hibernate/hibernate-orm · error · IllegalArgumentException

Unsupported aggregate SQL type: {}

Error message

Unsupported aggregate SQL type: {}

What it means

Error "Unsupported aggregate SQL type: {}" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/dialect/aggregate/SpannerPostgreSQLAggregateSupport.java:33

import static org.hibernate.type.SqlTypes.JSON;
import static org.hibernate.type.SqlTypes.JSON_ARRAY;

/***
 * Spanner supports only JSON aggregation. It doesn't support XML or STRUCT aggregation
 */
public class SpannerPostgreSQLAggregateSupport extends PostgreSQLAggregateSupport {

	public static final AggregateSupport INSTANCE = new SpannerPostgreSQLAggregateSupport();

	@Override
	public String aggregateComponentCustomReadExpression(String template, String placeholder, String aggregateParentReadExpression, String columnExpression, int aggregateColumnTypeCode, SqlTypedMapping column, TypeConfiguration typeConfiguration) {
		return switch ( aggregateColumnTypeCode ) {
			case JSON_ARRAY, JSON ->
					super.aggregateComponentCustomReadExpression( template, placeholder, aggregateParentReadExpression,
							columnExpression, aggregateColumnTypeCode, column, typeConfiguration );
			default ->
					throw new IllegalArgumentException( "Unsupported aggregate SQL type: " + aggregateColumnTypeCode );
		};
	}

	@Override
	public String aggregateComponentAssignmentExpression(String aggregateParentAssignmentExpression, String columnExpression, int aggregateColumnTypeCode, Column column) {
		return switch ( aggregateColumnTypeCode ) {
			case JSON, JSON_ARRAY ->
					super.aggregateComponentAssignmentExpression( aggregateParentAssignmentExpression, columnExpression,
							aggregateColumnTypeCode, column );
			default ->
					throw new IllegalArgumentException( "Unsupported aggregate SQL type: " + aggregateColumnTypeCode );
		};
	}

	@Override
	public boolean requiresAggregateCustomWriteExpressionRenderer(int aggregateSqlTypeCode) {
		return aggregateSqlTypeCode == JSON;
	}

View on GitHub (pinned to fad1729dce)

Solutions

1. Map the aggregate column with a supported SQL type.
2. Avoid the unsupported aggregate type on Spanner.

When it happens

Trigger: Triggered when the application calls a Hibernate dialect feature that the configured database dialect cannot provide: Unsupported aggregate SQL type (Spanner PostgreSQL).

Common situations: Common when running against a database whose dialect lacks this capability, when a mapping or HQL/Criteria query requests unsupported functionality, or when the wrong dialect is configured for the database in use. Error: Unsupported aggregate SQL type (Spanner PostgreSQL).

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/2f4b7e8b214c85dd. Report an issue: GitHub.