Horton

Re: SQL/JSON features for v15

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, "Jonathan S. Katz" <jkatz@postgresql.org>, Andrew Dunstan <andrew@dunslane.net>, Amit Langote <amitlangote09@gmail.com>, Nikita Glukhov <n.gluhov@postgrespro.ru>, Alvaro Herrera <alvherre@alvh.no-ip.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Michael Paquier <michael@paquier.xyz>, John Naylor <john.naylor@enterprisedb.com>
Date: 2022-08-31T17:09:51Z
Lists: pgsql-hackers 
On Wed, Aug 31, 2022 at 1:06 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> The currently proposed patchset hacks up a relatively small number
> of core datatypes to be able to do that.  But it's just a hack
> and there's no prospect of extension types being able to join
> in the fun.  I think where we need to start, for v16, is making
> an API design that will let any datatype have this functionality.

This would be really nice to have.

> (I don't say that we'd convert every datatype to do so right away;
> in the long run we should, but I'm content to start with just the
> same core types touched here.)

I would be in favor of making more of an effort than just a few token
data types. The initial patch could just touch a few, but once the
infrastructure is in place we should really make a sweep through the
tree and tidy up.

> Beside the JSON stuff, there is
> another even more pressing application for such behavior, namely
> the often-requested COPY functionality to be able to shunt bad data
> off somewhere without losing the entire transfer.  In the COPY case
> I think we'd want to be able to capture the error message that
> would have been issued, which means the current patches are not
> at all appropriate as a basis for that API design: they're just
> returning a bool without any details.

Fully agreed.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. JSON_TABLE: Add support for NESTED paths and columns

  2. Add basic JSON_TABLE() functionality

  3. Add SQL/JSON query functions

  4. Add soft error handling to some expression nodes

  5. Adjust populate_record_field() to handle errors softly

  6. Refactor code used by jsonpath executor to fetch variables

  7. Add more SQL/JSON constructor functions

  8. SQL/JSON: support the IS JSON predicate

  9. SQL/JSON: add standard JSON constructor functions

  10. Revert SQL/JSON features

  11. Numeric error suppression in jsonpath