From 598cc46bae089b95f34d0e5cc02b4f25c73c064f Mon Sep 17 00:00:00 2001
From: Roman Leventov <leventov.ru@gmail.com>
Date: Fri, 25 Aug 2017 14:30:39 -0500
Subject: [PATCH] Replace HashMap with Obj2IntMap in StringDimensionIndexer;
 Small optimization in StringDimensionMergerV9 (#4721)

---
 .../io/druid/segment/StringDimensionIndexer.java   | 14 +++++++-------
 .../io/druid/segment/StringDimensionMergerV9.java  |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/processing/src/main/java/io/druid/segment/StringDimensionIndexer.java b/processing/src/main/java/io/druid/segment/StringDimensionIndexer.java
index 30a14dcd5bd..6a7ab2b9ada 100644
--- a/processing/src/main/java/io/druid/segment/StringDimensionIndexer.java
+++ b/processing/src/main/java/io/druid/segment/StringDimensionIndexer.java
@@ -23,7 +23,6 @@ import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
 import com.google.common.base.Strings;
 import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
 import com.google.common.primitives.Ints;
 import io.druid.collections.bitmap.BitmapFactory;
 import io.druid.collections.bitmap.MutableBitmap;
@@ -44,6 +43,8 @@ import io.druid.segment.incremental.IncrementalIndex;
 import io.druid.segment.incremental.IncrementalIndexStorageAdapter;
 import it.unimi.dsi.fastutil.ints.IntArrays;
 import it.unimi.dsi.fastutil.ints.IntIterator;
+import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2IntRBTreeMap;
 import it.unimi.dsi.fastutil.objects.Object2IntSortedMap;
 
@@ -53,7 +54,6 @@ import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Iterator;
 import java.util.List;
-import java.util.Map;
 import java.util.function.Function;
 
 public class StringDimensionIndexer implements DimensionIndexer<Integer, int[], String>
@@ -65,7 +65,7 @@ public class StringDimensionIndexer implements DimensionIndexer<Integer, int[],
     private String minValue = null;
     private String maxValue = null;
 
-    private final Map<String, Integer> valueToId = Maps.newHashMap();
+    private final Object2IntMap<String> valueToId = new Object2IntOpenHashMap<>();
 
     private final List<String> idToValue = Lists.newArrayList();
     private final Object lock;
@@ -73,13 +73,13 @@ public class StringDimensionIndexer implements DimensionIndexer<Integer, int[],
     public DimensionDictionary()
     {
       this.lock = new Object();
+      valueToId.defaultReturnValue(-1);
     }
 
     public int getId(String value)
     {
       synchronized (lock) {
-        final Integer id = valueToId.get(Strings.nullToEmpty(value));
-        return id == null ? -1 : id;
+        return valueToId.getInt(Strings.nullToEmpty(value));
       }
     }
 
@@ -108,8 +108,8 @@ public class StringDimensionIndexer implements DimensionIndexer<Integer, int[],
     {
       String value = Strings.nullToEmpty(originalValue);
       synchronized (lock) {
-        Integer prev = valueToId.get(value);
-        if (prev != null) {
+        int prev = valueToId.getInt(value);
+        if (prev >= 0) {
           return prev;
         }
         final int index = size();
diff --git a/processing/src/main/java/io/druid/segment/StringDimensionMergerV9.java b/processing/src/main/java/io/druid/segment/StringDimensionMergerV9.java
index 296e911d187..887620c36ac 100644
--- a/processing/src/main/java/io/druid/segment/StringDimensionMergerV9.java
+++ b/processing/src/main/java/io/druid/segment/StringDimensionMergerV9.java
@@ -583,7 +583,7 @@ public class StringDimensionMergerV9 implements DimensionMergerV9<int[]>
         @Override
         public int skip(int n)
         {
-          return IntIteratorUtils.skip(this, n);
+          return IntIteratorUtils.skip(baseIterator, n);
         }
       };
     }