diff --git a/nuget-publish.bat b/nuget-publish.bat
index 7bbcd9d2..85d1f74a 100644
--- a/nuget-publish.bat
+++ b/nuget-publish.bat
@@ -1,8 +1,8 @@
 :start
 ::定义版本
-set EFCORE2=2.2.0.20
-set EFCORE3=3.2.0.20
-set EFCORE5=5.2.0.20
+set EFCORE2=2.2.0.21
+set EFCORE3=3.2.0.21
+set EFCORE5=5.2.0.21
 
 ::删除所有bin与obj下的文件
 @echo off
diff --git a/src/ShardingCore/Sharding/Enumerators/StreamMergeAsync/StreamMergeAsyncEnumerator.cs b/src/ShardingCore/Sharding/Enumerators/StreamMergeAsync/StreamMergeAsyncEnumerator.cs
index 163b520d..4b2c71b4 100644
--- a/src/ShardingCore/Sharding/Enumerators/StreamMergeAsync/StreamMergeAsyncEnumerator.cs
+++ b/src/ShardingCore/Sharding/Enumerators/StreamMergeAsync/StreamMergeAsyncEnumerator.cs
@@ -109,10 +109,11 @@ namespace ShardingCore.Sharding.Enumerators
 #if EFCORE2
         public void Dispose()
         {
-             _asyncSource.Dispose();
+            _asyncSource?.Dispose();
+            _syncSource?.Dispose();
         }
 
-        public async Task<bool> MoveNext(CancellationToken cancellationToken=new CancellationToken())
+        public async Task<bool> MoveNext(CancellationToken cancellationToken = new CancellationToken())
         {
             if (skip)
             {
@@ -134,8 +135,13 @@ namespace ShardingCore.Sharding.Enumerators
             {
                 if (tryGetCurrentError)
                     return default;
-                return _asyncSource.Current;
-            }catch(Exception e)
+                if (_asyncSource!= null)
+                    return _asyncSource.Current;
+                if (_syncSource != null)
+                    return _syncSource.Current;
+                return default;
+            }
+            catch (Exception e)
             {
                 tryGetCurrentError = true;
                 return default;