diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/HitBooleanTable.java b/src/main/java/com/googlesource/gerrit/plugins/task/HitBooleanTable.java
index 39365cb..adce341 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/HitBooleanTable.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/HitBooleanTable.java
@@ -27,7 +27,7 @@
     public long size;
     public int numberOfRows;
     public int numberOfColumns;
-    public long sumNanosecondsLoading;
+    public Long sumNanosecondsLoading;
   }
 
   protected Statistics statistics;
@@ -49,6 +49,9 @@
     if (statistics == null) {
       return StopWatch.DISABLED;
     }
+    if (statistics.sumNanosecondsLoading == null) {
+      statistics.sumNanosecondsLoading = 0L;
+    }
     return new StopWatch.Enabled().setNanosConsumer(ns -> statistics.sumNanosecondsLoading += ns);
   }
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/HitHashMap.java b/src/main/java/com/googlesource/gerrit/plugins/task/HitHashMap.java
index 7a23fc6..82cedf7 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/HitHashMap.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/HitHashMap.java
@@ -26,7 +26,7 @@
   public static class Statistics {
     public long hits;
     public int size;
-    public long sumNanosecondsLoading;
+    public Long sumNanosecondsLoading;
     public List<Object> elements;
   }
 
@@ -65,6 +65,19 @@
   public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
     V v = get(key);
     if (v == null) {
+      v = mappingFunction.apply(key);
+      if (v != null) {
+        put(key, v);
+      }
+    }
+    return v;
+  }
+
+  @Override
+  @SuppressWarnings("try")
+  public V computeIfAbsentTimed(K key, Function<? super K, ? extends V> mappingFunction) {
+    V v = get(key);
+    if (v == null) {
       try (StopWatch stopWatch = createLoadingStopWatch()) {
         v = mappingFunction.apply(key);
       }
@@ -144,6 +157,9 @@
     if (statistics == null) {
       return StopWatch.DISABLED;
     }
+    if (statistics.sumNanosecondsLoading == null) {
+      statistics.sumNanosecondsLoading = 0L;
+    }
     return new StopWatch.Enabled().setNanosConsumer(ns -> statistics.sumNanosecondsLoading += ns);
   }
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/StatisticsMap.java b/src/main/java/com/googlesource/gerrit/plugins/task/StatisticsMap.java
index 4ae8857..7c401a9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/StatisticsMap.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/StatisticsMap.java
@@ -15,5 +15,10 @@
 package com.googlesource.gerrit.plugins.task;
 
 import java.util.Map;
+import java.util.function.Function;
 
-public interface StatisticsMap<K, V> extends Map<K, V>, TracksStatistics {}
+public interface StatisticsMap<K, V> extends Map<K, V>, TracksStatistics {
+  V computeIfAbsentTimed(K key, Function<? super K, ? extends V> mappingFunction);
+
+  StopWatch createLoadingStopWatch();
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java b/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
index 26f7260..4a7d0fd 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
@@ -86,7 +86,7 @@
   protected final NodeList root = new NodeList();
   protected final Provider<ChangeQueryBuilder> changeQueryBuilderProvider;
   protected final Provider<ChangeQueryProcessor> changeQueryProcessorProvider;
-  protected final HitHashMap<String, List<ChangeData>> changesByNamesFactoryQuery =
+  protected final StatisticsMap<String, List<ChangeData>> changesByNamesFactoryQuery =
       new HitHashMap<>();
   protected final StatisticsMap<SubSectionKey, List<Task>> definitionsBySubSection =
       new HitHashMapOfCollection<>();
@@ -264,7 +264,7 @@
         if (!isChange()) {
           return cachedNodes = nodes;
         }
-        definitionsBySubSection.computeIfAbsent(
+        definitionsBySubSection.computeIfAbsentTimed(
             task.key().subSection(),
             k -> nodes.stream().map(n -> n.getDefinition()).collect(toList()));
       } else {