Od
>bruce> Now for another question. It is possibly related the points above.
>bruce> What is the overhead of parsing a SQL query from a string into it's
>bruce> intermediate format (the format that the server uses to process
>bruce> the query)?
>
>MySQL has a very fast parser, but it's still and overhead. For most
>queries it's neglectable just because the query takes so long to
>execute, but for simple things it's can be up 1-10 % of the total
>time. Another win is that if the server can get the strings
>'unescaped', we can save memory as we don't need to save a copy of the
>unescaped string argument but can use a pointer to the original string!
>
You can get an idea of the parser speed + intialization overhead from the
following benchmark:
A single CPU Pentium 500 running Linux performs 6000 trivial ( SELECT 1)
queries per second. The same machine can perform 2800 indexed selects
returning one row of 25 bytes per second on a 2.8 MB table containing 45,000
rows. At some point, I want to break everything down and benchmark each
syscall and function individually to see how the time is distributed.
--
MySQL Development Team
__ ___ ___ ____ __
/ |/ /_ __/ __/ __ \/ / Sasha Pachev <sasha@stripped>
/ /|_/ / // /\ \/ /_/ / /__ MySQL AB, http://www.mysql.com/
/_/ /_/\_, /___/\___\_\___/ Provo, Utah, USA
<___/
