Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement)

On 7/17/13 2:31 AM, Tatsuo Ishii wrote:
> ./pgbench -p 5433 -S -T 10 -R 10000 test
> average rate limit lag: 862.534 ms (max 2960.913 ms)
> tps = 7133.745911 (including connections establishing)
> tps = 7135.130810 (excluding connections establishing)
>
> What does "average rate limit lag" mean?

The whole concept of "lag" with the rate limit is complicated. At one
point I thought this should be a debugging detail, rather than exposing
the user to it.

The problem is that if you do that, you might not notice that your limit
failed to work as expected. Maybe it's good enough in a case like this
that the user will see they tried to limit at 10000, but they only got
7135, so something must not have worked as expected.

Tatsuo: most of my tests were on Mac OS and Linux, I actually tested
the Mac version a lot more than any other here. I didn't do any testing
on Windows.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com