Horton

Re: support for MERGE

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-01-18T16:48:18Z
Lists: pgsql-hackers 
On 2021-Jan-18, Robert Haas wrote:

> On Thu, Dec 31, 2020 at 8:48 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> > Here's a rebase of Simon/Pavan's MERGE patch to current sources.  I
> > cleaned up some minor things in it, but aside from rebasing, it's pretty
> > much their work (even the commit message is Simon's).
> 
> It's my impression that the previous discussion concluded that their
> version needed pretty substantial design changes. Is there a plan to
> work on that? Or was some of that stuff done already?

I think some of the issues were handled as I adapted the patch to
current sources.  However, the extensive refactoring that had been
recommended in the old threads has not been done.  I have these two
comments mainly:

https://postgr.es/m/CABOikdOeraX0RKojBs0jZxY5SmbQF3GJBP0+Rat=2g+VQsA+9g@mail.gmail.com
https://postgr.es/m/7168.1547584387@sss.pgh.pa.us

I'll try to get to those, but I have some other patches that I need to
handle first.

-- 
Álvaro Herrera       Valdivia, Chile

Commits

  1. Doc fixes for MERGE statement

  2. MERGE docs adjustments

  3. Link to MVCC docs in MERGE docs

  4. Fix EXPLAIN MERGE output when no tuples are processed

  5. Make EXPLAIN MERGE output format more compact

  6. Add support for MERGE SQL command

  7. Split ExecUpdate and ExecDelete into reusable pieces

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

  9. Represent Lists as expansible arrays, not chains of cons-cells.