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: Tom Lane <tgl@sss.pgh.pa.us>, 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: 2020-08-05T14:04:22Z
Lists: pgsql-hackers

Attachments

> On Sun, Aug 02, 2020 at 12:50:12PM +0200, Pavel Stehule wrote:
> >
> > > Maybe this could be salvaged by flushing 0005 in its current form and
> > > having the jsonb subscript executor do something like "if the current
> > > value-to-be-subscripted is a JSON array, then try to convert the textual
> > > subscript value to an integer".  Not sure about what the error handling
> > > rules ought to be like, though.
> >
> > I'm fine with the idea of separating 0005 patch and potentially prusuing
> > it as an independent item. Just need to rebase 0006, since Pavel
> > mentioned that it's a reasonable change he would like to see in the
> > final result.
> >
>
> +1

Here is what I had in mind. Worth noting that, as well as the original
patch, the attached implementation keeps the same behaviour for negative
indices. Also, I've removed a strange inconsistency one could notice
with the original implementation, when one extra gap was introduced when
we append something at the beginning of an array.

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.