求助！mysql服务器占用cpu过高

[canxuegigi]

show processlist 时，状态是 statistics 的线程很多，这个要怎么解决呢

还有就是导致mysql占用资源过多的一般原因有哪些

谢谢！！！

[canxuegigi]

引用 1 楼 weiwangwang521 的回复:

其实这是 mysql 配置上的问题， 默认的 linux 中， mysql 的配置是 my-large.cnf 配置，该配置适合大型服务器。有高内存，比如2G，4G内存的，适合使用，而一般512M内存 的就不行了。它会占用512M内存来保存系统 mysql 的进程，这些进程长期堆质，并不释放，导致系统缓慢。所以，把配置改变成为 my-small.cnf ，小型配置就可以了。它的配置如下： # Example mysql config file for small systems. # # This is for a system with little memory (<= 64M) where MySQL is only used # from time to time and it's important that the mysqld deamon # doesn't use much resources. # # You can copy this file to # /etc/my.cnf to set global options, # mysql-data-dir/my.cnf to set server-specific options (in this # installation this directory is /var/lib/mysql) or # ~/.my.cnf to set user-specific options. # # One can in this file use all long options that the program supports. # If you want to know which options a program support, run the program # with --help option. # The following options will be passed to all MySQL clients [client] #password = 你的密码 port = 3306 socket = /tmp/mysql.sock # Here follows entries for some specific programs # The MySQL server [mysqld] port = 3306 socket = /tmp/mysql.sock skip-locking set-variable = key_buffer=16K set-variable = max_allowed_packet=1M set-variable = thread_stack=64K set-variable = table_cache=4 set-variable = sort_buffer=64K set-variable = net_buffer_length=2K server-id = 1 # Uncomment the following if you want to log updates #log-bin # Uncomment the following if you are NOT using BDB tables #skip-bdb # Uncomment the following if you are using InnoDB tables #innodb_data_home_dir = /var/lib/mysql/ #innodb_data_file_path = ibdata1:10M:autoextend #innodb_log_group_home_dir = /var/lib/mysql/ #innodb_log_arch_dir = /var/lib/mysql/ # You can set .._buffer_pool_size up to 50 - 80 % # of RAM but beware of setting memory usage too high #set-variable = innodb_buffer_pool_size=16M #set-variable = innodb_additional_mem_pool_size=2M # Set .._log_file_size to 25 % of buffer pool size #set-variable = innodb_log_file_size=5M #set-variable = innodb_log_buffer_size=8M #innodb_flush_log_at_trx_commit=1 #set-variable = innodb_lock_wait_timeout=50 [mysqldump] quick set-variable = max_allowed_packet=16M [mysql] no-auto-rehash # Remove the next comment character if you are not familiar with SQL #safe-updates [isamchk] set-variable = key_buffer=8M set-variable = sort_buffer=8M [myisamchk] set-variable = key_buffer=8M set-variable = sort_buffer=8M [mysqlhotcopy] interactive-timeout

那个应该不是配置文件的问题，只是针对有些sql ，一运行就是长时间的 statistics，但那些sql也是简单的select、

[canxuegigi]

引用 2 楼 lisong526 的回复:

手册上是这么说的： statistics The server is calculating statistics to develop a query execution plan.

这个我也知道、

[weiwangwang521]

其实这是 mysql 配置上的问题， 默认的 linux 中， mysql 的配置是 my-large.cnf 配置，该配置适合大型服务器。有高内存，比如2G，4G内存的，适合使用，而一般512M内存 的就不行了。它会占用512M内存来保存系统 mysql 的进程，这些进程长期堆质，并不释放，导致系统缓慢。所以，把配置改变成为 my-small.cnf ，小型配置就可以了。它的配置如下： # Example mysql config file for small systems. # # This is for a system with little memory (<= 64M) where MySQL is only used # from time to time and it's important that the mysqld deamon # doesn't use much resources. # # You can copy this file to # /etc/my.cnf to set global options, # mysql-data-dir/my.cnf to set server-specific options (in this # installation this directory is /var/lib/mysql) or # ~/.my.cnf to set user-specific options. # # One can in this file use all long options that the program supports. # If you want to know which options a program support, run the program # with --help option. # The following options will be passed to all MySQL clients [client] #password = 你的密码 port = 3306 socket = /tmp/mysql.sock # Here follows entries for some specific programs # The MySQL server [mysqld] port = 3306 socket = /tmp/mysql.sock skip-locking set-variable = key_buffer=16K set-variable = max_allowed_packet=1M set-variable = thread_stack=64K set-variable = table_cache=4 set-variable = sort_buffer=64K set-variable = net_buffer_length=2K server-id = 1 # Uncomment the following if you want to log updates #log-bin # Uncomment the following if you are NOT using BDB tables #skip-bdb # Uncomment the following if you are using InnoDB tables #innodb_data_home_dir = /var/lib/mysql/ #innodb_data_file_path = ibdata1:10M:autoextend #innodb_log_group_home_dir = /var/lib/mysql/ #innodb_log_arch_dir = /var/lib/mysql/ # You can set .._buffer_pool_size up to 50 - 80 % # of RAM but beware of setting memory usage too high #set-variable = innodb_buffer_pool_size=16M #set-variable = innodb_additional_mem_pool_size=2M # Set .._log_file_size to 25 % of buffer pool size #set-variable = innodb_log_file_size=5M #set-variable = innodb_log_buffer_size=8M #innodb_flush_log_at_trx_commit=1 #set-variable = innodb_lock_wait_timeout=50 [mysqldump] quick set-variable = max_allowed_packet=16M [mysql] no-auto-rehash # Remove the next comment character if you are not familiar with SQL #safe-updates [isamchk] set-variable = key_buffer=8M set-variable = sort_buffer=8M [myisamchk] set-variable = key_buffer=8M set-variable = sort_buffer=8M [mysqlhotcopy] interactive-timeout

[嘟嘟xo]

手册上是这么说的： statistics The server is calculating statistics to develop a query execution plan.