Amazon Redshift Extract and Extract Refresh Fail with "error: assert"

Published: 21 Nov 2018
Last Modified Date: 18 Aug 2020


When refreshing or attempting to create an extract for Amazon Redshift, the process stops while fetching rows and throws an error:

          process:   padbmaster [pid=15943]
          location:  pg_utils.cpp:1347
          query:     2249
          context:   mod == -1 || (mod - VARHDRSZ) >= size - mod: 28, size: 52, VARHDRSZ: 4
          code:      1000
          error:  Assert
    excp-msg : [Amazon][RedShift ODBC] (30) Error occurred while trying to execute a query: ERROR:  Assert
    excp-type : 19DataSourceException



    dse-type : Unknown
    excp-type : 19DataSourceException
    excp-msg : ERROR: Assert;
        Error while executing the query


  • Tableau Desktop, all versions (using both Tableau Data Engine and Hyper engine)
  • Amazon Redshift
  • Extract


This issue is a known issue with Amazon Redshift relating to available memory for execution queues with options to address via Amazon Redshift/server hosting the database.
  1. Make sure that the user connecting to Amazon Redshift is part of an execution queue that has enough memory to run multiple queries at the same time, especially multiple larger queries.
  2. Increase Memory on the server hosting Redshift.



Redshift is failing to process the query from Tableau due to running out of working memory. 

Additional Information

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To read more about this specific issue, see the following Community Amazon forum post: ERROR: Assert step_save.cpp:466.

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