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Re: Extreme high load and low throughput using MySQL & Hybris on an HP DL380G5, quad-core Intel, 4GB RAM
Posted by: Aftab Khan
Date: March 19, 2009 09:10AM

Your mysql is running with ~400 connections, with your
settings mysql will use approximately:

Per thread ram usage : (your my.cnf shows)
thread_stack (192K),
net_buffer_length (default),
read_buffer_size (2M),
read_rnd_buffer_size (16M ),
sort_buffer_size (16M )

Arround 33M per Thread
12.89063 GB RAM is required (with approximatly 400 active threads).

Note: Each thread connecting to MySQL server will needs its own memory to work with.
Thread stack is the amount of stack each thread will consume.
You can read more about stack here:
http://en.wikipedia.org/wiki/Stack_(data_structure)

When Query Cache is ON then most of the above per Thread connection variables are not used/required.

you have enabled slow log
Question
1. Explain Select ...# for all slow queries
2. Show Create Table ... # for all tables involved.
3. show table status ... # for all tables involved.

try to reduce the values of

read_rnd_buffer_size (16M ),
sort_buffer_size (16M )

you can increase their values for a particualr case(s) i.e. per session



Edited 2 time(s). Last edit at 03/19/2009 09:16AM by Aftab Khan.

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Re: Extreme high load and low throughput using MySQL & Hybris on an HP DL380G5, quad-core Intel, 4GB RAM
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