MySQL: ERROR 1040: Too many connections”異常情況處理
經常會遇到”MySQL: ERROR 1040: Too many connections”的異常情況，很多時原因是使用了預設最大連線數或設定過少
檢視目前最大連線數
mysql> show variables like '%max_connections%';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 300 |
+-----------------+-------+
1 row in set (0.00 sec)
方法1：使用set GLOBAL max_connections
mysql> set GLOBAL max_connections=3000;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like '%max_connections%';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 3000 |
+-----------------+-------+
1 row in set (0.00 sec)
方案2:在mysql配置檔案新增或修改max_connections值
vim /etc/mysql/mysql.conf.d/mysqld.cnf
max_connections=3000
此方案需重啟mysql服務
注意：重啟後最大連線數有可能還是214，需修改檔案/lib/systemd/system/mysql.service新增
LimitNOFILE=65535
LimitNPROC=65535
儲存後重啟mysql服務即可生效
systemctl daemon-reload
systemctl restart mysql.service