Re: Fix bug of clearing of waitStart in ProcWakeup()

Chao Li <li.evan.chao@gmail.com> 于2026年2月24日周二 14:29写道：

> Hi,
>
> I just noticed this while reviewing patch [1]. It looks like this is
> caused by a simple typo.
>
> In ProcWakeup():
> ```
> PGPROC *
> ProcWakeup(PGPROC *proc, ProcWaitStatus waitStatus)
> {
>         PGPROC     *retProc;
>
>         /* Proc should be sleeping ... */
>         if (proc->links.prev == NULL ||
>                 proc->links.next == NULL)
>                 return NULL;
>         Assert(proc->waitStatus == PROC_WAIT_STATUS_WAITING);
>
>         /* Save next process before we zap the list link */
>         retProc = (PGPROC *) proc->links.next;
>
>         /* Remove process from wait queue */
>         SHMQueueDelete(&(proc->links));
>         (proc->waitLock->waitProcs.size)--;
>
>         /* Clean up process' state and pass it the ok/fail signal */
>         proc->waitLock = NULL;
>         proc->waitProcLock = NULL;
>         proc->waitStatus = waitStatus;
>         pg_atomic_write_u64(&MyProc->waitStart, 0); <== Here, it should
> operate on proc
>
>         /* And awaken it */
>         SetLatch(&proc->procLatch);
>
>         return retProc;
> }
> ```
>
> Since this function is clearly operating on the parameter proc, the only
> statement that touches MyProc looks suspicious. It should reset
> proc->waitStart, not MyProc->waitStart.
>
> As written, it will incorrectly clear the caller’s waitStart instead of
> the awakened backend’s, potentially leaving a stale waitStart value in the
> target PGPROC.
>
> [1]
> https://postgr.es/m/CAHGQGwGw4LhNwOGQT3nbw3uWy8gL94_MB4T39Wfr4_Vgopuovg@mail.gmail.com
>
> Best regards,
> --
> Chao Li (Evan)
> HighGo Software Co., Ltd.
> https://www.highgo.com/
>
>
>
>
>
>
>
Hi ,

The fix looks correct to me. I applied it locally and build and "make
check" passed from my side.

Regards,
ji xu