Re: [PATCH] add --progress option to pgbench (submission 3)

Fabien COELHO <coelho@cri.ensmp.fr> writes:
>>> Here is a v4 that takes into account most of your points: The report is
>>> performed for all threads by thread 0, however --progress is not supported
>>> under thread fork emulation if there are more than one thread. The report
>>> time does not slip anymore.

>> I don't believe that to be an acceptable restriction.

> My first proposal is to remove the fork emulation altogether, which would 
> remove many artificial limitations to pgbench and simplify the code 
> significantly. That would be an improvement.

I would object strongly to that, as it would represent a significant
movement of the goalposts on what is required to build Postgres at all,
ie platforms on which --enable-thread-safety is unavailable or expensive
would be out in the cold.  Perhaps that set is approaching empty, but a
project that's still standardized on C89 has little business making such
a choice IMO.

> Otherwise, he simplest possible adaptation, if it is required to have the 
> progress feature under fork emulation to pass it, is that under "fork 
> emulation" each processus reports its current progress instead of having a 
> collective summing.

Perhaps that's worth doing.  I agree with Fabien that full support of
this feature in the process model is more trouble than it's worth,
though, and I wouldn't scream loudly if we just didn't support it.
--disable-thread-safety doesn't have to be entirely penalty-free.
        regards, tom lane