mysql的几个默认配置文件对比

在mysql的安装目录下的support-files目录里，有几份默认的配置参考文件（以mysql-5.1.56为例）
分别是 small,medium,large,huge 等，还有高压力的InnoDB的参考
key_buffer_size = 16K
key_buffer_size = 16M
key_buffer_size = 256M
key_buffer_size = 384M
myisam_sort_buffer_size = 8M
myisam_sort_buffer_size = 64M
myisam_sort_buffer_size = 64M
myisam_sort_buffer_size = 128M
query_cache_size= 16M
query_cache_size = 32M
query_cache_size = 64M
read_buffer_size = 256K
read_buffer_size = 1M
read_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 256K
read_rnd_buffer_size = 512K
read_rnd_buffer_size = 4M
read_rnd_buffer_size = 8M
read_rnd_buffer_size = 16M
sort_buffer_size = 64K
sort_buffer_size = 512K
sort_buffer_size = 1M
sort_buffer_size = 2M
sort_buffer_size = 8M
table_open_cache = 4
table_open_cache = 64
table_open_cache = 256
table_open_cache = 512
table_open_cache = 2048
一般的mysql配置优化，都是通过对以上的几个值进行的，具体操作时还得根据实际来操作

my-small.cnf
key_buffer_size = 16K
max_allowed_packet = 1M
table_open_cache = 4
sort_buffer_size = 64K
read_buffer_size = 256K
read_rnd_buffer_size = 256K
net_buffer_length = 2K
thread_stack = 128K
server-id       = 1
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 8M
sort_buffer_size = 8M

my-medium.cnf
key_buffer_size = 16M
max_allowed_packet = 1M
table_open_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
log-bin=mysql-bin
binlog_format=mixed
server-id       = 1
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M

my-large.cnf
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
thread_concurrency = 8
log-bin=mysql-bin
binlog_format=mixed
server-id       = 1
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

my-huge.cnf
key_buffer_size = 384M
max_allowed_packet = 1M
table_open_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size = 32M
thread_concurrency = 8
log-bin=mysql-bin
server-id       = 1
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

my-innodb-heavy-4G.cnf
back_log = 50
max_connections = 100
max_connect_errors = 10
table_open_cache = 2048
max_allowed_packet = 16M
binlog_cache_size = 1M
max_heap_table_size = 64M
read_buffer_size = 2M
read_rnd_buffer_size = 16M
sort_buffer_size = 8M
join_buffer_size = 8M
thread_cache_size = 8
thread_concurrency = 8
query_cache_size = 64M
query_cache_limit = 2M
ft_min_word_len = 4
default-storage-engine = MYISAM
thread_stack = 192K
transaction_isolation = REPEATABLE-READ
tmp_table_size = 64M
log-bin=mysql-bin
binlog_format=mixed
slow_query_log
long_query_time = 2
server-id = 1
key_buffer_size = 32M
bulk_insert_buffer_size = 64M
myisam_sort_buffer_size = 128M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1
myisam_recover
innodb_additional_mem_pool_size = 16M
innodb_buffer_pool_size = 2G
innodb_data_file_path = ibdata1:10M:autoextend
innodb_file_io_threads = 4
innodb_thread_concurrency = 16
innodb_flush_log_at_trx_commit = 1
innodb_log_buffer_size = 8M
innodb_log_file_size = 256M
innodb_log_files_in_group = 3
innodb_max_dirty_pages_pct = 90
innodb_lock_wait_timeout = 120
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
[myisamchk]
key_buffer_size = 512M
sort_buffer_size = 512M
read_buffer = 8M
write_buffer = 8M
[mysqlhotcopy]
interactive-timeout
[mysqld_safe]
open-files-limit = 8192