list.add(DefaultRelMetadataProvider.INSTANCE); hepPlanner.registerMetadataProviders(list); final RelMetadataProvider cachingMetaDataProvider = new CachingRelMetadataProvider( ChainedRelMetadataProvider.of(list), hepPlanner); volcanoPlanner.registerMetadataProviders(list); final RelMetadataProvider cachingMetaDataProvider = new CachingRelMetadataProvider( ChainedRelMetadataProvider.of(list), volcanoPlanner);