Re: droped out precise time calculations in src/interfaces/libpq/fe-connect.c

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Denis A Ustimenko wrote:
> >> Beware of almost 1 second posiible error. For example: connect_timeout == 1,
> >> we start at 0.999999 then finish_time == 1. If CPU is quite busy we will
> >> do only one iteration. I don't know is it enough to make connection?
> >> True timeout in this case == 0.000001
> 
> > Good question.  What is going to happen is that select() is going to be
> > passed tv_sec = 1, and it is going to sleep for one second.  Now, if
> > select is interrupted, another time() call is going to be made.
> 
> There is a very simple answer to this, which I think I suggested to Joe
> originally, but it's not in the code now: the initial calculation of
> finish_time = now() + timeout must add one.  This ensures that any
> roundoff error is in the conservative direction of timing out later,
> rather than sooner.

Yes, I saw that and will try to add it back into the code.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073