handle warm

Author: Alex Peck

BitFaster.Caching.UnitTests/Lru/ConcurrentLruTests.cs

@@ -684,10 +684,12 @@ public void WhenItemRemovedFromHotDuringWarmupItIsEagerlyCycledOut()
             lru.GetOrAdd(1, valueFactory.Create);
 
             lru.TryRemove(1);
+            Print();                                    // Hot [1] Warm [] Cold []
 
             lru.GetOrAdd(1, valueFactory.Create);
             lru.GetOrAdd(2, valueFactory.Create);
             lru.GetOrAdd(3, valueFactory.Create);
+            Print();                                    // Hot [1,2,3] Warm [] Cold []
 
             lru.WarmCount.Should().Be(0);
             lru.ColdCount.Should().Be(0);
@@ -701,21 +703,67 @@ public void WhenItemRemovedFromHotAfterWarmupItIsEagerlyCycledOut()
                 lru.GetOrAdd(i, valueFactory.Create);
             }
 
+            Print();                                    // Hot [6,7,8] Warm [1,2,3] Cold [0,4,5]
             lru.Metrics.Value.Evicted.Should().Be(0);
-
+ 
             lru.GetOrAdd(-1, valueFactory.Create);
 
             lru.TryRemove(-1);
+            Print();                                   // Hot[7, 8, -1] Warm[1, 2, 3] Cold[4, 5, 6]
 
             // fully cycle hot, which is 3 items
             lru.GetOrAdd(-2, valueFactory.Create);
             lru.GetOrAdd(-3, valueFactory.Create);
             lru.GetOrAdd(-4, valueFactory.Create);
 
+            Print();                                    // Hot [-2,-3,-4] Warm [1,2,3] Cold [6,7,8]
+
             // without eager eviction as -1 is purged from hot, a 4th item will pushed out since hot queue is full
             lru.Metrics.Value.Evicted.Should().Be(3);
         }
 
+        [Fact]
+        public void WhenItemRemovedFromWarmDuringWarmupItIsEagerlyCycledOut()
+        {
+            lru.GetOrAdd(1, valueFactory.Create);
+            lru.GetOrAdd(2, valueFactory.Create);
+            lru.GetOrAdd(3, valueFactory.Create);
+            lru.GetOrAdd(4, valueFactory.Create);
+            Print();                                 // Hot [2,3,4] Warm [1] Cold []
+
+            lru.TryRemove(1);
+
+            lru.GetOrAdd(5, valueFactory.Create);
+            lru.GetOrAdd(6, valueFactory.Create);
+            lru.GetOrAdd(7, valueFactory.Create);
+            Print();                                // Hot [5,6,7] Warm [2,3,4] Cold []
+
+            lru.WarmCount.Should().Be(3);
+            lru.ColdCount.Should().Be(0);
+        }
+
+
+        [Fact]
+        public void WhenItemRemovedFromWarmAfterWarmupItIsEagerlyCycledOut()
+        {
+            for (int i = 0; i < lru.Capacity; i++)
+            {
+                lru.GetOrAdd(i, valueFactory.Create);
+            }
+
+            Print();                                    // Hot [6,7,8] Warm [1,2,3] Cold [0,4,5]
+            lru.Metrics.Value.Evicted.Should().Be(0);
+
+            lru.TryRemove(1);
+
+            lru.GetOrAdd(6, valueFactory.Create); // 6 -> W
+            lru.GetOrAdd(9, valueFactory.Create);
+
+            Print();                                    // Hot [7,8,9] Warm [2,3,6] Cold [0,4,5]
+
+            lru.Metrics.Value.Evicted.Should().Be(0);
+        }
+
         [Fact]
         public void WhenKeyDoesNotExistTryRemoveReturnsFalse()
         {
@@ -1343,6 +1391,14 @@ private void Warmup()
             lru.GetOrAdd(-8, valueFactory.Create);
             lru.GetOrAdd(-9, valueFactory.Create);
         }
+
+
+        private void Print()
+        {
+#if DEBUG
+            this.testOutputHelper.WriteLine(this.lru.FormatLruString());
+#endif
+        }
     }
 
     public class ConcurrentLruIntegrityChecker<K, V, I, P, T>

BitFaster.Caching/Lru/ConcurrentLruCore.cs

@@ -691,6 +691,11 @@ private void CycleDuringWarmup(int hotCount)
 
             if (this.warmQueue.TryDequeue(out var item))
             {
+                if (item.WasRemoved)
+                {
+                    return (ItemDestination.Remove, 0);
+                }
+
                 var where = this.itemPolicy.RouteWarm(item);
 
                 // When the warm queue is full, we allow an overflow of 1 item before redirecting warm items to cold.
@@ -754,7 +759,8 @@ private int LastWarmToCold()
 
             if (this.warmQueue.TryDequeue(out var item))
             {
-                return this.Move(item, ItemDestination.Cold, ItemRemovedReason.Evicted);
+                var destination = item.WasRemoved ? ItemDestination.Remove : ItemDestination.Cold;
+                return this.Move(item, destination, ItemRemovedReason.Evicted);
             }
             else
             {
@@ -818,6 +824,27 @@ IEnumerator IEnumerable.GetEnumerator()
             return ((ConcurrentLruCore<K, V, I, P, T>)this).GetEnumerator();
         }
 
+#if DEBUG
+        /// <summary>
+        /// Format the LRU as a string by converting all the keys to strings.
+        /// </summary>
+        /// <returns>The LRU formatted as a string.</returns>
+        public string FormatLruString()
+        {
+            var sb = new System.Text.StringBuilder();
+
+            sb.Append("Hot [");
+            sb.Append(string.Join(",", this.hotQueue.Select(n => n.Key.ToString())));
+            sb.Append("] Warm [");
+            sb.Append(string.Join(",", this.warmQueue.Select(n => n.Key.ToString())));
+            sb.Append("] Cold [");
+            sb.Append(string.Join(",", this.coldQueue.Select(n => n.Key.ToString())));
+            sb.Append(']');
+
+            return sb.ToString();
+        }
+#endif
+
         private static CachePolicy CreatePolicy(ConcurrentLruCore<K, V, I, P, T> lru)
         {
             var p = new Proxy(lru);