mysql性能调优

1、检查并设置连接限制
mysql> SHOW VARIABLES LIKE ‘max_connections‘;
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 151   |
+-----------------+-------+
1 row in set (0.00 sec)

#MySQL 的文档指出，健壮的服务器应该能够处理成百上千的连接数。“常规情况下，Linux 或 Solaris 应该能够支持 500 到 1000 个同时连接。如果可用的 RAM 较大，且每个连接的工作量较低或目标响应时间较为宽松，则最多可处理 10000 个连接。而 Windows 能处理的连接数一般不超过 2048 个，这是由于该平台上使用的 Posix 兼容层。”

#可以在系统运行时，调整连接数限制
mysql> SET GLOBAL max_connections = 200;
Query OK, 0 rows affected (0.00 sec)

#如果想永久生效，在my.cnf配置文件中设置
max_connections = 200
　　

mysql> SHOW GLOBAL VARIABLES LIKE "innodb_buffer_pool_size";
+-------------------------+---------+
| Variable_name           | Value   |
+-------------------------+---------+
| innodb_buffer_pool_size | 8388608 |
+-------------------------+---------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES LIKE "innodb_page_size";
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| innodb_page_size | 16384 |
+------------------+-------+
1 row in set (0.00 sec)

mysql> SHOW GLOBAL VARIABLES LIKE "innodb_buffer_pool_instances";
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| innodb_buffer_pool_instances | 8     |
+------------------------------+-------+
1 row in set (0.00 sec)