Re: Misuse of TimestampDifference() in the autoprewarm feature of pg_prewarm

Alexey Kondratov <a(dot)kondratov(at)postgrespro(dot)ru> writes:
> After looking on the autoprewarm code more closely I have realised that
> this 'double dump' issues was not an issues at all. I have just
> misplaced a debug elog(), so its second output in the log was only
> indicating that we calculated delay_in_ms one more time.

Ah --- that explains why I couldn't see a problem.

I've pushed 0001+0002 plus some followup work to fix other places
that could usefully use TimestampDifferenceMilliseconds(). I have
not done anything with 0003 (the TAP test for pg_prewarm), and will
leave that to the judgment of somebody who's worked with pg_prewarm
before. To me it looks like it's not really testing things very
carefully at all; on the other hand, we have exactly zero test
coverage of that module today, so maybe something is better than
nothing.

regards, tom lane