-- 查看当前所有连接的详细信息
SHOW PROCESSLIST;

-- 只查看连接总数（包括睡眠状态的连接）
SELECT COUNT(*) AS total_connections FROM information_schema.processlist;

-- 查看不同状态的连接数统计
SELECT 
  STATE, 
  COUNT(*) AS connection_count 
FROM 
  information_schema.processlist 
GROUP BY 
  STATE 
ORDER BY 
  connection_count DESC;

-- 查看最大连接数设置
SHOW VARIABLES LIKE 'max_connections';

-- 查看已使用的连接数和最大连接数的比例
SELECT 
  CONCAT(ROUND((Threads_connected / max_connections) * 100, 2), '%') AS connection_usage 
FROM 
  status, 
  variables 
WHERE 
  status.Variable_name = 'Threads_connected' 
  AND variables.Variable_name = 'max_connections';