Set fetch size for Hibernate

Solves the N+1 problem for this size of dataset and the standard
repository queries. Much simpler than messing with the queries
or with the default fetch type.

Fixes #2157

Author: dsyer

src/main/resources/application.properties

@@ -10,6 +10,7 @@ spring.thymeleaf.mode=HTML
 spring.jpa.hibernate.ddl-auto=none
 spring.jpa.open-in-view=false
 spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategySnakeCaseImpl
+spring.jpa.properties.hibernate.default_batch_fetch_size=16
 
 # Internationalization
 spring.messages.basename=messages/messages

src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java

@@ -31,7 +31,7 @@
 import org.springframework.samples.petclinic.vet.VetRepository;
 import org.springframework.web.client.RestTemplate;
 
-@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, properties = "logging.level.sql=DEBUG")
 public class PetClinicIntegrationTests {
 
 	@LocalServerPort
@@ -56,6 +56,13 @@ void testOwnerDetails() {
 		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
 	}
 
+	@Test
+	void testOwnerList() {
+		RestTemplate template = builder.rootUri("http://localhost:" + port).build();
+		ResponseEntity<String> result = template.exchange(RequestEntity.get("/owners?lastName=").build(), String.class);
+		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
+	}
+
 	public static void main(String[] args) {
 		SpringApplication.run(PetClinicApplication.class, "--spring.docker.compose.lifecycle-management=NONE");
 	}