This document discusses debugging FME workflows. It provides an overview of common issues that can cause workflows to go off-rails, such as bad data, changes to data, or differences between FME Desktop and Server. It then outlines various tools for debugging in FME Workbench, including feature caching, data inspection, breakpoints, disabling objects, and logging. Tips are also provided for debugging scripts and isolating issues on FME Server versus Desktop. Best practices like versioning workflows are recommended to help with maintenance and troubleshooting.

1. Donʼt Bug Out!
The Ins and Outs of
Debugging FME Workflows

2. Meet the Presenters
Laura Wu
Director, Customer Support
Mark Stoakes
Senior Manager, FME Application Experts

3. Agenda
● When do things go off-the-rails?
● What does that look like?
● Tools for Debugging Workspaces
● Testing and Debugging in FME Server
● Itʼs a wrap

4. Ever developed a workflow, but
reached a roadblock of an
unexpected result or error message
you werenʼt sure how to resolve?

5. Type into the chat panel:
What’s your preferred tool for
troubleshooting your workspace?

6. Keywords Defined
Testing is the process of finding where errors occur in your workflow
Troubleshooting tracking down root-cause of issues
Debugging is the process to correct the errors found and isolated during testing and
troubleshooting
Go Off-The-Rails: to lose control and start to behave in a way that is not normal or
acceptable

7. When are things likely to go off-the-rails
● During workbench authoring
○ Testing out how transformers work
○ Experimenting with different approaches - should I use PointOnAreaOverlayer
or SpatialFilter or SpatialRelator?
● Bad data - oops! I thought all my data was perfect and consistent.
● When the data changes - different data brings different problems
○ For example you switch from your test data to your full dataset
● Differences between FME Desktop and FME Server
● FME errors / crashes - which never ever happens!

8. The symptoms?
● FME log:
○ ERROR
○ WARN
○ INFO
● Unexpected or incorrect results
● Rejected data
● No results
Error running translation.

9. Get Comfortable in FME Workbench
Tune FME Workbench:
● Modify your Toolbar
● Workbench window
layout - maximize your real
Estate
● Data Inspector vs. Visual Preview?
Use both…

10. Example

11. Tools for Troubleshooting in Workbench
● Feature Caching and Visual Preview 🔗
○ Collapse bookmarks for large workspaces
○ Caching doesnʼt always give the results you expect
○ Feature caching is not so good for very large datasets (and rasters)
● Data Inspector (and Visual Preview)
○ Graphics View
○ Table View
○ Feature Information
● Break Points 🔗
● Disable objects
● Workbench Search
● Transformers
○ fme_rejection_code

12. Data Inspection reminders…
● Data Inspector (and Visual Preview 🔗)
○ Graphics View
■ Background Maps
○ Table View
■ Columns / Search
○ Feature Information
■ Additional Attributes displayed
○ Display Control

13. More Tools for Troubleshooting in Workbench
● Logging - old school but effective
○ Reviewing your log file
○ Where is my log file?
<working folder><myworkspace>.log
○ Links to transformers
● Spatial Log File
○ <myworkspace>_log.ffs

14. More Tools for Troubleshooting in Workbench
● Logging - old school but effective
○ Reviewing your log file
○ Where is my log file?
<working folder><myworkspace>.log
○ Links to transformers
● Spatial Log File
○ <myworkspace>_log.ffs

15. More Tools for Troubleshooting in Workbench
● Logging - old school but effective
○ Reviewing your log file
○ Where is my log file?
<working folder><myworkspace>.log
○ Links to transformers
● Spatial Log File
○ <myworkspace>_log.ffs
● Debug Logging
○ FME Options > Translation > Log Message Filter > Log Debug
○ Extra detail for complex errors
○ Good for debugging with the HTTPCaller, SQLExecutor, SQLCreator

16. Simply your data: Reduce the volume of data
● Reduces run time
● Easier to find issues
Handy Transformers and Parameters for Simplifying Data
● TestFilter
● Sampler
● Max. Features to Read /
Feature Types to Read
Simplify your data when authoring

17. Where oh where did I make that change?
Workbench Search 🔗
Workspace Compare 🔗
● Compare the differences
between two workspaces
● Merge the changes

18. Isolating the issue
Make a Small Example
● Save as Template
○ Save with Cache
● Recorder / Player
● Sampler

19. Poll:
Have you seen any new troubleshooting
ideas that you might try?

20. Debugging Scripts
Python scripts can appear in various places in Workbench
● PythonCaller
● Startup/Shutdown Python Script
● Scripted Parameters
Script troubleshooting approaches:
● Python print statements
● Logger transformer
● Build complex scripts in a separate Python editor and import into FME

21. Many of the tips we have reviewed already also apply to FME Server
Debugging on FME Server
If a workspace doesnʼt run correctly on FME Server, try it on Desktop first
If it works on Desktop, but not FME Server, look for differences in the environments
● Permissions
● Dependencies
○ File paths
○ Missing transformers
○ Missing Python modules
○ Missing Web and Database Connections
○ Mismatched FME Versions
● Nondescript errors
○ Look at fmeprocessmonitorengine.log

22. Example

23. Even more thoughts on this topic…
Performance troubleshooting 🔗
Database Errors 🔗
● Errors can be buried in a transaction
○ The entire transaction is rolled back
○ Try Transaction Interval = 1
● Save As Workspace Template doesnʼt encompass database data
○ Recorder / Player
● Test SQL scripts in the appropriate database manager
● Database system log files

24. Some Best Practices
● Versioning workspaces
○ Publishing to FME Server & Commit
○ Workspace Compare
● Good workspace practices help with maintenance 🔗 🎓
○ Annotations / bookmarks
○ Look for repetition in your workspace - multiple readers / writers. Many
Testers
○ Should you rename Transformers

25. Summary
So weʼve covered:
● What it looks like when you do
encounter issues
● Tools for troubleshooting
workspaces
● Testing and debugging in FME
Server

26. Resources
● Feature Caching🔗
● Break Points🔗
● Visual Preview 🔗
● Workspace Compare 🔗
● Workbench Best Practices 🔗
● Debugging Workspaces on
FME Server 🔗

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28. Q&A

29. Thank you!
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