Re: pgbench tps drop from 5000 to 37 going from localhost to a server 13ms away

>> Am 24.07.2015 um 18:59 schrieb Chris Withers <chris(at)simplistix(dot)co(dot)uk>:
>>
>> Hi all,
>>
>> I've been doing some lightweight load testing with
>> “pgbench -c8 -j8 -T10”
>>
>> When run locally on the postgres server I've testing, this gives around 5000tps
>>
>> When I do it from a server that has a 13ms ping latency, it drops to 37tps.
>>
>> This is using the default pgbench script, is it to be expected?
>> If so, why?
>>

> Am 24.07.2015 um 20:06 schrieb Jan Lentfer <Jan(dot)Lentfer(at)web(dot)de>:
>
> That seems to be a large drop. On the other hand 13 ms is also like a very large network latency. On LAN your usually in the sub ms area. So going from e.g. 0.2 ms to 13ms is 65 fold decrease. What is the network toplogy like?
>

Sorry for top posting my first response. Always happens when I am on the iPad.
I just checked on my home setup. Ping latency on GBit crossover connection is around 0.3 ms, while pinging localhost is around 0.05 ms. You are at 13ms. So that is a 260 fold decrease, which is in about the same area as what you see with pgbench. Of course with pgbench the actual payload comes into account on top.

Jan