Re: Why are wait events not reported even though it reads/writes atimeline history file? - Mailing list pgsql-hackers

On 2020-04-28 15:09, Michael Paquier wrote:
> On Tue, Apr 28, 2020 at 02:49:00PM +0900, Fujii Masao wrote:
>> Isn't it safer to report the wait event during fgets() rather than 
>> putting
>> those calls around the whole loop, like other code does? For example,
>> writeTimeLineHistory() reports the wait event during read() rather 
>> than
>> whole loop.
> 
> Yeah, I/O wait events should be taken only during the duration of the
> system calls.  Particularly here, you may finish with an elog() that
> causes the wait event to be set longer than it should, leading to a
> rather incorrect state if a snapshot of pg_stat_activity is taken.
> --

Thanks for your comments.

I fixed it to report the wait event during fgets() only.
Please review the v2 patch I attached.

Regard,
-- 
Masahiro Ikeda