mysql tests - one more thing to try

[Mike Silbersack]

On Thu, 6 Apr 2006, Sven Petai wrote:

> On Wednesday 05 April 2006 21:52, Mike Silbersack wrote:
>
>> If you're willing to spend more time looking at this, I suggest that you
>> run truss or ktrace on the super-smack processes.  I did a small amount of
>> mysql vs postgres vs firebird benchmarking two years ago for a class
>> project, and noticed that mysql's results were showing the same phenomena
>> - our test program was using more cpu than mysqld.  I run truss on our
>> test program and found that it was doing ONE BYTE READS from the socket,
>> rather than something larger.
>>
>> I never had the time to see if the problem was fixed at a later time or
>> not.  You may wish to see if that same condition is still happening.
>
> here are ktrace results for supersmack and mysqld from a dualcore opteron box
> running select smack with 100 threads and 10000 queries
> os: fbsd 6.1 prerelease
>
> ==== syscall stats for supersmack ====
>
> request sizes for syscall read
>  size  count   %
> ---------------------------
>   4    15489977  47.06%
>   50    3982797  12.10%
>   1    3873493  11.77%
>   52    2654645  8.07%
>   60    1937753  5.89%
>   5    1933249  5.87%
>   8192    1931176  5.87%
>   53    790179  2.40%
>   51    274285  0.83%

<rest of info cut>

Thanks for running those tests, Sven.  It looks like the problem still 
exists. :(

I wish I had time to work on this...

Mike "Silby" Silbersack