On 06/06/2023 10:24, Tristan Partin wrote:
Hello,
Today, I compiled the master branch of Postgres with the following GCC
version:
gcc (GCC) 13.1.1 20230511 (Red Hat 13.1.1-2)
I got the following warning:
[701/2058] Compiling C object
src/backend/postgres_lib.a.p/access_transam_xlogrecovery.c.o
In function ‘recoveryStopsAfter’,
inlined from ‘PerformWalRecovery’ at
../src/backend/access/transam/xlogrecovery.c:1749:8:
../src/backend/access/transam/xlogrecovery.c:2756:42: warning: ‘recordXtime’
may be used uninitialized [-Wmaybe-uninitialized]
2756 | recoveryStopTime = recordXtime;
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
../src/backend/access/transam/xlogrecovery.c: In function ‘PerformWalRecovery’:
../src/backend/access/transam/xlogrecovery.c:2647:21: note: ‘recordXtime’ was
declared here
2647 | TimestampTz recordXtime;
| ^~~~~~~~~~~
Investigating this issue I see a potential assignment in
xlogrecovery.c:2715. Best I can tell the warning looks real. Similar
functions in this file seem to initialize recordXtime to 0. Attached is
a patch which does just that.
Thank you! My refactoring in commit c945af80cf introduced this. Looking
at getRecordTimestamp(), it will always return true and set recordXtime
for the commit and abort records, and some compilers can deduce that.
Initializing to 0 makes sense, I'll commit that fix later tonight.
--
Heikki Linnakangas
Neon (https://neon.tech)