presto-main/src/main/java/io/prestosql/metadata/MetadataManager.java/MetadataManager/getSystemTable
class MetadataManager:    @Override
    public Optional<SystemTable> getSystemTable(Session session, QualifiedObjectName tableName)
    {
        requireNonNull(session, "session is null");
        requireNonNull(tableName, "table is null");

        Optional<CatalogMetadata> catalog = getOptionalCatalogMetadata(session, tableName.getCatalogName());
        if (catalog.isPresent()) {
            CatalogMetadata catalogMetadata = catalog.get();

            // we query only main connector for runtime system tables
            CatalogName catalogName = catalogMetadata.getCatalogName();
            ConnectorMetadata metadata = catalogMetadata.getMetadataFor(catalogName);

            return metadata.getSystemTable(session.toConnectorSession(catalogName), tableName.asSchemaTableName());
        }
        return Optional.empty();
    }