Remove QUERY_AND_FETCH search type (#22996)

`QUERY_AND_FETCH` has been treated as an internal optimization for 2 major
versions. This commit removes the search type and it's implementation details and
folds the optimization in the case of a single shard into the search controller such
that every search with a single shard (non DFS) will receive this optimization.

3 files changed, 24 insertions, 24 deletions

diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
index 96fbf17480..9af28806fe 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/DiversifiedSamplerIT.java
@@ -99,7 +99,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         // Tests that we can refer to nested elements under a sample in a path
         // statement
         boolean asc = randomBoolean();
-        SearchResponse response = client().prepareSearch("test").setTypes("book").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("test").setTypes("book").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .addAggregation(terms("genres")
                         .field("genre")
                         .order(Terms.Order.aggregation("sample>max_price.value", asc))
@@ -132,7 +132,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
         sampleAgg.subAggregation(terms("authors").field("author"));
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy"))
                 .setFrom(0).setSize(60)
                 .addAggregation(sampleAgg)
@@ -158,7 +158,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         sampleAgg.subAggregation(terms("authors").field("author"));
 
         rootTerms.subAggregation(sampleAgg);
-        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .addAggregation(rootTerms).execute().actionGet();
         assertSearchResponse(response);
         Terms genres = response.getAggregations().get("genres");
@@ -188,7 +188,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         sampleAgg.subAggregation(terms("genres").field("genre"));
 
         rootSample.subAggregation(sampleAgg);
-        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH).addAggregation(rootSample)
+        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_THEN_FETCH).addAggregation(rootSample)
                 .execute().actionGet();
         assertSearchResponse(response);
         Sampler genreSample = response.getAggregations().get("genreSample");
@@ -213,7 +213,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         DiversifiedAggregationBuilder sampleAgg = new DiversifiedAggregationBuilder("sample").shardSize(100).field("author")
                 .maxDocsPerValue(1);
         sampleAgg.subAggregation(terms("authors").field("author"));
-        SearchResponse response = client().prepareSearch("idx_unmapped_author", "test").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("idx_unmapped_author", "test").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg)
                 .execute().actionGet();
         assertSearchResponse(response);
@@ -229,7 +229,7 @@ public class DiversifiedSamplerIT extends ESIntegTestCase {
         DiversifiedAggregationBuilder sampleAgg = new DiversifiedAggregationBuilder("sample").shardSize(100);
         sampleAgg.field("author").maxDocsPerValue(MAX_DOCS_PER_AUTHOR).executionHint(randomExecutionHint());
         sampleAgg.subAggregation(terms("authors").field("author"));
-        SearchResponse response = client().prepareSearch("idx_unmapped", "idx_unmapped_author").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("idx_unmapped", "idx_unmapped_author").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg).execute().actionGet();
         assertSearchResponse(response);
         Sampler sample = response.getAggregations().get("sample");
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
index 980d792013..f87b98bc87 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SamplerIT.java
@@ -95,7 +95,7 @@ public class SamplerIT extends ESIntegTestCase {
         // Tests that we can refer to nested elements under a sample in a path
         // statement
         boolean asc = randomBoolean();
-        SearchResponse response = client().prepareSearch("test").setTypes("book").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("test").setTypes("book").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .addAggregation(terms("genres")
                         .field("genre")
                         .order(Terms.Order.aggregation("sample>max_price.value", asc))
@@ -125,7 +125,7 @@ public class SamplerIT extends ESIntegTestCase {
     public void testSimpleSampler() throws Exception {
         SamplerAggregationBuilder sampleAgg = sampler("sample").shardSize(100);
         sampleAgg.subAggregation(terms("authors").field("author"));
-        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_AND_FETCH)
+        SearchResponse response = client().prepareSearch("test").setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy")).setFrom(0).setSize(60).addAggregation(sampleAgg).execute().actionGet();
         assertSearchResponse(response);
         Sampler sample = response.getAggregations().get("sample");
@@ -143,7 +143,7 @@ public class SamplerIT extends ESIntegTestCase {
         SamplerAggregationBuilder sampleAgg = sampler("sample").shardSize(100);
         sampleAgg.subAggregation(terms("authors").field("author"));
         SearchResponse response = client().prepareSearch("idx_unmapped")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy"))
                 .setFrom(0).setSize(60)
                 .addAggregation(sampleAgg)
@@ -160,7 +160,7 @@ public class SamplerIT extends ESIntegTestCase {
         SamplerAggregationBuilder sampleAgg = sampler("sample").shardSize(100);
         sampleAgg.subAggregation(terms("authors").field("author"));
         SearchResponse response = client().prepareSearch("idx_unmapped", "test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("genre", "fantasy"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(sampleAgg)
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsIT.java
index 7e460afd4f..bff7471e86 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsIT.java
@@ -127,7 +127,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testStructuredAnalysis() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("fact_category").executionHint(randomExecutionHint())
@@ -143,7 +143,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
     public void testStructuredAnalysisWithIncludeExclude() throws Exception {
         long[] excludeTerms = { MUSIC_CATEGORY };
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "paul"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("fact_category").executionHint(randomExecutionHint())
@@ -223,7 +223,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testUnmapped() throws Exception {
         SearchResponse response = client().prepareSearch("idx_unmapped")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("fact_category").executionHint(randomExecutionHint())
@@ -237,7 +237,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testTextAnalysis() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description").executionHint(randomExecutionHint())
@@ -251,7 +251,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testTextAnalysisGND() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description").executionHint(randomExecutionHint()).significanceHeuristic(new GND(true))
@@ -265,7 +265,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testTextAnalysisChiSquare() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description").executionHint(randomExecutionHint()).significanceHeuristic(new ChiSquare(false,true))
@@ -280,7 +280,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
     public void testTextAnalysisPercentageScore() throws Exception {
         SearchResponse response = client()
                 .prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0)
                 .setSize(60)
@@ -299,7 +299,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
         // We search for the name of a snowboarder but use music-related content (fact_category:1)
         // as the background source of term statistics.
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description")
@@ -323,7 +323,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testFilteredAnalysis() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "weller"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description")
@@ -348,7 +348,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
                 { "paul", "smith" },
                 { "craig", "kelly", "terje", "haakonsen", "burton" }};
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .addAggregation(terms("myCategories").field("fact_category").minDocCount(2)
                         .subAggregation(
                                    significantTerms("mySignificantTerms").field("description")
@@ -373,7 +373,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testPartiallyUnmapped() throws Exception {
         SearchResponse response = client().prepareSearch("idx_unmapped", "test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms").field("description")
@@ -388,7 +388,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testPartiallyUnmappedWithFormat() throws Exception {
         SearchResponse response = client().prepareSearch("idx_unmapped", "test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(boolQuery().should(termQuery("description", "the")).should(termQuery("description", "terje")))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms")
@@ -425,7 +425,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testDefaultSignificanceHeuristic() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms")
@@ -442,7 +442,7 @@ public class SignificantTermsIT extends ESIntegTestCase {
 
     public void testMutualInformation() throws Exception {
         SearchResponse response = client().prepareSearch("test")
-                .setSearchType(SearchType.QUERY_AND_FETCH)
+                .setSearchType(SearchType.QUERY_THEN_FETCH)
                 .setQuery(new TermQueryBuilder("description", "terje"))
                 .setFrom(0).setSize(60).setExplain(true)
                 .addAggregation(significantTerms("mySignificantTerms")