diff --git a/sql/migrate_kpi_area_info_area_id_index.sql b/sql/migrate_kpi_area_info_area_id_index.sql
new file mode 100644
index 0000000..da86588
--- /dev/null
+++ b/sql/migrate_kpi_area_info_area_id_index.sql
@@ -0,0 +1,18 @@
+-- 分区明细按 AreaId 全量/分页查询时避免 filesort 打满 sort_buffer（查价 LIVE 路径易踩）
+SET @db := DATABASE();
+
+SET @idx := (
+  SELECT COUNT(1)
+  FROM information_schema.STATISTICS
+  WHERE TABLE_SCHEMA = @db
+    AND TABLE_NAME = 't_kpi_area_info'
+    AND INDEX_NAME = 'idx_kpi_info_area_id'
+);
+SET @sql := IF(
+  @idx = 0,
+  'ALTER TABLE `t_kpi_area_info` ADD KEY `idx_kpi_info_area_id` (`AreaId`, `Id`)',
+  'SELECT ''idx_kpi_info_area_id already exists'' AS info'
+);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
diff --git a/src/Oms.SqlSugarCore/Channels/KpiAreaRepository.cs b/src/Oms.SqlSugarCore/Channels/KpiAreaRepository.cs
index b06e0e4..c887260 100644
--- a/src/Oms.SqlSugarCore/Channels/KpiAreaRepository.cs
+++ b/src/Oms.SqlSugarCore/Channels/KpiAreaRepository.cs
@@ -21,9 +21,10 @@ public class KpiAreaRepository : OmsSqlSugarRepository<KpiArea>, IKpiAreaReposit
     public async Task<List<KpiAreaInfo>> GetInfosAsync(int areaId, int pageIndex, int pageSize, CancellationToken cancellationToken = default)
     {
         var db = await GetDbContextAsync(cancellationToken);
+        // 依赖 idx_kpi_info_area_id (AreaId, Id)，避免大分区 filesort
         return await db.Queryable<KpiAreaInfo>()
             .Where(x => x.AreaId == areaId)
-            .OrderBy(x => x.Id, SqlSugar.OrderByType.Desc)
+            .OrderBy(x => x.Id, OrderByType.Desc)
             .ToPageListAsync(pageIndex, pageSize, cancellationToken);
     }
 
@@ -66,9 +67,10 @@ public class KpiAreaRepository : OmsSqlSugarRepository<KpiArea>, IKpiAreaReposit
     public async Task<List<KpiAreaInfo>> GetAllInfosByAreaIdAsync(int areaId, CancellationToken cancellationToken = default)
     {
         var db = await GetDbContextAsync(cancellationToken);
+        // 大分区表（如美区邮编）全量 ORDER BY 会打满 MySQL sort_buffer 导致 500；
+        // 需要稳定顺序的调用方在内存中排序（如 EnsurePackAsync）。
         return await db.Queryable<KpiAreaInfo>()
             .Where(x => x.AreaId == areaId)
-            .OrderBy(x => x.Id)
             .ToListAsync(cancellationToken);
     }