pgbench results

[Mark Kirkwood]

Mark Kirkwood wrote:
> Ivan Voras wrote:
>>
>> The thing is - I *do* have a similar setup here: HP DL370 G5, 2x4-core
>> 1.86 GHz, 4 GB RAM, 6 drives in RAID10, 512 MB cache (can pull > 200
>> MB/s off the array), with all settings like in the posted link except
>> shared_buffer=1900 MB, and I "only" get this:
>>
>> tps = 2834.026175 (including connections establishing)
>> tps = 2839.080739 (excluding connections establishing)
>>
>> This is still far bellow ~~ 4500 trans/s from the link and I wonder if
>> my results are within what I should be getting. The benchmark in the
>> link above was done with faster CPUs (but I'm not CPU bound - at least
>> 30% idle), but with 3 times the memory and I'm guessing more memory
>> would help here, but I'm not sure.
>>
>> What's strange is that toggling synchronous_commit doesn't have a
>> significant effect on performance (it does increase CPU idle time). With
>> synchronous_commit=off, I get:
>>
>> tps = 2886.980477 (including connections establishing)
>> tps = 2891.776081 (excluding connections establishing)
>>
>>   
>
> The article refers to a controller with a battery backed write cache - 
> that could easily explain the difference if you do not have one (he's 
> paying nothing for fsync wheres you are).
>

Hmm - somehow read right past the bit where you say you have a 512MB 
cache - sorry! However, worth checking it is set to write-back rather 
than write-through.

Cheers

Mark