参数优化案例：
1、服务器16G内存，峰值最大连接数为500个，使用MyISAM和InnoDB两种引擎。
为操作系统预留20%内存，约3G
2、与线程相关的几个关键参数
sort_buffer_size=2M
read_buffer_size=2M
read_rnd_buffer_size=2M
join_buffer_size=2M
峰值最大将占用500*(2+2+2+2)=4G
3、MyISAM引擎表不多，主要是系统对象
key_buffer_size=16M
key_cache_block_size=64K
myisam_sort_buffer_size=64M
4、剩下的全部分给InnoDB缓存池
innodb_buffer_pool_size=9G
innodb_thread_concurrency=8
innodb_flush_method=O_DIRECT
innodb_log_buffer_size=16M
innodb_flush_log_at_trx_commit=2
经过配置后，MySQL初始化参数文件为
[mysql@mysql1 3306]$ more my.cnf
[client]
port = 3306
socket = /data/mysqldata/3306/mysql.sock
#The MySQL server
[mysqld]
port = 3306
user = mysql
socket = /data/mysqldata/3306/mysql.sock
pid-file = /data/mysqldata/3306/mysql.pid
basedir = /usr/local/mysql
datadir = /data/mysqldata/3306/data
tmpdir = /data/mysqldata/3306/tmp
open_files_limit = 10240
explicit_defaults_for_timestamp
sql_mode = NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
federated
server_id=1223344556
max_connections = 1000
max_connect_errors = 100000
interactive_timeout = 86400
wait_timeout = 86400
skip-name-resolve
sync_binlog = 0
#Buffer
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 2M
join_buffer_size = 2M
net_buffer_length = 16K
max_allowed_packet = 512M
max_heap_table_size = 512M
bulk_insert_buffer_size = 32M
tmp_table_size = 512M
thread_cache_size = 300
query_cache_size = 128M
query_cache_limit = 1M
query_cache_min_res_unit = 4K
key_buffer_size = 16M
myisam_sort_buffer_size = 64M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1
#Log
log-bin = /data/mysqldata/3306/binlog/mysql-bin
binlog_cache_size = 32M
max_binlog_cache_size = 512M
max_binlog_size = 512M
#binlog_format = mixed
binlog_stmt_cache_size = 32M
table_open_cache = 2048
binlog_format = statement
log_output = FILE
log-error = /data/mysqldata/3306/mysql-error.log
slow_query_log = 1
slow_query_log_file = /data/mysqldata/3306/slow_query.log
general_log = 0
general_log_file = /data/mysqldata/3306/general_query.log
expire-logs-days = 14
relay-lay = /data/mysqldata/3306/binlog/relay-bin
relay-log-index = /data/mysqldata/3306/binlog/relay-bin.index
#InnoDB
innodb_data_file_path = ibdata1:2048M:autoextend
innodb_log_file_size = 256M
innodb_log_files_in_group = 3
innodb_buffer_pool_size = 9G
innodb_buffer_pool_instances = -1
innodb_max_dirty_pages_pct = 70
innodb_thread_concurrency = 8
innodb_flush_method = O_DIRECT
innodb_log_buffer_size = 16M
innodb_flush_log_at_trx_commit = 2
[mysql]
no-auto-rehash
prompt = (\u@\h) [\d]>\_
default-character-set = gbk
重新测试性能：
[mysql@mysql1 ~]$ /tpcc-mysql/tpcc_start -h localhost -d tpcc -u system -p "123456" -w 1 -c 10 -r 10 -l 20 -f /home/mysql/tpcc_mysql.log -t /home/mysql/tpcc_mysql.rtx