def index_cond(db, index):

    index = sql_gen.as_Table(index)

    module = util.root_module(db.db)

    if module == 'psycopg2':

        qual_index = sql_gen.Literal(index.to_str(db))

        return value(run_query(db, '''\

SELECT pg_get_expr(indpred, indrelid, true)

FROM pg_index

WHERE indexrelid = '''+qual_index.to_str(db)+'''::regclass

'''

            , cacheable=True, log_level=4))

    else: raise NotImplementedError()