Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# SYS\$1UDF\$1LOG
<a name="SYS_UDF_LOG"></a>

Records system-defined error and warning messages generated during user-defined function (UDF) execution. 

SYS\$1UDF\$1LOG is visible only to superusers. For more information, see [Visibility of data in system tables and views](cm_chap_system-tables.md#c_visibility-of-data).

## Table columns
<a name="SYS_UDF_LOG-table-rows"></a>

[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/redshift/latest/dg/SYS_UDF_LOG.html)

## Sample queries
<a name="SYS_UDF_LOG-sample-queries"></a>

The following example shows how UDFs handle system-defined errors. The first block shows the definition for a UDF function that returns the inverse of an argument. When you run the function and provide a 0 as your argument, the function returns an error. The last statement returns the error message logged in SYS\$1UDF\$1LOG.

```
-- Create a function to find the inverse of a number.
CREATE OR REPLACE FUNCTION f_udf_inv(a int) 

RETURNS float 

IMMUTABLE AS $$return 1/a 

$$ LANGUAGE plpythonu; 

-- Run the function with 0 to create an error.
Select f_udf_inv(0); 

-- Query SYS_UDF_LOG to view the message.
Select query_id, record_time, message::varchar from sys_udf_log; 


query_id    |    record_time              |                 message
----------+----------------------------+-------------------------------------------------------
2211        | 2023-08-23 15:53:11.360538 |  ZeroDivisionError: integer division or modulo by zero line 2, in f_udf_inv\n return 1/a\n
```

The following example adds logging and a warning message to the UDF so that a divide by zero operation results in a warning message instead of stopping with an error message.

```
-- Create a function to find the inverse of a number and log a warning if you input 0.
CREATE OR REPLACE FUNCTION f_udf_inv_log(a int)
  RETURNS float IMMUTABLE
 AS $$ 
  import logging
  logger = logging.getLogger() #get root logger
  if a==0:
    logger.warning('You attempted to divide by zero.\nReturning zero instead of error.\n') 
    return 0
  else:
     return 1/a
$$ LANGUAGE plpythonu;

-- Run the function with 0 to trigger the warning.
Select f_udf_inv_log(0);

-- Query SYS_UDF_LOG to view the message.
Select query_id, record_time, message::varchar from sys_udf_log;

 query_id |        record_time         |                                    message
----------+----------------------------+-------------------------------------------------------------------------------
     0   | 2023-08-23 16:10:48.833503 | WARNING: You attempted to divide by zero.\nReturning zero instead of error.\n
```