public List<Database> getAllDatabases(final Duration duration) throws IOException {
        final List<Service> serviceList = getMetadataQueryService().listServices(Layer.VIRTUAL_DATABASE.name(), null);
        return serviceList.stream().map(service -> {
            Database database = new Database();
            database.setId(service.getId());
            database.setName(service.getName());
            return database;
        }).distinct().collect(Collectors.toList());
    }
@since 9.0.0 This query is replaced by {@link MetadataQueryV2}
oap-server/server-query-plugin/query-graphql-plugin/src/main/java/org/apache/skywalking/oap/query/graphql/resolver/MetadataQuery.java