Re: Refine comments on usage WL_POSTMASTER_DEATH vs WL_EXIT_ON_PM_DEATH

On 23/10/2024 12:18, Pavel Borisov wrote:
> Hi, Hackers!
> 
> Current comments on the usage of WL_POSTMASTER_DEATH state that it 
> should be used for scenarios of finishing other than immediately i.e. 
> returning values and waiting for postmaster dies.
> In fact, in parts of the code, it's currently used to immediately exit 
> or throw FATAL (in the walsender and in libpq).
> 
> So I propose change the comments on WL_POSTMASTER_DEATH stating that it 
> could be used for both cases: for processing and setting return values 
> if that's needed, and for immediate exit otherwise.

I see what you mean, but I don't think the proposed patch is making it 
better. With WL_POSTMASTER_DEATH, the WaitLatch call returns if the 
postmaster dies. What the caller does then is the caller's business. 
That's different from WL_EXIT_ON_PM_DEATH in that with 
WL_EXIT_ON_PM_DEATH, WaitLatch itself will do the exit(), not the caller.

-- 
Heikki Linnakangas
Neon (https://neon.tech)