Hi,
I see that in the archiver code, in the function pgarch_MainLoop,
the archiver sleeps for a certain time or until there's a signal. The time
it sleeps for is represented by:
timeout = PGARCH_AUTOWAKE_INTERVAL - (curtime - last_copy_time);
It so happens that last_copy_time and curtime are always set at the same
time which always makes timeout equal (actually roughly equal) to
PGARCH_AUTOWAKE_INTERVAL.
I see that this behaviour was introduced as a part of the commit:
d75288fb27b8fe0a926aaab7d75816f091ecdc27. The discussion thread is:
The change was introduced in v31, with the following comment in the
discussion thread:
- pgarch_MainLoop start the loop with wakened = true when both
notified or timed out. Otherwise time_to_stop is set and exits from
the loop immediately. So the variable wakened is actually
useless. Removed it.
This behaviour was different before the commit: d75288fb27b8fe0a926aaab7d75816f091ecdc27,
in which the archiver keeps track of how much time has elapsed since last_copy_time
in case there was a signal, and it results in a smaller subsequent value of
timeout, until timeout is zero. This also avoids calling pgarch_ArchiverCopyLoop
before PGARCH_AUTOWAKE_INTERVAL in case there's an intermittent signal.
With the current changes it may be okay to always sleep for PGARCH_AUTOWAKE_INTERVAL,
but that means curtime and last_copy_time are no more needed.
I would like to validate if my understanding is correct, and which of the
behaviours we would like to retain.
Thanks & Regards,
Sravan Velagandula
The Enterprise PostgreSQL Company
