feat(record): 添加物联网数据采样查询功能

- 在 RecordIotenvInstant 模型中添加 samplingInterval 字段
- 在 RecordIotenvInstantMapper 中添加采样查询方法
- 在 RecordIotenvInstantServiceImpl 中实现采样查询逻辑
- 通过分段+聚合的方式提高查询性能，适用于大量数据场景

os-ems/src/main/java/com/os/ems/record/domain/RecordIotenvInstant.java

@@ -90,6 +90,8 @@ public class RecordIotenvInstant extends BaseEntity
     private Long monitorType;
     private String energyName;
     
+    /** 采样间隔（分钟），用于数据抽稀 */
+    private Integer samplingInterval;
 
 //
 //    public void setObjid(Long objid)

os-ems/src/main/java/com/os/ems/record/mapper/RecordIotenvInstantMapper.java

@@ -154,4 +154,15 @@ public interface RecordIotenvInstantMapper
      */
     public List<RecordIotenvInstant> selectLatestRecordsByMonitorIdsFromTable(@Param("tableName") String tableName, 
                                                                                @Param("monitorIds") List<String> monitorIds);
+    
+    /**
+     * 按时间间隔采样查询：每个时间窗口选择最新的一条数据
+     * 用于减少数据点数量，提升前端渲染性能
+     * 
+     * @param tableNames 表名列表
+     * @param recordIotenvInstant 查询条件（包含samplingInterval采样间隔）
+     * @return 采样后的物联网数据集合
+     */
+    List<RecordIotenvInstant> selectRecordIotenvInstantListFromTablesWithSampling(@Param("tableNames") List<String> tableNames,
+                                                                                  @Param("recordIotenvInstant") RecordIotenvInstant recordIotenvInstant);
 }

os-ems/src/main/java/com/os/ems/record/service/impl/RecordIotenvInstantServiceImpl.java

@@ -72,8 +72,15 @@ public class RecordIotenvInstantServiceImpl implements IRecordIotenvInstantServi
                 if (tableNames.isEmpty()) {
                     return new ArrayList<>();
                 }
-                // 执行分表查询
-                return recordIotenvInstantMapper.selectRecordIotenvInstantListFromTables(tableNames, recordIotenvInstant);
+                
+                // 检查是否需要采样
+                if (recordIotenvInstant.getSamplingInterval() != null && recordIotenvInstant.getSamplingInterval() > 1) {
+                    // 使用采样查询
+                    return recordIotenvInstantMapper.selectRecordIotenvInstantListFromTablesWithSampling(tableNames, recordIotenvInstant);
+                } else {
+                    // 使用普通查询
+                    return recordIotenvInstantMapper.selectRecordIotenvInstantListFromTables(tableNames, recordIotenvInstant);
+                }
     }
 
     /**

os-ems/src/main/resources/mapper/ems/record/RecordIotenvInstantMapper.xml

@@ -366,4 +366,43 @@ PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
         ) t2 ON t1.monitorId = t2.monitorId AND t1.objid = t2.max_objid
     </select>
 
+    <!-- 高性能采样查询：TiDB原生优化，无索引依赖 -->
+    <select id="selectRecordIotenvInstantListFromTablesWithSampling" resultMap="RecordIotenvInstantResult">
+        <!-- 使用分段+聚合的高效算法，避免复杂窗口函数 -->
+        <foreach collection="tableNames" item="tableName" separator=" UNION ALL ">
+            SELECT 
+                t1.objid, t1.monitorId, t1.temperature, t1.humidity, t1.illuminance, t1.noise, t1.concentration,
+                t1.vibration_speed, t1.vibration_displacement, t1.vibration_acceleration, t1.vibration_temp,
+                t1.collectTime, t1.recodeTime
+            FROM ${tableName} t1
+            INNER JOIN (
+                SELECT 
+                    monitorId,
+                    FLOOR(UNIX_TIMESTAMP(recodeTime) / (#{recordIotenvInstant.samplingInterval} * 60)) as time_slot,
+                    MAX(recodeTime) as max_time
+                FROM ${tableName}
+                <where>
+                    <if test="recordIotenvInstant.monitorId != null and recordIotenvInstant.monitorId != ''">
+                        AND monitorId = #{recordIotenvInstant.monitorId}
+                    </if>
+                    <if test="recordIotenvInstant.params.beginRecordTime != null and recordIotenvInstant.params.endRecordTime != null">
+                        AND recodeTime &gt;= #{recordIotenvInstant.params.beginRecordTime}
+                        AND recodeTime &lt;= #{recordIotenvInstant.params.endRecordTime}
+                    </if>
+                    <if test="recordIotenvInstant.monitorIds != null and recordIotenvInstant.monitorIds.length > 0">
+                        AND monitorId IN
+                        <foreach collection="recordIotenvInstant.monitorIds" item="monitorId" open="(" separator="," close=")">
+                            #{monitorId}
+                        </foreach>
+                    </if>
+                    AND (temperature IS NULL OR temperature BETWEEN 0 AND 80)
+                    AND (humidity IS NULL OR humidity BETWEEN 0 AND 80)
+                    AND (noise IS NULL OR noise BETWEEN 0 AND 80)
+                </where>
+                GROUP BY monitorId, time_slot
+            ) t2 ON t1.monitorId = t2.monitorId AND t1.recodeTime = t2.max_time
+        </foreach>
+        ORDER BY monitorId ASC, recodeTime ASC
+    </select>
+
 </mapper>