Horton

Re: [HACKERS] MERGE SQL Statement for PG11

Simon Riggs <simon@2ndquadrant.com>

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From: Simon Riggs <simon@2ndquadrant.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, Pavan Deolasee <pavan.deolasee@2ndquadrant.com>, Peter Geoghegan <pg@bowt.ie>, Stephen Frost <sfrost@snowman.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-01-29T16:51:07Z
Lists: pgsql-hackers 
On 29 January 2018 at 16:44, Bruce Momjian <bruce@momjian.us> wrote:

> I think the question is how does it handle cases it doesn't support?
> Does it give wrong answers?  Does it give a helpful error message?  Can
> you summarize that?

I'm happy to report that it gives correct answers to every known MERGE
test, except

* where it hits a concurrency issue and throws SQLCODE =
ERRCODE_T_R_SERIALIZATION_FAILURE and the standard text for that

* where it hits an unsupported feature and throws SQLCODE =
ERRCODE_FEATURE_NOT_SUPPORTED, with appropriate text

but of course Robert is correct and everything benefits from further review.

-- 
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Add support for MERGE SQL command

  2. Add API of sorts for transition table handling in trigger.c

  3. Revert MERGE patch

  4. Fix several bugs related to ON CONFLICT's EXCLUDED pseudo relation.