Merge pull request #795 from tgruben/rank-bug

account for all same values in rank

cache.go

@@ -256,8 +256,10 @@ func (c *RankCache) recalculate() {
 	length := len(c.rankings)
 	c.stats.Gauge("RankCache", float64(length), 1.0)
 
+	var removeItems []BitmapPair // cached, ordered list
 	if length > int(c.maxEntries) {
 		c.thresholdValue = rankings[c.maxEntries].Count
+		removeItems = c.rankings[c.maxEntries:]
 		c.rankings = c.rankings[0:c.maxEntries]
 	} else {
 		c.thresholdValue = 1
@@ -269,10 +271,8 @@ func (c *RankCache) recalculate() {
 	// If size is larger than the threshold then trim it.
 	if len(c.entries) > c.thresholdBuffer {
 		c.stats.Count("cache.threshold", 1, 1.0)
-		for id, cnt := range c.entries {
-			if cnt <= c.thresholdValue {
-				delete(c.entries, id)
-			}
+		for _, pair := range removeItems {
+			delete(c.entries, pair.ID)
 		}
 	}
 }

cache_test.go

@@ -0,0 +1,35 @@
+// Copyright 2017 Pilosa Corp.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pilosa_test
+
+import (
+	"testing"
+
+	"github.com/pilosa/pilosa"
+)
+
+// Ensure a bitmap query can be executed.
+func TestCache_Rank(t *testing.T) {
+	cacheSize := uint32(3)
+	cache := pilosa.NewRankCache(cacheSize)
+	for i := 1; i < int(2*cacheSize); i++ {
+		cache.Add(uint64(i), 3)
+	}
+	cache.Recalculate()
+	if cache.Len() != int(cacheSize) {
+		t.Fatalf("unexpected cache Size: %d!=%d expected\n", cache.Len(), cacheSize)
+	}
+
+}