HHH-17689 Cache SQL statement for unique key lookup

Author: beikov

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/SingleUniqueKeyEntityLoaderStandard.java

@@ -41,6 +41,8 @@
 public class SingleUniqueKeyEntityLoaderStandard<T> implements SingleUniqueKeyEntityLoader<T> {
 	private final EntityMappingType entityDescriptor;
 	private final ModelPart uniqueKeyAttribute;
+	private final JdbcParametersList jdbcParameters;
+	private final JdbcOperationQuerySelect jdbcSelect;
 
 	public SingleUniqueKeyEntityLoaderStandard(
 			EntityMappingType entityDescriptor,
@@ -52,23 +54,9 @@ public SingleUniqueKeyEntityLoaderStandard(
 		else {
 			this.uniqueKeyAttribute = uniqueKeyAttribute;
 		}
-	}
-
-	@Override
-	public EntityMappingType getLoadable() {
-		return entityDescriptor;
-	}
-
-	@Override
-	public T load(
-			Object ukValue,
-			LockOptions lockOptions,
-			Boolean readOnly,
-			SharedSessionContractImplementor session) {
-		final SessionFactoryImplementor sessionFactory = session.getFactory();
 
-		// todo (6.0) : cache the SQL AST and JdbcParameters
-		JdbcParametersList.Builder builder = JdbcParametersList.newBuilder();
+		final SessionFactoryImplementor sessionFactory = entityDescriptor.getEntityPersister().getFactory();
+		final JdbcParametersList.Builder builder = JdbcParametersList.newBuilder();
 		final SelectStatement sqlAst = LoaderSelectBuilder.createSelectByUniqueKey(
 				entityDescriptor,
 				Collections.emptyList(),
@@ -83,7 +71,23 @@ public T load(
 		final JdbcServices jdbcServices = sessionFactory.getJdbcServices();
 		final JdbcEnvironment jdbcEnvironment = jdbcServices.getJdbcEnvironment();
 		final SqlAstTranslatorFactory sqlAstTranslatorFactory = jdbcEnvironment.getSqlAstTranslatorFactory();
-		JdbcParametersList jdbcParameters = builder.build();
+		this.jdbcParameters = builder.build();
+		this.jdbcSelect = sqlAstTranslatorFactory.buildSelectTranslator( sessionFactory, sqlAst )
+				.translate( JdbcParameterBindings.NO_BINDINGS, QueryOptions.NONE );
+	}
+
+	@Override
+	public EntityMappingType getLoadable() {
+		return entityDescriptor;
+	}
+
+	@Override
+	public T load(
+			Object ukValue,
+			LockOptions lockOptions,
+			Boolean readOnly,
+			SharedSessionContractImplementor session) {
+		final SessionFactoryImplementor sessionFactory = session.getFactory();
 
 		final JdbcParameterBindings jdbcParameterBindings = new JdbcParameterBindingsImpl( jdbcParameters.size() );
 		int offset = jdbcParameterBindings.registerParametersForEachJdbcValue(
@@ -93,9 +97,6 @@ public T load(
 				session
 		);
 		assert offset == jdbcParameters.size();
-		final JdbcOperationQuerySelect jdbcSelect = sqlAstTranslatorFactory.buildSelectTranslator( sessionFactory, sqlAst )
-				.translate( jdbcParameterBindings, QueryOptions.NONE );
-
 		final List<Object> list = sessionFactory.getJdbcServices().getJdbcSelectExecutor().list(
 				jdbcSelect,
 				jdbcParameterBindings,