SYS_UDF_LOG

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

SYS_UDF_LOG is visible only to superusers. For more information, see Visibility of data in system tables and views.

Table columns

Column name	Data type	Description
query_id	bigint	The query identifier.
function_name	text	The name of the user-defined function.
record_time	timestamp	The time that the record was created.
sequence	integer	The sequence of a single log message.
message	text	The log message text.

Sample queries

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_UDF_LOG.

-- 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