KNOWLEDGE BASE

When Using "Edit Value" or "Group Values" to Replace Values in Many Fields, Log Files Grow Large and Machine Might Be Hung


Published: 17 Sep 2020
Last Modified Date: 16 Oct 2020

Issue

When using "Edit Value" or "Group Values" (Group and Replace in previous versions) to replace values in a lot of fields, log files grow very large (up to 30GB in some cases) and sometimes causes the machine to hung. 

Environment

  • Tableau Prep Builder 2019.4.1 or later

Resolution

Workaround
Use calculation field instead of "Replace".

For example:
To replace null with zero - Create a calculation field and use ZN().
To replace 'AAA' with 'Good' - Create a calculation filed and use "IF [column] = 'AAA' THEN 'Good' ELSE [column] END"

Cause

The log files can grow large for following reasons:
1. The query is very large.
2. It takes longer to execute and process a large number of requests that poll for the status of the execution, which causes a lot of records to be added in the logs.
Remap works better for modifying a large number of values in a single column, but not optimized for replacing values across many columns.
 
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