方便更快捷的说明问题，可以按需填写（可删除）
使用环境：
5.5.30-ShardingSphere-Proxy 5.3.0
场景、问题：
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
17282 root 20 0 28.4g 2.6g 23108 S 735.0 0.7 236:27.05 java
27352 mysql 20 0 36.5g 5.7g 13176 S 34.0 1.5 37384:04 mysqld
偶尔会增加到 4344%及以上
后端数据库负载很低，当CPU很高时，从SSP登录及任何查询 延迟均很大
mysql> select count(*) from xxxx;
+----------+
| count(*) |
+----------+
| 1008 |
+----------+
1 row in set (4.39 sec)
现导致业务超时异常频率增加
已进行操作：
重启后持续几分钟内正常，CPU逐渐增加，且延迟增加
现状：
mysql> SHOW DIST VARIABLES;
+---------------------------------------+----------------+
| variable_name | variable_value |
+---------------------------------------+----------------+
| sql_show | false |
| sql_simple | false |
| kernel_executor_size | 0 |
| max_connections_size_per_query | 1 |
| check_table_metadata_enabled | false |
| sql_federation_type | NONE |
| proxy_frontend_database_protocol_type | |
| proxy_frontend_flush_threshold | 128 |
| proxy_hint_enabled | false |
| proxy_backend_query_fetch_size | -1 |
| proxy_frontend_executor_size | 0 |
| proxy_backend_executor_suitable | OLAP |
| proxy_frontend_max_connections | 0 |
| proxy_backend_driver_type | JDBC |
| proxy_mysql_default_version | 5.7.22 |
| proxy_default_port | 8066 |
| proxy_netty_backlog | 1024 |
| proxy_instance_type | Proxy |
| agent_plugins_enabled | true |
| cached_connections | 0 |
| transaction_type | LOCAL |
+---------------------------------------+----------------+
21 rows in set (0.00 sec)