Horton

Re: [HACKERS] [PATCH] Generic type subscripting

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Pavel Stehule <pavel.stehule@gmail.com>, 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: 2020-12-09T21:59:34Z
Lists: pgsql-hackers

Attachments

Here's a couple of little finger exercises to move this along a bit.

0001 adds the ability to attach a subscript handler to an existing
data type with ALTER TYPE.  This is clearly going to be necessary
if we want extension types to be able to use this facility.  The
only thing that I think might be controversial here is that I did
not add the ability to set pg_type.typelem.  While that'd be easy
enough so far as ALTER TYPE is concerned, I'm not sure that we want
to encourage people to change it.  The dependency rules mean that
the semantics of typelem aren't something you really want to change
after-the-fact on an existing type.  Also, if we did allow it, any
existing SubscriptingRef.refelemtype values in stored views would
fail to be updated.

0002 makes use of that to support subscripting of hstore.  I'm not
sure how much we care about that from a functionality standpoint,
but it seems like it might be good to have a contrib module testing
that extensions can use this.  Also, I thought possibly an example
showing what's basically the minimum possible amount of complexity
would be good to have.  If people like this, I'll finish it up (it
lacks docs) and add it.

			regards, tom lane

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.