Default Refresh policy for ReactiveElasticsearchTemplate.

Original Pull Request #2124
Closes #2110

(cherry picked from commit acd7990)

Author: sothawo

src/main/asciidoc/reference/elasticsearch-migration-guide-4.3-4.4.adoc

@@ -28,6 +28,14 @@ Connections to Elasticsearch must be made using either the imperative `Elasticse
 In 4.3 two classes (`ElasticsearchAggregations` and `ElasticsearchAggregation`) had been moved to the `org.springframework.data.elasticsearch.core.clients.elasticsearch7` package in preparation for the integration of the new Elasticsearch client.
 The were moved back to the `org.springframework.data.elasticsearch.core` package as we keep the classes use the old Elasticsearch client where they were.
 
+=== Behaviour change
+
+The `ReactiveElasticsearchTemplate`, when created directly or by Spring Boot configuration had a default refresh policy of IMMEDIATE.
+This could cause performance issues on heavy indexing and was different than the default behaviour of Elasticsearch.
+This has been changed to that now the default refresh policy is NONE.
+When the
+`ReactiveElasticsearchTemplate` was provided by using the configuration like described in <<elasticsearch.clients.reactive>> the default refresh policy already was set to NONE.
+
 [[elasticsearch-migration-guide-4.3-4.4.new-clients]]
 == New Elasticsearch client
 

src/main/java/org/springframework/data/elasticsearch/core/AbstractReactiveElasticsearchTemplate.java

@@ -73,7 +73,7 @@ abstract public class AbstractReactiveElasticsearchTemplate
 	protected final SimpleElasticsearchMappingContext mappingContext;
 	protected final EntityOperations entityOperations;
 
-	protected @Nullable RefreshPolicy refreshPolicy = RefreshPolicy.IMMEDIATE;
+	protected @Nullable RefreshPolicy refreshPolicy = RefreshPolicy.NONE;
 	protected RoutingResolver routingResolver;
 
 	protected @Nullable ReactiveEntityCallbacks entityCallbacks;

src/test/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplateUnitTests.java

@@ -85,7 +85,7 @@ public void insertShouldUseDefaultRefreshPolicy() {
 				.as(StepVerifier::create) //
 				.verifyComplete();
 
-		assertThat(captor.getValue().getRefreshPolicy()).isEqualTo(WriteRequest.RefreshPolicy.IMMEDIATE);
+		assertThat(captor.getValue().getRefreshPolicy()).isEqualTo(WriteRequest.RefreshPolicy.NONE);
 	}
 
 	@Test // DATAES-504
@@ -170,7 +170,7 @@ public void deleteShouldUseDefaultRefreshPolicy() {
 				.as(StepVerifier::create) //
 				.verifyComplete();
 
-		assertThat(captor.getValue().getRefreshPolicy()).isEqualTo(WriteRequest.RefreshPolicy.IMMEDIATE);
+		assertThat(captor.getValue().getRefreshPolicy()).isEqualTo(WriteRequest.RefreshPolicy.NONE);
 	}
 
 	@Test // DATAES-504
@@ -198,7 +198,7 @@ public void deleteByShouldUseDefaultRefreshPolicy() {
 				.as(StepVerifier::create) //
 				.verifyComplete();
 
-		assertThat(captor.getValue().isRefresh()).isTrue();
+		assertThat(captor.getValue().isRefresh()).isFalse();
 	}
 
 	@Test // DATAES-504
@@ -207,13 +207,13 @@ public void deleteByShouldApplyRefreshPolicy() {
 		ArgumentCaptor<DeleteByQueryRequest> captor = ArgumentCaptor.forClass(DeleteByQueryRequest.class);
 		when(client.deleteBy(captor.capture())).thenReturn(Mono.empty());
 
-		template.setRefreshPolicy(RefreshPolicy.NONE);
+		template.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
 
 		template.delete(new StringQuery(QueryBuilders.matchAllQuery().toString()), Object.class, index) //
 				.as(StepVerifier::create) //
 				.verifyComplete();
 
-		assertThat(captor.getValue().isRefresh()).isFalse();
+		assertThat(captor.getValue().isRefresh()).isTrue();
 	}
 
 	@Test // DATAES-504