Temp mysql files jamming CPU resources (1 reply)

Dear Friends

I run my website "www.egully.com" on a dedicated server with a config of memory 8GB and 8GB RAM
the CPU load average often shoots from 2-3 to 20-30 and the site becomes extremely slow. On investigation we found a lot of temporary mysql tables are been created which is taking up lot of CPU resource. The temp tables are like :
/var/tmp/#sql_25dd_0.MYD
/var/tmp/#sql_25dd_1.MYD
/var/lib/mysql/egully1_cpdata2009/isc_product_search.MYD
/var/lib/mysql/egully1_cpdata2009/isc_product_search.MYD
/var/lib/mysql/egully1_cpdata2009/isc_product_search.MYD
/var/lib/mysql/egully1_cpdata2009/isc_product_search.MYD
/var/lib/mysql/egully1_cpdata2009/isc_product_search.MYI

These files are in order of 0.5-2.5GB.
After restarting mysql all the temp files gets deleted and system gets back to normal. But, after some time the problem again resurfaces.

I doubt if there is some problem with my.cnf file setting. Our current settings are
[mysqld]
set-variable = max_connections=200
socket = /var/lib/mysql/mysql.sock
key_buffer =512M
table_cache = 1024
open_files_limit = 16344
join_buffer_size = 32M
read_buffer_size = 32M
sort_buffer_size = 32M
tmp_table_size=256M
read_rnd_buffer_size=16M
max_heap_table_size=256M
myisam_sort_buffer_size=256M
thread_cache_size=8
thread_cache=8192
query_cache_type=1
query_cache_limit=256M
query_cache_size=256M
thread_concurrency=8
wait_timeout = 30
connect_timeout = 30
interactive_timeout = 60
long_query_time=1
log-slow-queries = /var/log/slowqueries.log
max_allowed_packet=128M


Can some one suggest what I need to do for improving the speed and avoid creation of the temp files