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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Allowing parallel-safe initplans
Date: Tue, 18 Apr 2023 09:33:57 -0400
Message-ID: <2636188.1681824837@sss.pgh.pa.us> (raw)
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Richard Guo <guofenglinux@gmail.com> writes:
> On Mon, Apr 17, 2023 at 11:04 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I wondered about that too, but how come neither of us saw non-cosmetic
>> failures (ie, actual query output changes not just EXPLAIN changes)
>> when we tried this?

> Sorry I forgot to mention that I did see query output changes after
> moving the initPlans to the Gather node.

Hmm, my memory was just of seeing the EXPLAIN output changes, but
maybe those got my attention to the extent of missing the others.

> It seems that in this case the top_plan does not have any extParam, so
> the Gather node that is added atop the top_plan does not have a chance
> to get its initParam filled in set_param_references().

Oh, so maybe we'd need to copy up extParam as well?  But it's largely
moot, since I don't see a good way to avoid breaking the EXPLAIN
output.

			regards, tom lane





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