Horton

Re: [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: Tom Lane <tgl@sss.pgh.pa.us>, David Steele <david@pgmasters.net>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-09-16T22:27:58Z
Lists: pgsql-hackers 
> On 17 September 2017 at 00:04, Arthur Zakirov <a.zakirov@postgrespro.ru>
wrote:
>
> In my opinion, 'DEPENDS ON' syntax is not actually appropriate here. It
> also looks like a not very good hack to me.

Hm...why do you think about it as a hack?

> Moreover user can implement subscripting to its own type without using
> 'DEPENDS ON' syntax. And he will face the bug mentioned above too.

Yes, but since it will require from a user to create few independent custom
functions for subscripting (as we discussed before, there were few reasons
of
having them as a proper separate function), I don't see how to avoid this
step
of explicitly marking all of them as related to a subscripting logic for
particular data type. And therefore it's possible to forget to do that step
in
spite of what form this step will be. Maybe it's possible to make something
like `CREATE FUNCTION ... FOR SUBSCRIPTING`, then verify that assign/extract
functions are presented and notify user if he missed them (but I would
rather
not do this unless it's really necessary, since it looks like an overkill).

But I'm open to any suggestions, do you have something in mind?

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.