Horton

Re: Bypassing cursors in postgres_fdw to enable parallel plans

Alexander Pyhalov <a.pyhalov@postgrespro.ru>

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From: Alexander Pyhalov <a.pyhalov@postgrespro.ru>
To: Rafia Sabih <rafia.pghackers@gmail.com>
Cc: KENAN YILMAZ <kenan.yilmaz@localus.com.tr>, Robert Haas <robertmhaas@gmail.com>, Andy Fan <zhihuifan1213@163.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-12-17T14:09:28Z
Lists: pgsql-hackers

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Rafia Sabih писал(а) 2025-11-27 13:50:
> On Tue, 25 Nov 2025 at 15:24, KENAN YILMAZ
> <kenan.yilmaz@localus.com.tr> wrote:
> 
>> Hello Hackers,
>> 
>> I have executed use_cursor = true/false with quick tests.
>> 

Hi.

I've looked at this patch, because also was playing with tuplestore in 
PgFdwScanState to have more predictable memory usage with large 
fetch_size. Unfortunately, I've found that you can't use 
TTSOpsMinimalTuple(?) tuplestore to store tuple's ctid. I hoped this 
patch provides some solution for this issue, but no, it seems have the 
same problem. Attaching test case with a reproducer.
-- 
Best regards,
Alexander Pyhalov,
Postgres Professional