mysql 5.6 优化参数减少内存占用 mysql 5.6默认启动占用内存400多M，如果是vps等小内存应用，mysql内存占用率明显偏高,将会导致崩溃，mysql会自动停止。 编辑/etc/my.cnf文件在[mysqld]下增加或修改如下参数 performance_schema_max_table_instances = 200 table_definition_cache = 100 table_open_cache = 100 这个三个参数，调低值后内存能明显减小，现在mysql使用内存约60MB左右，就大大降低默认使用的内存。 进一步调整参数 innodb_buffer_pool_size=2M 这个三个参数可以调小。 再进一步调整： mysql 5.6默认启用performance_schema，占用很多内存，可以禁用。 完整配置文件如下，内存占用到22M 我的mysql配置如下，如果你使用的centos6 64位，并且是yum安装的（一键脚本)可以自己按照如下照抄，我的是centos6 64位系统 先ssh登录服务器或VPS，执行 命令: vi /etc/my.cnf # For advice on how to change settings please see # http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html [mysqld] # # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M # # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin # # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock #symbolic-links=0 skip-external-locking key_buffer_size = 8M 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 = 240K #innodb_use_native_aio = 0 innodb_buffer_pool_size=2M performance_schema_max_table_instances=50 table_definition_cache=50 table_open_cache=32 max_connections=50 max_user_connections=35 wait_timeout=10 interactive_timeout=15 long_query_time=5 # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 # Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid 默认值如下： performance_schema_max_table_instances 12500 table_definition_cache 1400 table_open_cache 2000 参数含义 performance_schema_max_table_instance The maximum number of instrumented table objects. table_definition_cache The number of table definitions (from .frm files) that can be stored in the definition cache table_open_cache The number of open tables for all threads 翻译: 已检测到的最大表对象数。 Table_definition_cache 可以存储在已定义的缓存table_open_cache中的表定义（来自.frm文件）的数量 所有线程的打开表数