Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement) - Mailing list pgsql-hackers

From Greg Smith
Subject Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement)
Date
Msg-id 51E65BA8.6050907@2ndQuadrant.com
Whole thread Raw
In response to Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement)  (Tatsuo Ishii <ishii@postgresql.org>)
Responses Re: [PATCH] pgbench --throttle (submission 7 - with lag measurement)
List pgsql-hackers
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@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com



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