From 197cb36b96d4c844de7f00239210565ece2a7204 Mon Sep 17 00:00:00 2001
From: Christoph Fink <fink.christoph@gmail.com>
Date: Sat, 7 Sep 2019 11:17:48 +0200
Subject: [PATCH] Fix for #1217

---
 .../Core/Query/InternalTrees/VarVec.cs           | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/src/EntityFramework/Core/Query/InternalTrees/VarVec.cs b/src/EntityFramework/Core/Query/InternalTrees/VarVec.cs
index 07a9d2c97a..ef7fb96fab 100644
--- a/src/EntityFramework/Core/Query/InternalTrees/VarVec.cs
+++ b/src/EntityFramework/Core/Query/InternalTrees/VarVec.cs
@@ -843,11 +843,11 @@ private static int GetArraySize(int n, int div)
 
         private class ArrayPool
         {
-            private Dictionary<int, ConcurrentBag<int[]>> dictionary;
+            private ConcurrentDictionary<int, ConcurrentBag<int[]>> dictionary;
 
             private ArrayPool()
             {
-                dictionary = new Dictionary<int, ConcurrentBag<int[]>>();
+                dictionary = new ConcurrentDictionary<int, ConcurrentBag<int[]>>();
             }
 
             private static readonly ArrayPool instance = new ArrayPool();
@@ -872,17 +872,7 @@ public int[] GetArray(int length)
 
             private ConcurrentBag<int[]> GetBag(int length)
             {
-                ConcurrentBag<int[]> arrays;
-                if (!dictionary.ContainsKey(length))
-                {
-                    arrays = new ConcurrentBag<int[]>();
-                    dictionary[length] = arrays;
-                }
-                else
-                {
-                    arrays = dictionary[length];
-                }
-                return arrays;
+				return dictionary.GetOrAdd(length, l => new ConcurrentBag<int[]>());
             }
 
             public void PutArray(int[] arr)