place (within ExecEvalSubscriptingRefFetch(),
> > ExecEvalSubscriptingRefAssign()), resnull is assigned in another place
> > (within jsonb_subscript_fetch(), jsonb_subscript_assign()).
>
> Hm...I'm afraid I don't get this. `resnull` is never assigned inside
> `jsonb_subscript_fetch` or `jsonb_subscript_assign`, instead it's coming
> from `ExecInterpExp` as `isnull` if I remember correctly. Are we talking
> about
> the same thing?
>
> No, I meant ExprEvalStep struct. For example, within
> ExecEvalSubscriptingRefFetch() you assign op->resvalue but op->resnull is
> leaved as unchanged

Oh, I see now, thanks for the explanation. Actually, it's how it was
implemented before in array subscripting, and I tried to be consistent with
this implementation. But now I wonder if `resnull` is really needed in
`jsonb_get_element`, `array_get_element` and it seems to me that I can even
get
rid of it so, that everything would be assigned in `jsonb_subscript_fetch`,
`array_subscript_fetch` - I'll send a new version of the patch soon.

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.