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When Running Flow And Connecting to Amazon Redshift, Error "Output step error message: [GeneralFlowExecutionError] - System error." Is Consistently Occurring


Published: 29 Dec 2020
Last Modified Date: 26 May 2021

Issue

When running flows and connecting to Amazon Redshift, the flow failed with the below error displays in Performance of Flow Runs

Output step error message: [GeneralFlowExecutionError] - System error.
 

In the Run History tab of the issue flow, the following message displays when hovering over the error.

An error occurred when processing the flow. Try running the flow again.


The issue doesn't occur in Tableau Prep Builder 2020.3 and older.

Environment

  • Tableau Online
  • Amazon Redshift

Resolution

Following are possible workarounds for the above system error:
 
 [Amazon][Amazon Redshift] (30) Error occurred while trying to execute a query: [SQLState XX000] ERROR:  Invalid digit, Value '\ufffd', Pos 6, Type: Double
Instructions: Check the UNION steps, confirm if there are some values in Amazon Redshift that could not be converted directly from string to number. Try to Identifying the specific data, cleaning or filtering it, then run the flow again.
 
 [Amazon][Amazon Redshift] (30) Error occurred while trying to execute a query: [SQLState 42804] ERROR:  UNION types bigint and character varying cannot be matched 
Instructions: Check the UNION steps, confirm if there are some columns that have been converted to a numeric (bigint) type and the other is NULL. When unioning the result, the NULL is treated as a character, the error may occur due to the type mismatch. Try to convert NULL as a fixed value (e.g. 0), the issue can be prevented when both are numeric types.

Cause

This is related to the error from Amazon Redshift driver that deals with data type/values.
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