修正分頁、Too many connection 問題

lib/database-monitor.ts

@@ -0,0 +1,166 @@
+// =====================================================
+// 資料庫連線監控工具
+// =====================================================
+
+import { db } from './database';
+
+export class DatabaseMonitor {
+  private static instance: DatabaseMonitor;
+  private connectionCount = 0;
+  private maxConnections = 0;
+  private isMonitoring = false;
+  private monitorInterval: NodeJS.Timeout | null = null;
+
+  private constructor() {}
+
+  public static getInstance(): DatabaseMonitor {
+    if (!DatabaseMonitor.instance) {
+      DatabaseMonitor.instance = new DatabaseMonitor();
+    }
+    return DatabaseMonitor.instance;
+  }
+
+  // 開始監控
+  public startMonitoring(intervalMs: number = 30000) {
+    if (this.isMonitoring) {
+      console.log('⚠️ 資料庫監控已在運行中');
+      return;
+    }
+
+    this.isMonitoring = true;
+    console.log('🔍 開始監控資料庫連線狀態...');
+
+    this.monitorInterval = setInterval(async () => {
+      await this.checkConnectionStatus();
+    }, intervalMs);
+
+    // 立即執行一次檢查
+    this.checkConnectionStatus();
+  }
+
+  // 停止監控
+  public stopMonitoring() {
+    if (this.monitorInterval) {
+      clearInterval(this.monitorInterval);
+      this.monitorInterval = null;
+    }
+    this.isMonitoring = false;
+    console.log('⏹️ 資料庫監控已停止');
+  }
+
+  // 檢查連線狀態
+  private async checkConnectionStatus() {
+    try {
+      // 檢查當前連線數
+      const statusResult = await db.queryOne(`
+        SHOW STATUS LIKE 'Threads_connected'
+      `);
+      
+      const currentConnections = statusResult?.Value || 0;
+      this.connectionCount = parseInt(currentConnections);
+
+      // 檢查最大連線數
+      const maxConnResult = await db.queryOne(`
+        SHOW VARIABLES LIKE 'max_connections'
+      `);
+      
+      this.maxConnections = parseInt(maxConnResult?.Value || '100');
+
+      // 檢查連線使用率
+      const usagePercentage = (this.connectionCount / this.maxConnections) * 100;
+
+      // 記錄狀態
+      console.log(`📊 資料庫連線狀態: ${this.connectionCount}/${this.maxConnections} (${usagePercentage.toFixed(1)}%)`);
+
+      // 警告檢查
+      if (usagePercentage > 80) {
+        console.warn(`⚠️ 資料庫連線使用率過高: ${usagePercentage.toFixed(1)}%`);
+      } else if (usagePercentage > 60) {
+        console.log(`⚠️ 資料庫連線使用率較高: ${usagePercentage.toFixed(1)}%`);
+      }
+
+      // 檢查長時間運行的查詢
+      await this.checkLongRunningQueries();
+
+    } catch (error) {
+      console.error('❌ 資料庫監控錯誤:', error);
+    }
+  }
+
+  // 檢查長時間運行的查詢
+  private async checkLongRunningQueries() {
+    try {
+      const longQueries = await db.query(`
+        SELECT 
+          ID,
+          USER,
+          HOST,
+          DB,
+          COMMAND,
+          TIME,
+          STATE,
+          INFO
+        FROM information_schema.PROCESSLIST 
+        WHERE TIME > 30 
+        AND COMMAND != 'Sleep'
+        ORDER BY TIME DESC
+        LIMIT 5
+      `);
+
+      if (longQueries.length > 0) {
+        console.warn(`⚠️ 發現 ${longQueries.length} 個長時間運行的查詢:`);
+        longQueries.forEach((query, index) => {
+          console.warn(`  ${index + 1}. 用戶: ${query.USER}, 時間: ${query.TIME}s, 狀態: ${query.STATE}`);
+          if (query.INFO && query.INFO.length > 100) {
+            console.warn(`     查詢: ${query.INFO.substring(0, 100)}...`);
+          } else if (query.INFO) {
+            console.warn(`     查詢: ${query.INFO}`);
+          }
+        });
+      }
+    } catch (error) {
+      console.error('❌ 檢查長時間查詢時發生錯誤:', error);
+    }
+  }
+
+  // 獲取連線統計
+  public getConnectionStats() {
+    return {
+      currentConnections: this.connectionCount,
+      maxConnections: this.maxConnections,
+      usagePercentage: (this.connectionCount / this.maxConnections) * 100,
+      isMonitoring: this.isMonitoring
+    };
+  }
+
+  // 強制釋放空閒連線
+  public async releaseIdleConnections() {
+    try {
+      const result = await db.query(`
+        KILL 
+        (SELECT GROUP_CONCAT(ID) 
+         FROM information_schema.PROCESSLIST 
+         WHERE COMMAND = 'Sleep' 
+         AND TIME > 300)
+      `);
+      
+      console.log('🔄 已嘗試釋放空閒連線');
+      return true;
+    } catch (error) {
+      console.error('❌ 釋放空閒連線失敗:', error);
+      return false;
+    }
+  }
+
+  // 獲取連線池狀態
+  public getPoolStatus() {
+    // 這裡可以添加更多連線池狀態信息
+    return {
+      isMonitoring: this.isMonitoring,
+      lastCheck: new Date().toISOString()
+    };
+  }
+}
+
+// 導出單例實例
+export const dbMonitor = DatabaseMonitor.getInstance();