diff --git a/src/ShardingCore/Core/IShardingQueryable.cs b/src/ShardingCore/Core/IShardingQueryable.cs
index 83df1a2e..649e6800 100644
--- a/src/ShardingCore/Core/IShardingQueryable.cs
+++ b/src/ShardingCore/Core/IShardingQueryable.cs
@@ -55,7 +55,7 @@ namespace ShardingCore.Core
         /// 异步获取列表
         /// </summary>
         /// <returns></returns>
-        Task<List<T>> ToListAsync();
+        Task<List<T>> ToListAsync(int capacity=20);
 
 
         /// <summary>
@@ -111,6 +111,21 @@ namespace ShardingCore.Core
         /// </summary>
         /// <returns></returns>
         Task<float> FloatSumAsync();
+        /// <summary>
+        /// 平均数
+        /// </summary>
+        /// <returns></returns>
+        Task<decimal> DecimalAverageAsync();
+        /// <summary>
+        /// 平均数
+        /// </summary>
+        /// <returns></returns>
+        Task<double> DoubleAverageAsync();
+        /// <summary>
+        /// 平均数
+        /// </summary>
+        /// <returns></returns>
+        Task<float> FloatAverageAsync();
 
     }
 }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/PriorityQueues/PriorityQueue.cs b/src/ShardingCore/Core/Internal/PriorityQueues/PriorityQueue.cs
index 36908f81..88590611 100644
--- a/src/ShardingCore/Core/Internal/PriorityQueues/PriorityQueue.cs
+++ b/src/ShardingCore/Core/Internal/PriorityQueues/PriorityQueue.cs
@@ -13,7 +13,7 @@ namespace ShardingCore.Core.Internal.PriorityQueues {
         public PriorityQueue()
             : this(defaultCapacity) {
         }
-        public PriorityQueue(int initCapacity,bool ascending = false,IComparer<T> comparer=null) {
+        public PriorityQueue(int initCapacity,bool ascending = true,IComparer<T> comparer=null) {
             buffer = new T[initCapacity];
             heapLength = 0;
             descending = ascending;
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/MultiOrderStreamMergeAsyncEnumerator.cs b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/MultiOrderStreamMergeAsyncEnumerator.cs
index 99a4ab6c..06e47ac8 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/MultiOrderStreamMergeAsyncEnumerator.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/MultiOrderStreamMergeAsyncEnumerator.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using ShardingCore.Core.Internal.PriorityQueues;
 using ShardingCore.Core.Internal.StreamMerge.Abstractions;
@@ -16,23 +17,23 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
     internal class MultiOrderStreamMergeAsyncEnumerator<T> : IStreamMergeAsyncEnumerator<T>
     {
         private readonly StreamMergeContext<T> _mergeContext;
-        private readonly IEnumerable<IStreamMergeAsyncEnumerator<T>> _sources;
+        private readonly IEnumerable<IStreamMergeAsyncEnumerator<T>> _enumerators;
         private readonly PriorityQueue<IOrderStreamMergeAsyncEnumerator<T>> _queue;
         private IStreamMergeAsyncEnumerator<T> _currentEnumerator;
         private bool skipFirst;
 
-        public MultiOrderStreamMergeAsyncEnumerator(StreamMergeContext<T> mergeContext, IEnumerable<IStreamMergeAsyncEnumerator<T>> sources)
+        public MultiOrderStreamMergeAsyncEnumerator(StreamMergeContext<T> mergeContext, IEnumerable<IStreamMergeAsyncEnumerator<T>> enumerators)
         {
             _mergeContext = mergeContext;
-            _sources = sources;
-            _queue = new PriorityQueue<IOrderStreamMergeAsyncEnumerator<T>>(sources.Count(),true);
+            _enumerators = enumerators;
+            _queue = new PriorityQueue<IOrderStreamMergeAsyncEnumerator<T>>(enumerators.Count());
             skipFirst = true;
             SetOrderEnumerator();
         }
 
         private void SetOrderEnumerator()
         {
-            foreach (var source in _sources)
+            foreach (var source in _enumerators)
             {
                 var orderStreamEnumerator = new OrderStreamMergeAsyncEnumerator<T>(_mergeContext, source);
                 if (orderStreamEnumerator.HasElement())
@@ -42,10 +43,14 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
                 }
             }
 
-            _currentEnumerator = _queue.IsEmpty() ? _sources.FirstOrDefault() : _queue.Peek();
+            _currentEnumerator = _queue.IsEmpty() ? _enumerators.FirstOrDefault() : _queue.Peek();
         }
-
+#if EFCORE2
+        public async Task<bool> MoveNext(CancellationToken cancellationToken)
+#endif
+#if !EFCORE2
         public async ValueTask<bool> MoveNextAsync()
+#endif
         {
             if (_queue.IsEmpty())
                 return false;
@@ -56,7 +61,12 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
             }
 
             var first = _queue.Poll();
+#if EFCORE2
+            if (await first.MoveNext(cancellationToken))
+#endif
+#if !EFCORE2
             if (await first.MoveNextAsync())
+#endif
             {
                 _queue.Offer(first);
             }
@@ -88,13 +98,26 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
 
         public T ReallyCurrent => _queue.IsEmpty()?default(T):_queue.Peek().ReallyCurrent;
 
+#if !EFCORE2
+
         public async ValueTask DisposeAsync()
         {
-            foreach (var source in _sources)
+            foreach (var enumerator in _enumerators)
             {
-                await source.DisposeAsync();
+                await enumerator.DisposeAsync();
             }
         }
+#endif
+
+#if EFCORE2
+        public  void Dispose()
+        {
+            foreach (var enumerator in _enumerators)
+            {
+                 enumerator.Dispose();
+            }
+        }
+#endif
 
         public T Current => skipFirst ? default : _currentEnumerator.Current;
     }
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEngine.cs
deleted file mode 100644
index ef4bcc30..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEngine.cs
+++ /dev/null
@@ -1,72 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
-using ShardingCore.Core.Internal.StreamMerge.Abstractions;
-
-namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
-{
-/*
-* @Author: xjm
-* @Description:
-* @Date: Friday, 29 January 2021 20:55:42
-* @Email: 326308290@qq.com
-*/
-    internal class NoPaginationStreamMergeEngine<T>:IStreamMergeAsyncEnumerator<T>
-    {
-        private readonly StreamMergeContext<T> _mergeContext;
-        private readonly IStreamMergeAsyncEnumerator<T> _enumerator;
-
-        public NoPaginationStreamMergeEngine(StreamMergeContext<T> mergeContext,IEnumerable<IStreamMergeAsyncEnumerator<T>> sources)
-        {
-            _mergeContext = mergeContext;
-            _enumerator = new MultiOrderStreamMergeAsyncEnumerator<T>(_mergeContext,sources);;
-        }
-
-        public async ValueTask<bool> MoveNextAsync()
-        {
-            //如果合并数据的时候不需要跳过也没有take多少那么就是直接next
-            var skip = _mergeContext.Skip;
-            var take = _mergeContext.Take;
-            var realSkip = 0;
-            var realTake = 0;
-            var has = await _enumerator.MoveNextAsync();
-            if (has)
-            {
-                //获取真实的需要跳过的条数
-                if (skip.HasValue)
-                {
-                    if (realSkip < skip)
-                    {
-                        realSkip++;
-                    }
-                }
-                if (take.HasValue)
-                {
-                    realTake++;
-                    if (realTake <= take.Value)
-                        return false;
-                }
-            }
-
-            return has;
-        }
-
-        public T Current => _enumerator.Current;
-        public bool SkipFirst()
-        {
-            return _enumerator.SkipFirst();
-        }
-
-        public bool HasElement()
-        {
-            return _enumerator.HasElement();
-        }
-
-        public T ReallyCurrent => _enumerator.ReallyCurrent;
-        
-        public async ValueTask DisposeAsync()
-        {
-            await _enumerator.DisposeAsync();
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEnumerator.cs b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEnumerator.cs
new file mode 100644
index 00000000..9616618f
--- /dev/null
+++ b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/NoPaginationStreamMergeEnumerator.cs
@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using ShardingCore.Core.Internal.StreamMerge.Abstractions;
+
+namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
+{
+/*
+* @Author: xjm
+* @Description:
+* @Date: Friday, 29 January 2021 20:55:42
+* @Email: 326308290@qq.com
+*/
+    internal class NoPaginationStreamMergeEnumerator<T>:IStreamMergeAsyncEnumerator<T>
+    {
+        private readonly StreamMergeContext<T> _mergeContext;
+        private readonly IStreamMergeAsyncEnumerator<T> _enumerator;
+        private readonly int? _skip;
+        private readonly int? _take;
+        private int realSkip=0;
+        private int realTake = 0;
+
+        public NoPaginationStreamMergeEnumerator(StreamMergeContext<T> mergeContext,IEnumerable<IStreamMergeAsyncEnumerator<T>> sources)
+        {
+            _mergeContext = mergeContext;
+            _skip = mergeContext.Skip;
+            _take = mergeContext.Take;
+            _enumerator = new MultiOrderStreamMergeAsyncEnumerator<T>(_mergeContext,sources);;
+        }
+#if !EFCORE2
+
+        public async ValueTask<bool> MoveNextAsync()
+#endif
+#if EFCORE2
+
+        public async Task<bool> MoveNext(CancellationToken cancellationToken)
+#endif
+        {
+            //如果合并数据的时候不需要跳过也没有take多少那么就是直接next
+            while (_skip.GetValueOrDefault() > this.realSkip)
+            {
+#if !EFCORE2
+                var has = await _enumerator.MoveNextAsync();
+            
+#endif
+#if EFCORE2
+            var has = await _enumerator.MoveNext(cancellationToken);
+#endif
+                realSkip++;
+                if (!has)
+                    return false;
+            }
+            
+#if !EFCORE2
+            var next = await _enumerator.MoveNextAsync();
+            
+#endif
+#if EFCORE2
+            var next = await _enumerator.MoveNext(cancellationToken);
+#endif
+            if (next)
+            {
+                if (_take.HasValue)
+                {
+                    realTake++;
+                    if (realTake >= _take.Value)
+                        return false;
+                }
+            }
+
+            return next;
+        }
+
+        public T Current => _enumerator.Current;
+        public bool SkipFirst()
+        {
+            return _enumerator.SkipFirst();
+        }
+
+        public bool HasElement()
+        {
+            return _enumerator.HasElement();
+        }
+
+        public T ReallyCurrent => _enumerator.ReallyCurrent;
+        
+#if !EFCORE2
+
+        public async ValueTask DisposeAsync()
+        {
+            await _enumerator.DisposeAsync();
+        }
+#endif
+
+#if EFCORE2
+        public void Dispose()
+        {
+            _enumerator.Dispose();
+        }
+#endif
+    }
+}
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/OrderStreamMergeAsyncEnumerator.cs b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/OrderStreamMergeAsyncEnumerator.cs
index 6a474627..7b9a8b21 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/OrderStreamMergeAsyncEnumerator.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/OrderStreamMergeAsyncEnumerator.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using ShardingCore.Core.Internal.StreamMerge.Abstractions;
 using ShardingCore.Extensions;
@@ -20,13 +21,13 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
         /// </summary>
         private readonly StreamMergeContext<T> _mergeContext;
 
-        private readonly IStreamMergeAsyncEnumerator<T> _source;
+        private readonly IStreamMergeAsyncEnumerator<T> _enumerator;
         private List<IComparable> _orderValues;
 
-        public OrderStreamMergeAsyncEnumerator(StreamMergeContext<T> mergeContext, IStreamMergeAsyncEnumerator<T> source)
+        public OrderStreamMergeAsyncEnumerator(StreamMergeContext<T> mergeContext, IStreamMergeAsyncEnumerator<T> enumerator)
         {
             _mergeContext = mergeContext;
-            _source = source;
+            _enumerator = enumerator;
             SetOrderValues();
         }
 
@@ -34,26 +35,40 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
         {
             _orderValues = HasElement() ? GetCurrentOrderValues() : new List<IComparable>(0);
         }
+        
+#if !EFCORE2
+
         public async ValueTask<bool> MoveNextAsync()
         {
-            var has = await _source.MoveNextAsync();
+            var has = await _enumerator.MoveNextAsync();
             SetOrderValues();
             return has;
         }
+#endif
+        
+#if EFCORE2
 
-        public T Current =>_source.Current;
+        public async Task<bool> MoveNext(CancellationToken cancellationToken)
+        {
+            var has = await _enumerator.MoveNext(cancellationToken);
+            SetOrderValues();
+            return has;
+        }
+#endif
+
+        public T Current =>_enumerator.Current;
 
         public bool SkipFirst()
         {
-            return _source.SkipFirst();
+            return _enumerator.SkipFirst();
         }
 
         public bool HasElement()
         {
-            return _source.HasElement();
+            return _enumerator.HasElement();
         }
 
-        public T ReallyCurrent => _source.ReallyCurrent;
+        public T ReallyCurrent => _enumerator.ReallyCurrent;
 
         private List<IComparable> GetCurrentOrderValues()
         {
@@ -62,7 +77,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
             var list = new List<IComparable>(_mergeContext.Orders.Count());
             foreach (var order in _mergeContext.Orders)
             {
-                var value = _source.ReallyCurrent.GetValueByExpression(order.PropertyExpression);
+                var value = _enumerator.ReallyCurrent.GetValueByExpression(order.PropertyExpression);
                 if (value is IComparable comparable)
                     list.Add(comparable);
                 else
@@ -89,10 +104,19 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
         {
             return _orderValues ?? new List<IComparable>(0);
         }
+#if !EFCORE2
 
-        public ValueTask DisposeAsync()
+        public async ValueTask DisposeAsync()
         {
-            return _source.DisposeAsync();
+            await _enumerator.DisposeAsync();
         }
+#endif
+
+#if EFCORE2
+        public void Dispose()
+        {
+            _enumerator.Dispose();
+        }
+#endif
     }
 }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/StreamMergeAsyncEnumerator.cs b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/StreamMergeAsyncEnumerator.cs
index f926ae13..ea9faa98 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/StreamMergeAsyncEnumerator.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/Enumerators/StreamMergeAsyncEnumerator.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using ShardingCore.Core.Internal.StreamMerge.Abstractions;
 
@@ -24,6 +25,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
         }
 
 
+#if !EFCORE2
         public async ValueTask<bool> MoveNextAsync()
         {
             if (skip)
@@ -34,6 +36,25 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
             return await _source.MoveNextAsync();
         }
 
+#endif
+#if EFCORE2
+        public async Task<bool> MoveNext()
+        {
+            if (skip)
+            {
+                skip = false;
+                return null!=_source.Current;
+            }
+            return await _source.MoveNext();
+        }
+
+#endif
+
+        public Task<bool> MoveNext(CancellationToken cancellationToken)
+        {
+            throw new NotImplementedException();
+        }
+
         public T Current => skip?default:_source.Current;
 
         public bool SkipFirst()
@@ -52,10 +73,19 @@ namespace ShardingCore.Core.Internal.StreamMerge.Enumerators
         }
 
         public T ReallyCurrent => _source.Current;
+#if !EFCORE2
 
         public async ValueTask DisposeAsync()
         {
             await _source.DisposeAsync();
         }
+#endif
+
+#if EFCORE2
+        public void Dispose()
+        {
+            _source.Dispose();
+        }
+#endif
     }
 }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericMergeEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericInMemoryMergeEngine.cs
similarity index 82%
rename from src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericMergeEngine.cs
rename to src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericInMemoryMergeEngine.cs
index 89e1d6b9..01be8e40 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericMergeEngine.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericInMemoryMergeEngine.cs
@@ -4,7 +4,6 @@ using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
 using ShardingCore.Core.Internal.RoutingRuleEngines;
-using ShardingCore.Core.Internal.StreamMerge.ListMerge;
 using ShardingCore.Core.ShardingAccessors;
 using ShardingCore.Extensions;
 
@@ -16,14 +15,18 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
 * @Date: Thursday, 28 January 2021 17:04:29
 * @Email: 326308290@qq.com
 */
-    internal class GenericMergeEngine<T>
+    internal class GenericInMemoryMergeEngine<T>
     {
         private readonly StreamMergeContext<T> _mergeContext;
 
-        public GenericMergeEngine(StreamMergeContext<T> mergeContext)
+        private GenericInMemoryMergeEngine(StreamMergeContext<T> mergeContext)
         {
             _mergeContext = mergeContext;
         }
+        public static GenericInMemoryMergeEngine<T> Create<T>(StreamMergeContext<T> mergeContext)
+        {
+            return new GenericInMemoryMergeEngine<T>(mergeContext);
+        }
         
         private async Task<TResult> EFCoreExecute<TResult>(IQueryable<T> newQueryable,RouteResult routeResult,Func<IQueryable, Task<TResult>> efQuery)
         {
@@ -33,7 +36,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
                 return await efQuery(newQueryable);
             }
         }
-        public async Task<List<TResult>> Execute<TResult>(Func<IQueryable, Task<TResult>> efQuery)
+        public async Task<List<TResult>> ExecuteAsync<TResult>(Func<IQueryable, Task<TResult>> efQuery)
         {
             //从各个分表获取数据
             List<DbContext> parallelDbContexts = new List<DbContext>(_mergeContext.RouteResults.Count());
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeEngine.cs
index 49f51b78..86044726 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeEngine.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeEngine.cs
@@ -6,10 +6,13 @@ using Microsoft.EntityFrameworkCore;
 using ShardingCore.Core.Internal.RoutingRuleEngines;
 using ShardingCore.Core.Internal.StreamMerge.Abstractions;
 using ShardingCore.Core.Internal.StreamMerge.Enumerators;
-using ShardingCore.Core.Internal.StreamMerge.ListMerge;
 using ShardingCore.Core.ShardingAccessors;
 using ShardingCore.Extensions;
 
+#if EFCORE2
+using Microsoft.EntityFrameworkCore.Extensions.Internal;
+#endif
+
 namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
 {
 /*
@@ -18,7 +21,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
 * @Date: Friday, 29 January 2021 15:40:15
 * @Email: 326308290@qq.com
 */
-    internal class GenericStreamMergeEngine<T> :IStreamMergeEngine<T>
+    internal class GenericStreamMergeEngine<T> : IStreamMergeEngine<T>
     {
         private readonly StreamMergeContext<T> _mergeContext;
         private readonly List<DbContext> _parallelDbContexts;
@@ -33,6 +36,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
         {
             return new GenericStreamMergeEngine<T>(mergeContext);
         }
+
         private async Task<IAsyncEnumerator<T>> GetAsyncEnumerator(IQueryable<T> newQueryable, RouteResult routeResult)
         {
             using (var scope = _mergeContext.CreateScope())
@@ -50,7 +54,7 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
             }
         }
 
-        public async Task<IEnumerable<IStreamMergeAsyncEnumerator<T>>> GetStreamEnumerator()
+        public async Task<IStreamMergeAsyncEnumerator<T>> GetStreamEnumerator()
         {
             var enumeratorTasks = _mergeContext.RouteResults.Select(routeResult =>
             {
@@ -61,10 +65,13 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
                     var newQueryable = (IQueryable<T>) _mergeContext.GetReWriteQueryable().ReplaceDbContextQueryable(shardingDbContext);
 
                     var asyncEnumerator = await GetAsyncEnumerator(newQueryable, routeResult);
-                    return new StreamMergeAsyncEnumerator<T>( asyncEnumerator);
+                    return new StreamMergeAsyncEnumerator<T>(asyncEnumerator);
                 });
             }).ToArray();
-            return (await Task.WhenAll(enumeratorTasks)).ToList();
+            var streamEnumerators = await Task.WhenAll(enumeratorTasks);
+            if (_mergeContext.Skip.HasValue || _mergeContext.Take.HasValue)
+                return new NoPaginationStreamMergeEnumerator<T>(_mergeContext,streamEnumerators );
+            return new MultiOrderStreamMergeAsyncEnumerator<T>(_mergeContext, streamEnumerators);
         }
 
 
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeProxyEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeProxyEngine.cs
index a519e3bf..4a744484 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeProxyEngine.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/GenericStreamMergeProxyEngine.cs
@@ -31,13 +31,13 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
 
         public async Task<List<T>> ToListAsync(int capacity=20)
         {
-            var enumerator = new NoPaginationStreamMergeEngine<T>(_mergeContext, await _streamMergeEngine.GetStreamEnumerator());
+            var enumerator = await _streamMergeEngine.GetStreamEnumerator();
             var list = new List<T>(capacity);
 #if !EFCORE2
             while (await enumerator.MoveNextAsync())
 #endif
 #if EFCORE2
-            while (await enumerator.MoveNextAsync())
+            while (await enumerator.MoveNext())
 #endif
             {
                 list.Add(enumerator.Current);
@@ -45,60 +45,6 @@ namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
 
             return list;
         }
-
-        public async Task<T> FirstOrDefaultAsync()
-        {
-            var enumerator = new NoPaginationStreamMergeEngine<T>(_mergeContext, await _streamMergeEngine.GetStreamEnumerator());
-
-#if !EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-#if EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-            {
-                return enumerator.Current;
-            }
-
-            return default;
-        }
-
-        public async Task<bool> AnyAsync()
-        {
-            var enumerator = (IStreamMergeAsyncEnumerator<bool>)new NoPaginationStreamMergeEngine<T>(_mergeContext, await _streamMergeEngine.GetStreamEnumerator());
-
-#if !EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-#if EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-            {
-                if (!enumerator.Current)
-                    return false;
-            }
-
-            return true;
-        }
-        
-
-        public async Task<int> CountAsync()
-        {
-            var enumerator = (IStreamMergeAsyncEnumerator<int>)new NoPaginationStreamMergeEngine<T>(_mergeContext, await _streamMergeEngine.GetStreamEnumerator());
-            var result = 0;
-#if !EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-#if EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-            {
-                result += enumerator.Current;
-            }
-
-            return result;
-        }
-
         public void Dispose()
         {
             _streamMergeEngine.Dispose();
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/ListStreamMergeProxyEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/ListStreamMergeProxyEngine.cs
deleted file mode 100644
index 869ac58c..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/GenericMerges/ListStreamMergeProxyEngine.cs
+++ /dev/null
@@ -1,69 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Threading.Tasks;
-using ShardingCore.Core.Internal.StreamMerge.Enumerators;
-
-namespace ShardingCore.Core.Internal.StreamMerge.GenericMerges
-{
-/*
-* @Author: xjm
-* @Description:
-* @Date: Friday, 29 January 2021 17:55:29
-* @Email: 326308290@qq.com
-*/
-    internal class ListStreamMergeProxyEngine<T>:IDisposable
-    {
-        private readonly StreamMergeContext<T> _mergeContext;
-        private IStreamMergeEngine<T> _streamMergeEngine;
-        private const int defaultCapacity = 0x10;//默认容量为16
-
-
-        public ListStreamMergeProxyEngine(StreamMergeContext<T> mergeContext)
-        {
-            _mergeContext = mergeContext;
-            _streamMergeEngine = GenericStreamMergeEngine<T>.Create(mergeContext);
-        }
-
-        public async Task<List<T>> ToListAsync()
-        {
-            //如果合并数据的时候不需要跳过也没有take多少那么就是直接next
-            var skip = _mergeContext.Skip;
-            var take = _mergeContext.Take;
-            var list = new List<T>(skip.GetValueOrDefault() + take ?? defaultCapacity);
-            var realSkip = 0;
-            var realTake = 0;
-            var enumerator = new MultiOrderStreamMergeAsyncEnumerator<T>(_mergeContext, await _streamMergeEngine.GetStreamEnumerator());
-#if !EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-#if EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-            {
-                //获取真实的需要跳过的条数
-                if (skip.HasValue)
-                {
-                    if (realSkip < skip)
-                    {
-                        realSkip++;
-                        continue;
-                    }
-                }
-                list.Add(enumerator.Current);
-                if (take.HasValue)
-                {
-                    realTake++;
-                    if(realTake<=take.Value)
-                        break;
-                }
-            }
-
-            return list;
-            
-        }
-        public void Dispose()
-        {
-            _streamMergeEngine.Dispose();
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/IStreamMergeEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/IStreamMergeEngine.cs
index 46cfec9a..ac42bdce 100644
--- a/src/ShardingCore/Core/Internal/StreamMerge/IStreamMergeEngine.cs
+++ b/src/ShardingCore/Core/Internal/StreamMerge/IStreamMergeEngine.cs
@@ -13,6 +13,6 @@ namespace ShardingCore.Core.Internal.StreamMerge
 */
     internal interface  IStreamMergeEngine<T>:IDisposable
     {
-        Task<IEnumerable<IStreamMergeAsyncEnumerator<T>>> GetStreamEnumerator();
+        Task<IStreamMergeAsyncEnumerator<T>> GetStreamEnumerator();
     }
 }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderAsyncEnumerator.cs b/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderAsyncEnumerator.cs
deleted file mode 100644
index 33445a26..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderAsyncEnumerator.cs
+++ /dev/null
@@ -1,148 +0,0 @@
-// using System.Collections.Generic;
-// using System.Linq;
-// using System.Threading;
-// using System.Threading.Tasks;
-// using ShardingCore.Core.Internal.PriorityQueues;
-//
-// namespace ShardingCore.Core.Internal.StreamMerge.ListMerge
-// {
-// /*
-// * @Author: xjm
-// * @Description:
-// * @Date: Monday, 25 January 2021 08:06:12
-// * @Email: 326308290@qq.com
-// */
-// #if !EFCORE2
-//     internal class OrderAsyncEnumerator<T> : IAsyncEnumerator<T>
-//     {
-//         private readonly StreamMergeContext<T> _mergeContext;
-//         private readonly List<IAsyncEnumerator<T>> _sources;
-//         private readonly PriorityQueue<OrderMergeItem<T>> _queue;
-//         private bool skipFirst;
-//         private IAsyncEnumerator<T> _currentEnumerator;
-//
-//         public OrderAsyncEnumerator(StreamMergeContext<T> mergeContext,List<IAsyncEnumerator<T>> sources)
-//         {
-//             _mergeContext = mergeContext;
-//             _sources = sources;
-//             _queue = new PriorityQueue<OrderMergeItem<T>>(sources.Count);
-//             skipFirst = true;
-//             SetOrderEnumerator();
-//         }
-//
-//         private void SetOrderEnumerator()
-//         {
-//             foreach (var source in _sources)
-//             {
-//                 var orderMergeItem = new OrderMergeItem<T>(_mergeContext, source);
-//                 if (null!=orderMergeItem.GetCurrentEnumerator().Current)
-//                     _queue.Offer(orderMergeItem);
-//             }
-//             _currentEnumerator = _queue.IsEmpty() ? _sources.FirstOrDefault() : _queue.Peek().GetCurrentEnumerator();
-//         }
-//
-//         public async ValueTask<bool> MoveNextAsync()
-//         {
-//             if (_queue.IsEmpty())
-//                 return false;
-//             if (skipFirst)
-//             {
-//                 skipFirst = false;
-//                 return true;
-//             }
-//
-//             var first = _queue.Poll();
-//             if (await first.MoveNextAsync())
-//             {
-//                 _queue.Offer(first);
-//             }
-//
-//             if (_queue.IsEmpty())
-//             {
-//                 return false;
-//             }
-//
-//             _currentEnumerator = _queue.Peek().GetCurrentEnumerator();
-//             return true;
-//         }
-//
-//         public async ValueTask DisposeAsync()
-//         {
-//             foreach (var source in _sources)
-//             {
-//                 await source.DisposeAsync();
-//             }
-//         }
-//
-//         public T Current => _currentEnumerator.Current;
-//     }
-// #endif
-// #if EFCORE2
-//
-//     internal class OrderAsyncEnumerator<T> : IAsyncEnumerator<T>
-//     {
-//         private readonly StreamMergeContext<T> _mergeContext;
-//         private readonly List<IAsyncEnumerator<T>> _sources;
-//         private readonly PriorityQueue<OrderMergeItem<T>> _queue;
-//         private bool skipFirst;
-//         private IAsyncEnumerator<T> _currentEnumerator;
-//
-//         public OrderAsyncEnumerator(StreamMergeContext<T> mergeContext, List<IAsyncEnumerator<T>> sources)
-//         {
-//             _mergeContext = mergeContext;
-//             _sources = sources;
-//             _queue = new PriorityQueue<OrderMergeItem<T>>(sources.Count);
-//             skipFirst = true;
-//             SetOrderEnumerator();
-//         }
-//
-//         private void SetOrderEnumerator()
-//         {
-//             foreach (var source in _sources)
-//             {
-//                 var orderMergeItem = new OrderMergeItem<T>(_mergeContext, source);
-//                 if (null!=orderMergeItem.GetCurrentEnumerator().Current)
-//                     _queue.Offer(orderMergeItem);
-//             }
-//
-//             _currentEnumerator = _queue.IsEmpty() ? _sources.FirstOrDefault() : _queue.Peek().GetCurrentEnumerator();
-//         }
-//
-//         public async Task<bool> MoveNext(CancellationToken cancellationToken)
-//         {
-//             if (_queue.IsEmpty())
-//                 return false;
-//             if (skipFirst)
-//             {
-//                 skipFirst = false;
-//                 return true;
-//             }
-//
-//             var first = _queue.Poll();
-//             if (await first.MoveNextAsync())
-//             {
-//                 _queue.Offer(first);
-//             }
-//
-//             if (_queue.IsEmpty())
-//             {
-//                 return false;
-//             }
-//
-//             _currentEnumerator = _queue.Peek().GetCurrentEnumerator();
-//             return true;
-//         }
-//
-//         public void Dispose()
-//         {
-//             foreach (var source in _sources)
-//             {
-//                 source.Dispose();
-//             }
-//         }
-//
-//
-//         public T Current => _currentEnumerator.Current;
-//     }
-// #endif
-// }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderMergeItem.cs b/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderMergeItem.cs
deleted file mode 100644
index 5ee0dca1..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/OrderMergeItem.cs
+++ /dev/null
@@ -1,158 +0,0 @@
-// using System;
-// using System.Collections.Generic;
-// using System.Linq;
-// using System.Threading.Tasks;
-// using ShardingCore.Extensions;
-//
-// namespace ShardingCore.Core.Internal.StreamMerge.ListMerge
-// {
-// /*
-// * @Author: xjm
-// * @Description:
-// * @Date: Monday, 25 January 2021 11:33:57
-// * @Email: 326308290@qq.com
-// */
-// #if !EFCORE2
-//     
-//     internal class OrderMergeItem<T> : IComparable<OrderMergeItem<T>>, IAsyncDisposable
-//     {
-//         /// <summary>
-//         /// 合并数据上下文
-//         /// </summary>
-//         private readonly StreamMergeContext<T> _mergeContext;
-//
-//         private readonly IAsyncEnumerator<T> _source;
-//         private List<IComparable> _orderValues;
-//
-//         public OrderMergeItem(StreamMergeContext<T> mergeContext, IAsyncEnumerator<T> source)
-//         {
-//             _mergeContext = mergeContext;
-//             _source = source;
-//             SetOrderValues(null!=GetCurrentEnumerator().Current);
-//         }
-//
-//         public IAsyncEnumerator<T> GetCurrentEnumerator() => _source;
-//
-//         private void SetOrderValues(bool hasElement)
-//         {
-//             _orderValues = hasElement ? GetCurrentOrderValues() : new List<IComparable>(0);
-//         }
-//         public async Task<bool> MoveNextAsync()
-//         {
-//             var has = await _source.MoveNextAsync();
-//             SetOrderValues(has);
-//             return has;
-//         }
-//
-//         public bool HasElement()
-//         {
-//             
-//         }
-//
-//         private List<IComparable> GetCurrentOrderValues()
-//         {
-//             if (!_mergeContext.Orders.Any())
-//                 return new List<IComparable>(0);
-//             var list = new List<IComparable>(_mergeContext.Orders.Count());
-//             foreach (var order in _mergeContext.Orders)
-//             {
-//                 var value = GetCurrentEnumerator().Current.GetValueByExpression(order.PropertyExpression);
-//                 if (value is IComparable comparable)
-//                     list.Add(comparable);
-//                 else
-//                     throw new NotSupportedException($"order by value [{order}] must  implements IComparable");
-//             }
-//
-//             return list;
-//         }
-//
-//         public int CompareTo(OrderMergeItem<T> other)
-//         {
-//             int i = 0;
-//             foreach (var order in _mergeContext.Orders) {
-//                 int result = CompareHelper.CompareToWith(_orderValues[i], other._orderValues[i], order.IsAsc);
-//                 if (0 != result) {
-//                     return result;
-//                 }
-//                 i++;
-//             }
-//             return 0;
-//         }
-//
-//         public ValueTask DisposeAsync()
-//         {
-//             return _source.DisposeAsync();
-//         }
-//     }
-// #endif
-// #if EFCORE2
-//     
-//     internal class OrderMergeItem<T> : IComparable<OrderMergeItem<T>>, IDisposable
-//     {
-//         /// <summary>
-//         /// 合并数据上下文
-//         /// </summary>
-//         private readonly StreamMergeContext<T> _mergeContext;
-//
-//         private readonly IAsyncEnumerator<T> _source;
-//         private List<IComparable> _orderValues;
-//
-//         public OrderMergeItem(StreamMergeContext<T> mergeContext, IAsyncEnumerator<T> source)
-//         {
-//             _mergeContext = mergeContext;
-//             _source = source;
-//             SetOrderValues(null!=GetCurrentEnumerator().Current);
-//         }
-//
-//         public IAsyncEnumerator<T> GetCurrentEnumerator() => _source;
-//
-//         private void SetOrderValues(bool hasElement)
-//         {
-//             _orderValues = hasElement ? GetCurrentOrderValues() : new List<IComparable>(0);
-//         }
-//
-//         public async Task<bool> MoveNextAsync()
-//         {
-//             var has = await _source.MoveNext();
-//             SetOrderValues(has);
-//             return has;
-//         }
-//
-//         private List<IComparable> GetCurrentOrderValues()
-//         {
-//             if (!_mergeContext.Orders.Any())
-//                 return new List<IComparable>(0);
-//             var list = new List<IComparable>(_mergeContext.Orders.Count());
-//             foreach (var order in _mergeContext.Orders)
-//             {
-//                 var value = GetCurrentEnumerator().Current.GetValueByExpression(order.PropertyExpression);
-//                 if (value is IComparable comparable)
-//                     list.Add(comparable);
-//                 else
-//                     throw new NotSupportedException($"order by value [{order}] must  implements IComparable");
-//             }
-//
-//             return list;
-//         }
-//
-//         public int CompareTo(OrderMergeItem<T> other)
-//         {
-//             int i = 0;
-//             foreach (var order in _mergeContext.Orders) {
-//                 int result = CompareHelper.CompareToWith(_orderValues[i], other._orderValues[i], order.IsAsc);
-//                 if (0 != result) {
-//                     return result;
-//                 }
-//                 i++;
-//             }
-//             return 0;
-//         }
-//
-//
-//         public void Dispose()
-//         {
-//              _source.Dispose();
-//         }
-//     }
-// #endif
-// }
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/StreamMergeListEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/StreamMergeListEngine.cs
deleted file mode 100644
index eff8d877..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/ListMerge/StreamMergeListEngine.cs
+++ /dev/null
@@ -1,66 +0,0 @@
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-using Microsoft.EntityFrameworkCore;
-using ShardingCore.Core.Internal.StreamMerge.Abstractions;
-using ShardingCore.Core.Internal.StreamMerge.Enumerators;
-using ShardingCore.Extensions;
-
-namespace ShardingCore.Core.Internal.StreamMerge.ListMerge
-{
-/*
-* @Author: xjm
-* @Description:
-* @Date: Monday, 25 January 2021 07:57:59
-* @Email: 326308290@qq.com
-*/
-    internal class StreamMergeListEngine<T>
-    {
-        private const int defaultCapacity = 0x10;//默认容量为16
-        private readonly StreamMergeContext<T> _mergeContext;
-        private readonly IStreamMergeAsyncEnumerator<T> _streamMergeAsyncEnumerator;
-
-        public StreamMergeListEngine(StreamMergeContext<T> mergeContext,IEnumerable<IStreamMergeAsyncEnumerator<T>> sources)
-        {
-            _mergeContext = mergeContext;
-            _streamMergeAsyncEnumerator = new MultiOrderStreamMergeAsyncEnumerator<T>(_mergeContext,sources);
-        }
-
-        public async Task<List<T>> Execute()
-        {
-            //如果合并数据的时候不需要跳过也没有take多少那么就是直接next
-            var skip = _mergeContext.Skip;
-            var take = _mergeContext.Take;
-            var list = new List<T>(skip.GetValueOrDefault() + take ?? defaultCapacity);
-            var realSkip = 0;
-            var realTake = 0;
-#if !EFCORE2
-            while (await _streamMergeAsyncEnumerator.MoveNextAsync())
-#endif
-#if EFCORE2
-            while (await enumerator.MoveNextAsync())
-#endif
-            {
-                //获取真实的需要跳过的条数
-                if (skip.HasValue)
-                {
-                    if (realSkip < skip)
-                    {
-                        realSkip++;
-                        continue;
-                    }
-                }
-                list.Add(_streamMergeAsyncEnumerator.Current);
-                if (take.HasValue)
-                {
-                    realTake++;
-                    if(realTake<=take.Value)
-                        break;
-                }
-            }
-
-            return list;
-        }
-        
-    }
-}
\ No newline at end of file
diff --git a/src/ShardingCore/Core/Internal/StreamMerge/ListSourceMerges/StreamMergeListSourceEngine.cs b/src/ShardingCore/Core/Internal/StreamMerge/ListSourceMerges/StreamMergeListSourceEngine.cs
deleted file mode 100644
index 566e8457..00000000
--- a/src/ShardingCore/Core/Internal/StreamMerge/ListSourceMerges/StreamMergeListSourceEngine.cs
+++ /dev/null
@@ -1,42 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-using Microsoft.EntityFrameworkCore;
-using ShardingCore.Core.Internal.RoutingRuleEngines;
-using ShardingCore.Core.Internal.StreamMerge.GenericMerges;
-using ShardingCore.Core.Internal.StreamMerge.ListMerge;
-using ShardingCore.Core.ShardingAccessors;
-using ShardingCore.Extensions;
-#if EFCORE2
-using Microsoft.EntityFrameworkCore.Extensions.Internal;
-#endif
-
-namespace ShardingCore.Core.Internal.StreamMerge.ListSourceMerges
-{
-/*
-* @Author: xjm
-* @Description:
-* @Date: Thursday, 28 January 2021 14:45:19
-* @Email: 326308290@qq.com
-*/
-    internal class StreamMergeListSourceEngine<T>
-    {
-        private readonly StreamMergeContext<T> _mergeContext;
-
-        public StreamMergeListSourceEngine(StreamMergeContext<T> mergeContext)
-        {
-            _mergeContext = mergeContext;
-        }
-        
-        public async Task<List<T>> Execute()
-        {
-             using (var engine =new GenericStreamMergeEngine<T>(_mergeContext))
-             {
-                 var enumerators = await engine.GetStreamEnumerator();
-                 
-                 return await new StreamMergeListEngine<T>(_mergeContext, enumerators).Execute();
-             }
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/ShardingCore/Core/ShardingQueryable.cs b/src/ShardingCore/Core/ShardingQueryable.cs
index 0f6c96e4..6d6d6097 100644
--- a/src/ShardingCore/Core/ShardingQueryable.cs
+++ b/src/ShardingCore/Core/ShardingQueryable.cs
@@ -8,12 +8,7 @@ using Microsoft.Extensions.DependencyInjection;
 using ShardingCore.Core.Internal.RoutingRuleEngines;
 using ShardingCore.Core.Internal.StreamMerge;
 using ShardingCore.Core.Internal.StreamMerge.GenericMerges;
-using ShardingCore.Core.Internal.StreamMerge.ListMerge;
-using ShardingCore.Core.Internal.StreamMerge.ListSourceMerges;
-using ShardingCore.Core.ShardingAccessors;
-using ShardingCore.Core.VirtualRoutes;
 using ShardingCore.Core.VirtualTables;
-using ShardingCore.DbContexts;
 using ShardingCore.Extensions;
 #if EFCORE2
 using Microsoft.EntityFrameworkCore.Extensions.Internal;
@@ -31,6 +26,7 @@ namespace ShardingCore.Core
     /// 分表查询构造器
     /// </summary>
     /// <typeparam name="T"></typeparam>
+    
     public class ShardingQueryable<T> : IShardingQueryable<T>
     {
         private IQueryable<T> _source;
@@ -41,13 +37,18 @@ namespace ShardingCore.Core
         private readonly IRoutingRuleEngineFactory _routingRuleEngineFactory;
 
 
-        public ShardingQueryable(IQueryable<T> source)
+        private ShardingQueryable(IQueryable<T> source)
         {
             _source = source;
             _streamMergeContextFactory = ShardingContainer.Services.GetService<IStreamMergeContextFactory>();
             _routingRuleEngineFactory=ShardingContainer.Services.GetService<IRoutingRuleEngineFactory>();
         }
 
+        public static ShardingQueryable<TSource> Create<TSource>(IQueryable<TSource> source)
+        {
+            return new ShardingQueryable<TSource>(source);
+        }
+
 
         public IShardingQueryable<T> EnableAutoRouteParse()
         {
@@ -104,7 +105,7 @@ namespace ShardingCore.Core
         }
         private async Task<List<TResult>> GetGenericMergeEngine<TResult>(Func<IQueryable, Task<TResult>> efQuery)
         {
-            return await new GenericMergeEngine<T>(GetContext()).Execute(efQuery);
+            return await GenericInMemoryMergeEngine<T>.Create(GetContext()).ExecuteAsync(efQuery);
         }
 
         public async Task<int> CountAsync()
@@ -120,12 +121,12 @@ namespace ShardingCore.Core
         }
 
 
-        public async Task<List<T>> ToListAsync()
+        public async Task<List<T>> ToListAsync(int capacity=20)
         {
             var context = GetContext();
             using (var engine =  GenericStreamMergeProxyEngine<T>.Create(context))
             {
-                return await engine.ToListAsync();
+                return await engine.ToListAsync(capacity);
             }
         }
 
@@ -133,10 +134,13 @@ namespace ShardingCore.Core
         public async Task<T> FirstOrDefaultAsync()
         {
             var context = GetContext();
-            using (var engine =  GenericStreamMergeProxyEngine<T>.Create(context))
-            {
-                return await engine.FirstOrDefaultAsync();
-            }
+            var result= await GenericInMemoryMergeEngine<T>.Create(context).ExecuteAsync(async queryable => await EntityFrameworkQueryableExtensions.FirstOrDefaultAsync((IQueryable<T>) queryable));
+            var q = result.Where(o => o != null).AsQueryable();
+            if (context.Orders.Any())
+                return  q.OrderWithExpression(context.Orders).FirstOrDefault();
+
+            return q.FirstOrDefault();
+            
         }
 
         public async Task<bool> AnyAsync()
@@ -145,6 +149,7 @@ namespace ShardingCore.Core
                 .Any(o => o);
         }
 
+
         public async Task<T> MaxAsync()
         {
             var results = await GetGenericMergeEngine(async queryable => await EntityFrameworkQueryableExtensions.MaxAsync((IQueryable<T>) queryable));
@@ -197,6 +202,28 @@ namespace ShardingCore.Core
             return results.Sum();
         }
 
+        public async Task<decimal> DecimalAverageAsync()
+        {
+            if (typeof(T) != typeof(decimal))
+                throw new InvalidOperationException($"{typeof(T)} cast to decimal failed");
+            var results = await GetGenericMergeEngine(async queryable => await EntityFrameworkQueryableExtensions.AverageAsync((IQueryable<decimal>) queryable));
+            return results.Sum()/results.Count();
+        }
 
+        public async Task<double> DoubleAverageAsync()
+        {
+            if (typeof(T) != typeof(double))
+                throw new InvalidOperationException($"{typeof(T)} cast to double failed");
+            var results = await GetGenericMergeEngine(async queryable => await EntityFrameworkQueryableExtensions.AverageAsync((IQueryable<double>) queryable));
+            return results.Sum()/results.Count();
+        }
+
+        public async  Task<float> FloatAverageAsync()
+        {
+            if (typeof(T) != typeof(float))
+                throw new InvalidOperationException($"{typeof(T)} cast to float failed");
+            var results = await GetGenericMergeEngine(async queryable => await EntityFrameworkQueryableExtensions.AverageAsync((IQueryable<float>) queryable));
+            return results.Sum()/results.Count();
+        }
     }
 }
\ No newline at end of file
diff --git a/src/ShardingCore/Extensions/ShardingExtension.cs b/src/ShardingCore/Extensions/ShardingExtension.cs
index 2416e597..70db92ad 100644
--- a/src/ShardingCore/Extensions/ShardingExtension.cs
+++ b/src/ShardingCore/Extensions/ShardingExtension.cs
@@ -23,11 +23,11 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static IShardingQueryable<T> AsSharding<T>(this IQueryable<T> source)
         {
-            return new ShardingQueryable<T>(source);
+            return ShardingQueryable<T>.Create(source);
         }
         public static async Task<bool> ShardingAnyAsync<T>(this IQueryable<T> source, Expression<Func<T, bool>> predicate)
         {
-            return await new ShardingQueryable<T>(source.Where(predicate)).AnyAsync();
+            return await ShardingQueryable<T>.Create(source.Where(predicate)).AnyAsync();
         }
         /// <summary>
         /// 分页
@@ -37,7 +37,7 @@ namespace ShardingCore.Extensions
         /// <param name="pageSize"></param>
         /// <typeparam name="T"></typeparam>
         /// <returns></returns>
-        public static async Task<ShardingPagedResult<T>> ToShardingPageResultAsync<T>(this IQueryable<T> source, int pageIndex, int pageSize)
+        public static async Task<ShardingPagedResult<T>> ShardingPageResultAsync<T>(this IQueryable<T> source, int pageIndex, int pageSize)
         {
             //设置每次获取多少页
             var take = pageSize <= 0 ? 1 : pageSize;
@@ -46,7 +46,7 @@ namespace ShardingCore.Extensions
             //需要跳过多少页
             var skip = (index - 1) * take;
             //获取每次总记录数
-            var count = await new ShardingQueryable<T>(source).CountAsync();
+            var count = await ShardingQueryable<T>.Create(source).CountAsync();
             
             //当数据库数量小于要跳过的条数就说明没数据直接返回不在查询list
             if (count <= skip)
@@ -55,7 +55,7 @@ namespace ShardingCore.Extensions
             int remainingCount = count - skip;
             //当剩余条数小于take数就取remainingCount
             var realTake = remainingCount < take ? remainingCount : take;
-            var data = await new ShardingQueryable<T>(source.Skip(skip).Take(realTake)).ToListAsync();
+            var data = await ShardingQueryable<T>.Create(source.Skip(skip).Take(realTake)).ToListAsync(realTake);
             return new ShardingPagedResult<T>(data, count);
         }
         /// <summary>
@@ -66,7 +66,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static List<T> ToShardingList<T>(this IQueryable<T> source)
         {
-            return  new ShardingQueryable<T>(source).ToList();
+            return  ShardingQueryable<T>.Create(source).ToList();
         }
         /// <summary>
         /// 分页
@@ -76,7 +76,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static async Task<List<T>> ToShardingListAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).ToListAsync();
+            return await ShardingQueryable<T>.Create(source).ToListAsync();
         }
         /// <summary>
         /// 第一条
@@ -86,7 +86,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static T ShardingFirstOrDefault<T>(this IQueryable<T> source)
         {
-            return  new ShardingQueryable<T>(source).FirstOrDefault();
+            return  ShardingQueryable<T>.Create(source).FirstOrDefault();
         }
         /// <summary>
         /// 第一条
@@ -96,7 +96,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static async Task<T> ShardingFirstOrDefaultAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).FirstOrDefaultAsync();
+            return await ShardingQueryable<T>.Create(source).FirstOrDefaultAsync();
         }
         /// <summary>
         /// 最大
@@ -106,7 +106,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static T ShardingMax<T>(this IQueryable<T> source)
         {
-            return  new ShardingQueryable<T>(source).Max();
+            return  ShardingQueryable<T>.Create(source).Max();
         }
         /// <summary>
         /// 最大
@@ -116,7 +116,7 @@ namespace ShardingCore.Extensions
         /// <returns></returns>
         public static async Task<T> ShardingMaxAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).MaxAsync();
+            return await ShardingQueryable<T>.Create(source).MaxAsync();
         }
         /// <summary>
         /// 最大
@@ -144,11 +144,11 @@ namespace ShardingCore.Extensions
         }
         public static T ShardingMin<T>(this IQueryable<T> source)
         {
-            return  new ShardingQueryable<T>(source).Min();
+            return  ShardingQueryable<T>.Create(source).Min();
         }
         public static async Task<T> ShardingMinAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).MinAsync();
+            return await ShardingQueryable<T>.Create(source).MinAsync();
         }
         /// <summary>
         /// 最小
@@ -176,27 +176,27 @@ namespace ShardingCore.Extensions
         }
         public static int ShardingCount<T>(this IQueryable<T> source)
         {
-            return new ShardingQueryable<T>(source).Count();
+            return ShardingQueryable<T>.Create(source).Count();
         }
         public static async Task<int> ShardingCountAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).CountAsync();
+            return await ShardingQueryable<T>.Create(source).CountAsync();
         }
         public static long ShardingLongCount<T>(this IQueryable<T> source)
         {
-            return  new ShardingQueryable<T>(source).LongCount();
+            return  ShardingQueryable<T>.Create(source).LongCount();
         }
         public static async Task<long> ShardingLongCountAsync<T>(this IQueryable<T> source)
         {
-            return await new ShardingQueryable<T>(source).LongCountAsync();
+            return await ShardingQueryable<T>.Create(source).LongCountAsync();
         }
         public static int ShardingSum(this IQueryable<int> source)
         {
-            return  new ShardingQueryable<int>(source).Sum();
+            return  ShardingQueryable<int>.Create(source).Sum();
         }
         public static async Task<int> ShardingSumAsync(this IQueryable<int> source)
         {
-            return await new ShardingQueryable<int>(source).SumAsync();
+            return await ShardingQueryable<int>.Create(source).SumAsync();
         }
         public static int ShardingSum<T>(this IQueryable<T> source,Expression<Func<T,int>> keySelector)
         {
@@ -208,11 +208,11 @@ namespace ShardingCore.Extensions
         }
         public static long ShardingSum(this IQueryable<long> source)
         {
-            return  new ShardingQueryable<long>(source).LongSum();
+            return  ShardingQueryable<long>.Create(source).LongSum();
         }
         public static async Task<long> ShardingSumAsync(this IQueryable<long> source)
         {
-            return await new ShardingQueryable<long>(source).LongSumAsync();
+            return await ShardingQueryable<long>.Create(source).LongSumAsync();
         }
         public static long ShardingSum<T>(this IQueryable<T> source,Expression<Func<T,long>> keySelector)
         {
@@ -224,11 +224,11 @@ namespace ShardingCore.Extensions
         }
         public static double ShardingSum(this IQueryable<double> source)
         {
-            return  new ShardingQueryable<double>(source).DoubleSum();
+            return ShardingQueryable<double>.Create(source).DoubleSum();
         }
         public static async Task<double> ShardingSumAsync(this IQueryable<double> source)
         {
-            return await new ShardingQueryable<double>(source).DoubleSumAsync();
+            return await ShardingQueryable<double>.Create(source).DoubleSumAsync();
         }
         public static double ShardingSum<T>(this IQueryable<T> source,Expression<Func<T,double>> keySelector)
         {
@@ -240,11 +240,11 @@ namespace ShardingCore.Extensions
         }
         public static decimal ShardingSum(this IQueryable<decimal> source)
         {
-            return  new ShardingQueryable<decimal>(source).DecimalSum();
+            return  ShardingQueryable<decimal>.Create(source).DecimalSum();
         }
         public static async Task<decimal> ShardingSumAsync(this IQueryable<decimal> source)
         {
-            return await new ShardingQueryable<decimal>(source).DecimalSumAsync();
+            return await ShardingQueryable<decimal>.Create(source).DecimalSumAsync();
         }
         public static decimal ShardingSum<T>(this IQueryable<T> source,Expression<Func<T,decimal>> keySelector)
         {
@@ -256,11 +256,11 @@ namespace ShardingCore.Extensions
         }
         public static float ShardingSum(this IQueryable<float> source)
         {
-            return  new ShardingQueryable<float>(source).FloatSum();
+            return  ShardingQueryable<float>.Create(source).FloatSum();
         }
         public static async Task<float> ShardingSumAsync(this IQueryable<float> source)
         {
-            return await new ShardingQueryable<float>(source).FloatSumAsync();
+            return await ShardingQueryable<float>.Create(source).FloatSumAsync();
         }
         public static float ShardingSum<T>(this IQueryable<T> source,Expression<Func<T,float>> keySelector)
         {
diff --git a/test/ShardingCore.Test50.MySql/ShardingTest.cs b/test/ShardingCore.Test50.MySql/ShardingTest.cs
index 01217633..6e49bc13 100644
--- a/test/ShardingCore.Test50.MySql/ShardingTest.cs
+++ b/test/ShardingCore.Test50.MySql/ShardingTest.cs
@@ -63,6 +63,8 @@ namespace ShardingCore.Test50.MySql
                 Assert.Contains(sysUserMods, o =>o.Id==id);
                 Assert.Contains(sysUserRanges, o =>o.Id==id);
             }
+            Assert.DoesNotContain(sysUserMods,o=>o.Age>4);
+            Assert.DoesNotContain(sysUserRanges,o=>o.Age>4);
         }
         [Fact]
         public async Task ToList_Id_Eq_Test()
@@ -85,6 +87,21 @@ namespace ShardingCore.Test50.MySql
             Assert.DoesNotContain(ranges,o=>o.Id=="3");
         }
         [Fact]
+        public async Task ToList_Id_Not_Eq_Skip_Test()
+        {
+            var mods=await _virtualDbContext.Set<SysUserMod>().Where(o=>o.Id!="3").OrderBy(o=>o.Age).Skip(2).ToShardingListAsync();
+            Assert.Equal(97,mods.Count);
+            Assert.DoesNotContain(mods,o=>o.Id=="3");
+            Assert.Equal(4,mods[0].Age);
+            Assert.Equal(5,mods[1].Age);
+            
+            var modsDesc=await _virtualDbContext.Set<SysUserMod>().Where(o=>o.Id!="3").OrderByDescending(o=>o.Age).Skip(13).ToShardingListAsync();
+            Assert.Equal(86,modsDesc.Count);
+            Assert.DoesNotContain(mods,o=>o.Id=="3");
+            Assert.Equal(87,modsDesc[0].Age);
+            Assert.Equal(86,modsDesc[1].Age);
+        }
+        [Fact]
         public async Task ToList_Name_Eq_Test()
         {
             var mods=await _virtualDbContext.Set<SysUserMod>().Where(o=>o.Name=="name_3").ToShardingListAsync();