[jira] [Created] (FLINK-20606) sql client cannot create function using user classes from jar which specified by -j option

["akisaya (Jira)" <ji...@apache.org>]

akisaya created FLINK-20606:
-------------------------------

             Summary: sql client cannot create function using user classes from jar which specified by  -j option   
                 Key: FLINK-20606
                 URL: https://issues.apache.org/jira/browse/FLINK-20606
             Project: Flink
          Issue Type: Bug
          Components: Connectors / Hive, Table SQL / API, Table SQL / Client
    Affects Versions: 1.11.2, 1.12.0, 1.10.2
            Reporter: akisaya


I started a sql cli  with a hive catalog and specified a user jar file with -j option like this:
{code:java}
bin/sql-client.sh embedded -j /Users/akis/Desktop/flink-func/myfunc.jar
{code}
{color:#FF0000}when i tried to create a custom function using class from myfunc.jar，cli reported ClassNotFoundException.{color}

 
{code:java}
Flink SQL> use catalog myhive;

Flink SQL> create function myfunc1 as 'me.aki.flink.flinkudf.MyFunc';
[ERROR] Could not execute SQL statement. Reason:
java.lang.ClassNotFoundException: me.aki.flink.flinkudf.MyFunc
{code}
 

 

me.aki.flink.flinkudf.MyFunc is the identifier of udf，which defined like this

 
{code:java}
package me.aki.flink.flinkudf;

import org.apache.flink.table.functions.ScalarFunction;

public class MyFunc extends ScalarFunction {
    public String eval(String s) {
        return "myfunc_" + s;
    }
}
{code}
 

 

 

after walking through the related code, I believe this is a bug caused by wrong classloader

 

when using a hive catalog, flink will use  {color:#FF0000}CatalogFunctionImpl{color}  to wrap the function。 The

isGeneric() methed  uses {color:#FF0000}Class.forName(String clazzName){color} which will use a current classloader(classloader loads flink/lib) to determine the class。

 

however with -j option, user jar is set to the ExecutionContext and loaded by another userClassLoader

 

and the fix can be easy to pass a classloader to the Class.forName method.
{code:java}
ClassLoader cl = Thread.currentThread().getContextClassLoader();
Class c = Class.forName(className, true, cl);
{code}
after do such fix and build a new flink dist，create function behaves right

 

 

 

 

 

 

 

 



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