Mysql provides a configuration file located in /etc/my.cnf. From here you can set all of the memory, table, and connection limits as well as a host of other options. Before we get started I suggest you get aquainted with the my.cnf file as well as the tuning parameters within it.
Here is the my.cnf I use:
[mysqld]
back_log = 75
skip-innodb
max_connections = 500
key_buffer = 384M
myisam_sort_buffer_size = 64M
join_buffer_size = 1M
read_buffer_size = 1M
sort_buffer_size = 2M
table_cache = 1800
thread_cache_size = 384
wait_timeout = 7200
connect_timeout = 10
tmp_table_size = 64M
max_heap_table_size = 64M
max_allowed_packet = 64M
max_connect_errors = 1000
read_rnd_buffer_size = 524288
bulk_insert_buffer_size = 8M
query_cache_limit = 4M
query_cache_size =128M
query_cache_type = 1
query_prealloc_size = 65536
query_alloc_block_size = 131072
default-storage-engine = MyISAM
[mysqld_safe]
nice = -5
open_files_limit = 8192
[mysqldump]
quick
max_allowed_packet = 16M
[myisamchk]
key_buffer = 64M
sort_buffer = 64M
read_buffer = 16M
write_buffer = 16M
Let’s just look at the important bits.
max_connections = 500 – I use a tool (see below) to check how many current connections I have, and under very heavy load (2000 simultaneous users) I rarely hit 400 concurrent connections to the database. This is because most connections only last for a few milliseconds.
key_buffer = 384M - When tuning a MySQL server, key_buffer_size is very important. This number works well for me and with the mysqlreport script I rarely use 50% of the available memory.
