[INTERNAL_ERROR]Could not find function XXX, arg Int32 return Nullable(Int32)

[zhangm365]

I want to add a new type udf, that is python udf. The SQL syntax is:

CREATE FUNCTION python_echo(int) RETURNS int PROPERTIES (
    "file"="inline",
    "symbol"="echo",
    "type"="PYTHON_UDF"
)
AS
$$
" 
def echo(x):
	return x
"
$$
;

Then, I can show functions:

mysql> show functions;
+---------------+
| Function Name |
+---------------+
| addone        |
| python_echo   |
+---------------+
2 rows in set (0.01 sec)

But, I run the select query, the error is:

[INTERNAL_ERROR]Could not find function python_echo, arg Int32 return Nullable(Int32) .

And the error function is at Coordinator.java::waitPipelineRpc