presto-phoenix/src/main/java/io/prestosql/plugin/phoenix/PhoenixMetadata.java/PhoenixMetadata/dropSchema
class PhoenixMetadata:    @Override
    public void dropSchema(ConnectorSession session, String schemaName)
    {
        if (DEFAULT_SCHEMA.equalsIgnoreCase(schemaName)) {
            throw new PrestoException(NOT_SUPPORTED, "Can't drop 'default' schema which maps to Phoenix empty schema");
        }
        phoenixClient.execute(session, format("DROP SCHEMA %s", getEscapedArgument(toMetadataCasing(session, schemaName))));
    }