Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Pavel Stehule <pavel.stehule@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>, Thomas Munro <thomas.munro@enterprisedb.com>, Oleksandr Shulgin <oleksandr.shulgin@zalando.de>, 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>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-12-03T21:44:21Z
Lists: pgsql-hackers 
On Wed, Dec 2, 2020 at 10:18 PM Dmitry Dolgov <9erthalion6@gmail.com> wrote:
> > On Wed, Dec 02, 2020 at 11:52:54AM -0500, Tom Lane wrote:
> > Dmitry Dolgov <9erthalion6@gmail.com> writes:
> > >> On Mon, Nov 30, 2020 at 02:26:19PM +0100, Dmitry Dolgov wrote:
> > >>> On Mon, Nov 30, 2020 at 04:12:29PM +0300, Alexander Korotkov wrote:
> > >>> The idea of an opaque field in SubscriptingRef structure is more
> > >>> attractive to me.  Could you please implement it?
> >
> > >> Sure, doesn't seem to be that much work.
> >
> > I just happened to notice this bit.  This idea is a complete nonstarter.
> > You cannot have an "opaque" field in a parsetree node, because then the
> > backend/nodes code has no idea what to do with it for
> > copy/compare/outfuncs/readfuncs.  The patch seems to be of the opinion
> > that "do nothing" is adequate, which it completely isn't.
> >
> > Perhaps this is a good juncture at which to remind people that parse
> > tree nodes are read-only so far as the executor is concerned, so
> > storing something there only at execution time won't work either.
>
> Oh, right, stupid of me. Then I'll just stick with the original
> Alexanders suggestion.

Stupid me too :)

I didn't get we can't add opaque field to SubscriptingRefState without
adding it to SubscriptingRef, which has to support
copy/compare/outfuncs/readfuncs

------
Regards,
Alexander Korotkov

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.