Which version of the libraries do you use (4.0, 4.1, 5.0)?
This has been fixed in recent versions of 5.0, and applications that fetch a
lot rows spend much less time in MySQL code.
On 4/1/07, Joseph Benden <joe@stripped> wrote:
>
> Hello,
>
> I cannot find anyone mentioning this elsewhere on the web or this list
> so I was wondering...
>
> I'm trying to squeeze all the performance possible from every piece of
> my Solaris systems. The last piece that is bugging me is the high
> number of system calls experienced on the machines. In analyzing the
> web server, I found the problem was the read() system call. Next, I
> wanted to know what sizes were being read and where from. It turns out
> the read()s are from the mysqlclient library and are 4 byte reads.
>
> value ------------- Distribution ------------- count
> 0 | 0
> 1 |@@@@@ 3447
> 2 |@ 616
> 4 |@@@@@@@@@@@@@@@@@@@ 12531
> 8 |@ 626
> 16 |@@@@@@@@ 4966
> 32 |@@ 1158
> 64 | 153
> 128 | 29
> 256 | 15
> 512 | 5
> 1024 | 17
> 2048 | 0
> 4096 | 0
> 8192 |@@@@ 2667
> 16384 | 0
>
>
> Upon further research with dtrace, I've found these read()s to
> correspond with the MySQL protocol packet header being read().
>
> I was wondering why a buffered approach wasn't taken. ie: A general
> buffered read() of everything possible from the wire and the protocol
> code asking for the number of bytes from that buffered area. I feel that
> in doing this many system calls could be reduced, which would increase
> the speed of using the library.
>
> Comments, suggestions, ideas? Thanks,
> -Joseph Benden
> Thralling Penguin LLC
>
>
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>
--
Mark Callaghan
mcallaghan@stripped
