Subject: Re: [HACKERS] MERGE SQL Statement for PG11
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Peter Geoghegan <pg@bowt.ie>, Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>,
 Alvaro Herrera <alvherre@alvh.no-ip.org>,
 Andrew Dunstan <andrew.dunstan@2ndquadrant.com>,
 Pavan Deolasee <pavan.deolasee@2ndquadrant.com>,
 Stephen Frost <sfrost@snowman.net>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
References: 
 <CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com>
 <CANP8+j+rO5jnDATve3gokRf6Jhfss5DquFxgz74rhJero8sAGQ@mail.gmail.com>
 <CA+TgmoavFdPbCeB+QUSdeQieW2rhCdR54qndO_8irHOXrCjxUg@mail.gmail.com>
 <CANP8+jLzhsmvL7fVgikCUR-ZhUCZ3JnMCGjgS49uTsCzvuNCBw@mail.gmail.com>
 <CAH2-WzmfysiLsmvmtGsd1zt25APKiHxJN20N9sDGoHYrBSUEgA@mail.gmail.com>
 <CANP8+jJYeYKjoH7TYXRvDBcG3jRWJz99hw3ubVKMUXrVko9BYQ@mail.gmail.com>
 <CAH2-WzmMpW97m_uAiVfTF1swA06KREbEkKftX6WBcYoAVi867g@mail.gmail.com>
 <CAH2-Wz=xVcWiErLo9t7og8FFL2-kKYRHY7sOxD2_bmDAaQVffQ@mail.gmail.com>
 <CANP8+jKz71SvyH0-kUvh4ZEamZ+qV0wDoRrY-4Zjpw9NVxXJyw@mail.gmail.com>
 <CAH2-Wzn_YAWLJqyByVfrHSskQP029AyZQ_fGNbV16wTC4z6f_g@mail.gmail.com>
 <CANP8+jLDsGOAx2bWL-coFZCYTXWO9NYYb5QbS-d43K4n5-AhFw@mail.gmail.com>
 <CA+TgmoZRUE5nk_Er4MpLEYAzcrRZ-BTTymg4_ayY3AUjx9U3OQ@mail.gmail.com>
 <CAH2-WznrH8d_9LwjfO1YEn-WbYJhadXS3XmG-G5BLYe=c3yqdA@mail.gmail.com>
 <50394f44-af78-b40f-313a-5b0f8a0450e4@2ndquadrant.com>
Message-ID: <751b62c0-87a2-d109-3291-ea78289075ca@2ndquadrant.com>
Date: Thu, 1 Mar 2018 23:22:46 +0100
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On 02/06/2018 03:40 PM, Tomas Vondra wrote:
> 
> 
> I plan to go through the patch and this thread over the couple of
> days, and summarize what the current status is (or my understanding
> of it). That is (a) what are the missing pieces, (b) why are they
> missing, (c) how we plan to address them in the future and (d)
> opinions on these issues expressed by others on this thread.
> 

So, I've promised a summary of the patch status about three weeks ago.
I've been postponing that as Pavan was moving the patch forward pretty
quickly, and now there's not much to summarize ... which is a good thing
I guess.

If my understanding is correct, the MERGE now supports both partitioning
and RLS, and subselects should also work on various places (which is
somewhat consistent with my impression claims about SQL standard
prohibiting them were not entirely accurate).

Which leaves us with figuring out the right concurrency behavior, and
that discussion seems to be in progress.

So at this point I'm not aware of any other missing features in the
patch, and a more detailed summary is not really needed.


regards

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