MyISAM not scaling well

[James Brown]

Hi all,

I have one MySQL server in one node and I will use other nodes as clients to forward queries in a flow style. Each client node will forward one query after the other. The question is, how will the server behave when increasing the number of concurrent query flows?

I expected that MySQL will scale at least a few concurrent flows, but the number of queries per time does not increase when increasing the number of flows.

System description:
4 quad-core Opteron (16 cores total), 8GB RAM. MySQL 5.1.
Queries are short (some milliseconds) and read-only.
Tables: around 80GB, MyISAM, stored in a SSD.
I tried with different key_buffer_size and read_buffer_size but no differences.
Max_connections is set to 1024.

When I launch 2 query flows, I can see them when doing "show processlist", and are being executed. The CPU usage is quite low, around 20%. And the query per time metric is the same as using only 1 query flow.

Any idea? Is there any documentation about testing MyISAM with several threads and short read-only queries?

Thanks in advance!