Re: support for MERGE - Mailing list pgsql-hackers

From Zhihong Yu
Subject Re: support for MERGE
Date
Msg-id CALNJ-vTr=gR+jQNUAn68ozFf1eCpCc2599oo=bkEW_Rr5xo9WA@mail.gmail.com
Whole thread Raw
In response to Re: support for MERGE  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
Responses Re: support for MERGE
List pgsql-hackers


On Wed, Mar 9, 2022 at 9:38 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
I attach MERGE v14.  This includes a fix from Amit Langote for the
problem I described previously, with EvalPlanQual not working correctly.
(I had failed to short-circuit the cross-partition update correctly.)
Now the test case is enabled again, and it passes with the correct
output.

0001 is as before; the only change is that I've added a commit message.
Since this just moves some code around, I intend to get it pushed very
soon.

0002 is the ExecUpdate/ExecDelete split.  I cleaned up the struct
definitions a bit more, but it's pretty much as in the previous version.

0003 is the actual MERGE implementation.  Many previous review comments
have been handled, and several other things are cleaner than before.
I haven't made any changes for work_mem handling in ModifyTable's
transition tables, though, and haven't attempted to address concurrent
INSERT.

--
Álvaro Herrera           39°49'30"S 73°17'W  —  https://www.EnterpriseDB.com/

Hi,
For v14-0002-Split-ExecUpdate-and-ExecDelete-in-reusable-piec.patch :

+   TupleTableSlot *insertProjectedTuple;

With `insert` at the beginning of the variable name, someone may think it is a verb. How about naming the variable projectedTupleFromInsert (or something similar) ?

+       if (!ExecBRDeleteTriggers(context->estate, context->epqstate,
+                                 resultRelInfo, tupleid, oldtuple,
+                                 epqreturnslot))
+           /* some trigger made the delete a no-op; let caller know */
+           return false;

It seems you can directly return the value returned from ExecBRDeleteTriggers().

+       if (!ExecBRUpdateTriggers(context->estate, context->epqstate,
+                                 resultRelInfo, tupleid, oldtuple, slot))
+           /* some trigger made the update a no-op; let caller know */
+           return false;

Similar comment as above (the comment is good and should be kept).

Cheers

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