From: Chao Li <li.evan.chao@gmail.com>
Message-Id: <0D17D4E1-919F-4412-8EFE-BEB80211321D@gmail.com>
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Subject: Re: Use proc_exit() in WalRcvWaitForStartPosition
Date: Fri, 10 Apr 2026 15:07:03 +0800
In-Reply-To: 
 <CAHGQGwHHrDv8Z=D-UP+-RUR2yntv3Ab=yw4_uPWEMY0vLX_O6g@mail.gmail.com>
Cc: Xuneng Zhou <xunengzhou@gmail.com>,
 Andreas Karlsson <andreas@proxel.se>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
To: Fujii Masao <masao.fujii@gmail.com>
References: <74381238-4E8A-4621-B794-57025DCCE0BA@gmail.com>
 <6a42c40e-eb81-4212-9bca-8c0eb02d47d1@proxel.se>
 <CABPTF7V=y2rHC=gLTeC-42aRc+jcXueomUBjbNiy3pOfhJs3_A@mail.gmail.com>
 <CAHGQGwHHrDv8Z=D-UP+-RUR2yntv3Ab=yw4_uPWEMY0vLX_O6g@mail.gmail.com>
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> On Apr 10, 2026, at 14:16, Fujii Masao <masao.fujii@gmail.com> wrote:
>=20
> On Thu, Apr 9, 2026 at 10:09=E2=80=AFAM Xuneng Zhou =
<xunengzhou@gmail.com> wrote:
>>=20
>> On Thu, Apr 9, 2026 at 5:00=E2=80=AFAM Andreas Karlsson =
<andreas@proxel.se> wrote:
>>>=20
>>> On 4/8/26 11:08 AM, Chao Li wrote:
>>>> While working on another patch, I happened to notice that =
WalRcvWaitForStartPosition() calls raw exit(1). I think this should use =
proc_exit(1) instead, so that the normal cleanup machinery is not =
bypassed.
>>>>=20
>>>> This tiny patch just replaces exit(1) with proc_exit(1) in =
WalRcvWaitForStartPosition().
>>>=20
>>> This looks likely to be correct since when we exit in =
WalReceiverMain()
>>> (on WALRCV_STOPPING and WALRCV_STOPPED) we call proc_exit(1). I feel =
we
>>> should exit the same way in WalRcvWaitForStartPosition() as we do in
>>> WalReceiverMain() and if not I would like a comment explaining why =
those
>>> two cases are different.
>>=20
>> +1
>=20
> +1
>=20
>=20
>> WalRcvWaitForStartPosition, WALRCV_STOPPING before entering wait loop
>> uses proc_exit(0) for WALRCV_STOPPING, while this path should =
probably
>> use proc_exit(0) as well (not proc_exit(1)), since the stop was a
>> requested shutdown, not an error. Using exit code 1 for a clean
>> stop-on-request seems inconsistent.
>=20
> The requested shutdown is handled in ShutdownWalRcv(), which sets the =
state to
> WALRCV_STOPPING and sends SIGTERM to the walreceiver.
>=20
> Although this might be considered a normal shutdown (suggesting exit =
code 0),
> when the walreceiver receives SIGTERM it exits via ereport(FATAL), =
resulting
> in exit code 1. In contrast, if it exits early in =
WalRcvWaitForStartPosition()
> due to the WALRCV_STOPPING state, it uses exit code 0, as you noted. =
So
> there seems to be some inconsistency in exit codes.
>=20
> That said, the exit code (0 vs 1) does not affect behavior, since
> the postmaster treats both as non-crash exits.
>=20
> For consistency, I would prefer using exit code 1 in proc_exit() in
> WalRcvWaitForStartPosition(), to match the ereport(FATAL) path. But =
I'm fine
> with other approaches as well.
>=20
> Also, the comment at the top of walreceiver.c may need updating:
>=20
> * Normal termination is by SIGTERM, which instructs the walreceiver to
> * exit(0). Emergency termination is by SIGQUIT; like any postmaster =
child
> * process, the walreceiver will simply abort and exit on SIGQUIT. A =
close
> * of the connection and a FATAL error are treated not as a crash but =
as
> * normal operation.
>=20
> Regards,
>=20
> --=20
> Fujii Masao

PFA v2 - updated header comment of walreceive.c. I tried to avoid =
mentioning the exact exit value in the comment, so I just changed =
=E2=80=9Cexit(0)=E2=80=9D to =E2=80=9Cterminate=E2=80=9D.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/


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=20=0A--=20=0A2.50.1=20(Apple=20Git-155)=0A=0A=

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