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: 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: 2017-09-21T15:24:17Z
Lists: pgsql-hackers 
> On 20 September 2017 at 17:19, Arthur Zakirov <a.zakirov@postgrespro.ru>
wrote:
> As a conclusion:
> * additional field are needed to pg_type for *_fetch and *_assign
functions to solve dependency problem

One last thing that I need to clarify. Initially there was an idea to
minimize
changes in `pg_type` - that's why I added only one column there that
contains an
OID of main subscripting function (and everything else you should find out
inside it). But I have no objections about adding more columns if everyone
is
ok with that. Basically pros and cons (marked as + and -):

one new column in `pg_type`:

* less intrusive (+)
* it's neccessary to make a dependency record between subscripting functions
  explicitly (-)

three new columns in `pg_type`:

* more intrusive (-)
* we can create a dependency record between subscripting functions
  simultaneously with a custom type creation (+)
* custom subscripting code does not need to resolve `fetch` and `assign`
  functions (+)

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.