mysql - 计算mysql最大连接数限制

Question

在高峰时段遇到性能问题，导致 MYSQL 无法响应。试图弄清楚我是否使用了正确的最大连接值。服务器有 64GB RAM。

+------------------------------+------------+
| Variable_name                | Value      |
+------------------------------+------------+
| bulk_insert_buffer_size      | 8388608    |
| innodb_buffer_pool_instances | 1          |
| innodb_buffer_pool_size      | 134217728  |
| innodb_change_buffering      | all        |
| innodb_log_buffer_size       | 8388608    |
| join_buffer_size             | 67108864   |
| key_buffer_size              | 2147483648 |
| myisam_sort_buffer_size      | 8388608    |
| net_buffer_length            | 16384      |
| preload_buffer_size          | 32768      |
| read_buffer_size             | 67108864   |
| read_rnd_buffer_size         | 2097152    |
| sort_buffer_size             | 2097152    |
| sql_buffer_result            | OFF        |
+------------------------------+------------+

lsof | wc -l
124101

lsof -a -p MYSQLDPID | wc -l
518

mysql> SHOW STATUS LIKE '%connection%';
+----------------------+----------+
| Variable_name        | Value    |
+----------------------+----------+
| Connections          | 25019772 |
| Max_used_connections | 451      |
+----------------------+----------+

当前连接限制设置为 350。我还需要哪些其他变量来计算正确的连接限制？

Answer 1

查看 STATUS 变量。 Connections 和 Max_used_connections 会显示服务器已使用的连接数。

SHOW STATUS LIKE '%connection%';

Variable_name   Value
Connection_errors_accept    0
Connection_errors_internal  0
Connection_errors_max_connections   0
Connection_errors_peer_address  0
Connection_errors_select    0
Connection_errors_tcpwrap   0
Connections 13
Max_used_connections    7