From 7dc41a3b831a2bdf1b3303a05e306a84d42cae56 Mon Sep 17 00:00:00 2001
From: Alan Woodward <romseygeek@apache.org>
Date: Mon, 24 Feb 2020 14:28:51 +0000
Subject: [PATCH] Use BoostQuery rather than FunctionScoreQuery for query-time
 indices_boost (#52272)

This is a trivial change, but it should result in a slightly more efficient query boost.
---
 .../java/org/elasticsearch/search/DefaultSearchContext.java  | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/server/src/main/java/org/elasticsearch/search/DefaultSearchContext.java b/server/src/main/java/org/elasticsearch/search/DefaultSearchContext.java
index a096364d9ba..ce6fcda788c 100644
--- a/server/src/main/java/org/elasticsearch/search/DefaultSearchContext.java
+++ b/server/src/main/java/org/elasticsearch/search/DefaultSearchContext.java
@@ -21,6 +21,7 @@ package org.elasticsearch.search;
 
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.MatchNoDocsQuery;
@@ -32,8 +33,6 @@ import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.lease.Releasables;
 import org.elasticsearch.common.lucene.search.Queries;
-import org.elasticsearch.common.lucene.search.function.FunctionScoreQuery;
-import org.elasticsearch.common.lucene.search.function.WeightFactorFunction;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.index.IndexService;
@@ -254,7 +253,7 @@ final class DefaultSearchContext extends SearchContext {
             parsedQuery(ParsedQuery.parsedMatchAllQuery());
         }
         if (queryBoost() != AbstractQueryBuilder.DEFAULT_BOOST) {
-            parsedQuery(new ParsedQuery(new FunctionScoreQuery(query(), new WeightFactorFunction(queryBoost)), parsedQuery()));
+            parsedQuery(new ParsedQuery(new BoostQuery(query(), queryBoost), parsedQuery()));
         }
         this.query = buildFilteredQuery(query);
         if (rewrite) {