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In-Reply-To: <us6m5jdjxmveyan77tdg2tysjls4yu3tsohpvjjedz6pnjkyn7@2g6b2asvgug3>
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Fri, 27 Mar 2026 17:17:25 -0400
Message-ID: 
 <CAAKRu_ZEddj8O10z7G2NfOG8bB+Qk+1V_Xt2YpnVS3bVJrjHLg@mail.gmail.com>
Subject: Re: Don't synchronously wait for already-in-progress IO in read
 stream
To: Andres Freund <andres@anarazel.de>
Cc: Nazir Bilal Yavuz <byavuz81@gmail.com>,
 Thomas Munro <thomas.munro@gmail.com>,
	pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>,
 Tomas Vondra <tv@fuzzy.cz>
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On Fri, Mar 27, 2026 at 1:29=E2=80=AFPM Andres Freund <andres@anarazel.de> =
wrote:
>
> On 2026-03-26 20:12:30 -0400, Andres Freund wrote:
> > One test used did_io=3D(t|f). That was actually only needed once "aio: =
Don't
> > wait for already in-progress IO" is in, as we might join the foreign IO=
. I
> > chose to hide that by making that part of the query "did_io and not
> > foreign_io", so we would detect if we were to falsely start IO ourselve=
s.
>
> I ended up not liking did_io, as that seems misleading when we just neede=
d to
> wait for a foreign IO.  I instead named it io_reqd.

0001 looks good to me except I don't get why you are still passing
MAIN_FORKNUM to PrefetchBuffer() in invalidate_one_block()

In 0002, the test cases look good to me. I haven't gained more
knowledge about injection point related code since my last review, so
still no comment there (inj_io_completion_hook(), etc).

I didn't see anything amiss reviewing by eye. Running it through AI,
it suggested that you should clear stdout between test cases in
test_inject_foreign. I think this seems most relevant because in two
back-to-back tests you are looking for the same output pattern.

It also pointed out that there is a pre-existing bug in
inj_io_short_read_hook() where you pass the wrong parameter to the log
message.

ereport(LOG, errmsg("short read injection point called, is enabled: %d",
                inj_io_error_state->enabled_reopen),
                errhidestmt(true), errhidecontext(true));

should be

ereport(LOG, errmsg("short read injection point called, is enabled: %d",
                inj_io_error_state->enabled_short_read),
                errhidestmt(true), errhidecontext(true));

0003 LGTM.

I am still in the process of reviewing 0004.

- Melanie