From 8b8ca0d7fce8721f292d662efe0d310694dad0aa Mon Sep 17 00:00:00 2001
From: Gian Merlino <gianmerlino@gmail.com>
Date: Mon, 22 Jul 2024 21:17:11 -0700
Subject: [PATCH] DimFilterUtils: Exit filterShards early when filter is null.
 (#16774)

When the filter is null, there is no need to run the converter on
all the input objects.
---
 .../org/apache/druid/query/filter/DimFilterUtils.java    | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/processing/src/main/java/org/apache/druid/query/filter/DimFilterUtils.java b/processing/src/main/java/org/apache/druid/query/filter/DimFilterUtils.java
index dad5cfd98b3..ff863f764b7 100644
--- a/processing/src/main/java/org/apache/druid/query/filter/DimFilterUtils.java
+++ b/processing/src/main/java/org/apache/druid/query/filter/DimFilterUtils.java
@@ -20,6 +20,7 @@
 package org.apache.druid.query.filter;
 
 import com.google.common.base.Function;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.RangeSet;
 import org.apache.druid.query.planning.DataSourceAnalysis;
 import org.apache.druid.timeline.partition.ShardSpec;
@@ -116,13 +117,19 @@ public class DimFilterUtils
       final Map<String, Optional<RangeSet<String>>> dimensionRangeCache
   )
   {
+    if (dimFilter == null) {
+      // ImmutableSet retains order from "input".
+      return ImmutableSet.copyOf(input);
+    }
+
+    // LinkedHashSet retains order from "input".
     Set<T> retSet = new LinkedHashSet<>();
 
     for (T obj : input) {
       ShardSpec shard = converter.apply(obj);
       boolean include = true;
 
-      if (dimFilter != null && shard != null) {
+      if (shard != null) {
         Map<String, RangeSet<String>> filterDomain = new HashMap<>();
         List<String> dimensions = shard.getDomainDimensions();
         for (String dimension : dimensions) {