perf(/latestSteamInstantList): 优化查询设备最新记录的性能，避免全表扫描

修改 SQL 查询方式，从设备表驱动并使用 CROSS APPLY 获取每个设备的最新记录
移除 Java 服务层不必要的过滤逻辑，直接使用优化后的查询结果

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

@@ -114,16 +114,9 @@ public class EmsRecordSteamInstantServiceImpl implements IEmsRecordSteamInstantS
         List<EmsRecordSteamInstant> emsRecordSteamInstants = new ArrayList<>();
         //判断监控编码是否为空
         if (monitorCode == null){
-            //没有选择设备，monitorCode为空的时候，分组查询全部设备的最新一条记录
+            //没有选择设备，monitorCode为空的时候，从设备表驱动查询每个设备的最新一条记录
-            List<EmsRecordSteamInstant> allEmsRecordSteamInstants = emsRecordSteamInstantMapper
+            emsRecordSteamInstants = emsRecordSteamInstantMapper
                     .selectEmsRecordLatestSteamInstantList(emsRecordSteamInstant);
-            //遍历查询结果
-            for (EmsRecordSteamInstant recordSteamInstantallEmsRecordSteamInstants : allEmsRecordSteamInstants){
-                //如果有设备名称就添加到返回集合中
-                if (recordSteamInstantallEmsRecordSteamInstants.getMonitorName() != null){
-                    emsRecordSteamInstants.add(recordSteamInstantallEmsRecordSteamInstants);
-                }
-            }
         }else {
             //选择了设备，monitorCode不为空的时候，根据monitorCode查询指定设备的最新一条记录
             emsRecordSteamInstants = emsRecordSteamInstantMapper

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

@@ -213,7 +213,7 @@
     </select>
 -->
 
-    <!-- 查询每个设备的最新一条记录 -->
+    <!-- 查询每个设备的最新一条记录：从设备表驱动，每个设备只取 TOP 1，避免全表扫描 -->
     <select id="selectEmsRecordLatestSteamInstantList" parameterType="EmsRecordSteamInstant" resultMap="EmsRecordSteamInstantResult">
         SELECT
             ersi.obj_id,
@@ -230,15 +230,14 @@
             ersi.difference_press,
             ersi.record_time
         FROM
-            ems_record_steam_instant ersi
+            ems_base_monitor_info ebmi
-                LEFT JOIN ems_base_monitor_info ebmi ON ersi.monitor_code = ebmi.monitor_code
+                CROSS APPLY (
-                INNER JOIN (
+                SELECT TOP 1 *
-                SELECT monitor_code, MAX(obj_id) AS max_obj_id
                 FROM ems_record_steam_instant
-                GROUP BY monitor_code
+                WHERE monitor_code = ebmi.monitor_code
-            ) ersi_max ON ersi.monitor_code = ersi_max.monitor_code AND ersi.obj_id = ersi_max.max_obj_id
+                ORDER BY obj_id DESC
-        ORDER BY ersi.monitor_code ASC;
+            ) ersi
-
+        ORDER BY ersi.monitor_code ASC
     </select>
 
 </mapper>