Initial commit: 宁夏智慧养殖监管平台

backend/config/query-optimizer.js

@@ -0,0 +1,246 @@
+/**
+ * 数据库查询优化器
+ * @file query-optimizer.js
+ * @description 监控和优化SQL查询性能
+ */
+const { sequelize } = require('./database-pool');
+const { QueryTypes } = require('sequelize');
+
+/**
+ * 记录查询性能
+ * @param {string} query SQL查询语句
+ * @param {number} executionTime 执行时间（毫秒）
+ * @returns {Promise<void>}
+ */
+async function logQueryPerformance(query, executionTime) {
+  try {
+    // 简化查询语句（移除参数值）
+    const simplifiedQuery = query.replace(/('([^']*)'|"([^"]*)"|`([^`]*)`)/g, '?');
+    
+    // 记录到性能日志表
+    await sequelize.query(
+      'INSERT INTO query_performance_logs (query, execution_time, timestamp) VALUES (?, ?, NOW())',
+      {
+        replacements: [simplifiedQuery, executionTime],
+        type: QueryTypes.INSERT
+      }
+    ).catch(() => {
+      // 如果表不存在，创建表
+      return sequelize.query(
+        `CREATE TABLE IF NOT EXISTS query_performance_logs (
+          id INT AUTO_INCREMENT PRIMARY KEY,
+          query TEXT NOT NULL,
+          execution_time FLOAT NOT NULL,
+          timestamp DATETIME NOT NULL,
+          INDEX (timestamp),
+          INDEX (execution_time)
+        )`,
+        { type: QueryTypes.RAW }
+      ).then(() => {
+        // 重新尝试插入
+        return sequelize.query(
+          'INSERT INTO query_performance_logs (query, execution_time, timestamp) VALUES (?, ?, NOW())',
+          {
+            replacements: [simplifiedQuery, executionTime],
+            type: QueryTypes.INSERT
+          }
+        );
+      });
+    });
+  } catch (error) {
+    console.error('记录查询性能失败:', error);
+  }
+}
+
+/**
+ * 识别慢查询
+ * @param {number} threshold 慢查询阈值（毫秒），默认为500ms
+ * @returns {Promise<Array>} 慢查询列表
+ */
+async function identifySlowQueries(threshold = 500) {
+  try {
+    // 查询性能日志表中的慢查询
+    const slowQueries = await sequelize.query(
+      'SELECT query, AVG(execution_time) as avg_time, COUNT(*) as count, MAX(timestamp) as last_seen ' +
+      'FROM query_performance_logs ' +
+      'WHERE execution_time > ? ' +
+      'GROUP BY query ' +
+      'ORDER BY avg_time DESC',
+      {
+        replacements: [threshold],
+        type: QueryTypes.SELECT
+      }
+    ).catch(() => {
+      // 如果表不存在，返回空数组
+      return [];
+    });
+    
+    return slowQueries;
+  } catch (error) {
+    console.error('识别慢查询失败:', error);
+    return [];
+  }
+}
+
+/**
+ * 分析和优化表
+ * @param {string} tableName 表名
+ * @returns {Promise<Object>} 优化结果
+ */
+async function analyzeAndOptimizeTable(tableName) {
+  try {
+    // 分析表
+    await sequelize.query(`ANALYZE TABLE ${tableName}`, { type: QueryTypes.RAW });
+    
+    // 优化表
+    const optimizeResult = await sequelize.query(`OPTIMIZE TABLE ${tableName}`, { type: QueryTypes.RAW });
+    
+    return optimizeResult[0];
+  } catch (error) {
+    console.error(`分析和优化表 ${tableName} 失败:`, error);
+    return { error: error.message };
+  }
+}
+
+/**
+ * 获取表的索引信息
+ * @param {string} tableName 表名
+ * @returns {Promise<Array>} 索引信息
+ */
+async function getIndexInfo(tableName) {
+  try {
+    const indexInfo = await sequelize.query(
+      'SHOW INDEX FROM ??',
+      {
+        replacements: [tableName],
+        type: QueryTypes.SELECT
+      }
+    );
+    
+    return indexInfo;
+  } catch (error) {
+    console.error(`获取表 ${tableName} 的索引信息失败:`, error);
+    return [];
+  }
+}
+
+/**
+ * 获取表信息
+ * @param {string} tableName 表名
+ * @returns {Promise<Object>} 表信息
+ */
+async function getTableInfo(tableName) {
+  try {
+    // 获取表状态
+    const tableStatus = await sequelize.query(
+      'SHOW TABLE STATUS LIKE ?',
+      {
+        replacements: [tableName],
+        type: QueryTypes.SELECT
+      }
+    );
+    
+    // 获取表结构
+    const tableStructure = await sequelize.query(
+      'DESCRIBE ??',
+      {
+        replacements: [tableName],
+        type: QueryTypes.SELECT
+      }
+    );
+    
+    return {
+      status: tableStatus[0] || {},
+      structure: tableStructure
+    };
+  } catch (error) {
+    console.error(`获取表 ${tableName} 信息失败:`, error);
+    return { error: error.message };
+  }
+}
+
+/**
+ * 解释查询计划
+ * @param {Object} query Sequelize查询对象
+ * @returns {Promise<Array>} 查询计划
+ */
+async function explainQuery(query) {
+  try {
+    // 获取SQL语句
+    const sql = query.getQueryString();
+    
+    // 执行EXPLAIN
+    const explainResult = await sequelize.query(
+      `EXPLAIN ${sql}`,
+      {
+        type: QueryTypes.SELECT
+      }
+    );
+    
+    return explainResult;
+  } catch (error) {
+    console.error('解释查询计划失败:', error);
+    return [];
+  }
+}
+
+/**
+ * 获取数据库状态
+ * @returns {Promise<Object>} 数据库状态
+ */
+async function getDatabaseStatus() {
+  try {
+    // 获取全局状态
+    const globalStatus = await sequelize.query(
+      'SHOW GLOBAL STATUS',
+      { type: QueryTypes.SELECT }
+    );
+    
+    // 转换为对象格式
+    const status = {};
+    globalStatus.forEach(item => {
+      if (item.Variable_name && item.Value) {
+        status[item.Variable_name] = item.Value;
+      }
+    });
+    
+    // 提取关键指标
+    return {
+      connections: {
+        max_used: status.Max_used_connections,
+        current: status.Threads_connected,
+        running: status.Threads_running,
+        created: status.Threads_created,
+        cached: status.Threads_cached
+      },
+      queries: {
+        total: status.Questions,
+        slow: status.Slow_queries,
+        qps: status.Queries
+      },
+      buffer_pool: {
+        size: status.Innodb_buffer_pool_pages_total,
+        free: status.Innodb_buffer_pool_pages_free,
+        dirty: status.Innodb_buffer_pool_pages_dirty,
+        reads: status.Innodb_buffer_pool_reads,
+        read_requests: status.Innodb_buffer_pool_read_requests,
+        hit_rate: status.Innodb_buffer_pool_read_requests && status.Innodb_buffer_pool_reads
+          ? (1 - parseInt(status.Innodb_buffer_pool_reads) / parseInt(status.Innodb_buffer_pool_read_requests)) * 100
+          : 0
+      }
+    };
+  } catch (error) {
+    console.error('获取数据库状态失败:', error);
+    return { error: error.message };
+  }
+}
+
+module.exports = {
+  logQueryPerformance,
+  identifySlowQueries,
+  analyzeAndOptimizeTable,
+  getIndexInfo,
+  getTableInfo,
+  explainQuery,
+  getDatabaseStatus
+};