Debugging Guide for Workspaces

Liz Sanderson
Liz Sanderson
  • Updated


If you have encountered an issue with an FME workspace and are unable to resolve it, this guide will help narrow down the problem to its simplest form. This process should help solve the issue or ensure that you receive a timely solution from technical support.

The following diagram displays the process:



Step 1: Reproduce the Issue

“My workspace fails to write any data!"

Identify the exact steps that cause the issue to occur. This may be as simple as running a workspace or something more complex such as adding a series of transformers. You will need to be able to perform this procedure again in the steps below.


Step 2: Narrow the Focus

“My workspace seems to fail as there are no features exiting the Clipper’s Inside port!”

Think about the problem and the different objects present in the workspace. Are you reading, writing and/or transforming data? Try to narrow down the issue to something specific.

Important clues:

  • The feature count stops at a particular transformer
  • The log contains an error or warning about an object
  • The output dataset is unexpected or incorrect
  • Data fails to be read into the workspace
  • Data is not written

Helpful Tip

If you are encountering an issue when you run your workspace, use either of the following to help narrow down where the problem is coming from:

  • Run With Feature Caching: Runs the entire workflow and then allows you to inspect the data at any point in the workspace. This option is flexible but can take longer as you must process all the features first.
  • Run With Breakpoints: Stops the workflow at a specific breakpoint allowing you to visualize feature by feature within FME Workbench. This option is quick to use since it will stop at the first feature rather than running the entire workspace.

Once you have an idea of the general area where the problem exists, you can move on to the next step.


Step 3: Test Variables

“I’m going to try using only a single feature from the dataset”

Making small changes and testing is a great way to get to the source of an issue. For example, changing a workspace to read a smaller set of the same data, can test if a particular feature in that dataset is causing the issue. Below is a simple procedure to use:

Test Procedure:

  • Locate a variable that can be modified
  • Make a change to the variable
  • Run through the reproduction steps that cause the issue to occur
  • Record the outcome
  • Repeat (if the outcome is not different)

The following highlights example variables that can be utilized with Step 1 of the Test Procedure:

Variable Type Example Variable
  • Format
  • Feature Types to Read
  • Specific Parameters (Readers, Writers, Transformers)
  • Number of Features
  • Content of Features (Attribute Schema and Geometry)
  • FME Version
  • Installed Software and Operating System
  • Environment Variables
  • Network Access
  • User Account Permissions
  • Hardware

The following highlights example changes that can be used with Step 2 of the Test Procedure:

Change Type Example Change
  • Limit the number of features being read (See Max Features to Read )
  • Add a Tester to filter for specific types of data
  • Write using a different format
  • Change parameters back to the default setting
  • Remove and re-add the component
  • Recreate a small sample of the input data using a Creator transformer.
  • Write to a different location/database/schema
  • Drop database tables and have FME recreate them
  • Run your FME with your workspace on a separate system inside the network
  • Run your workspace on a system outside the network (if possible)
  • Test the workspace on a newer version of FME

Try anything that you think may lead to a different outcome!

Once you have made a change that creates a different output, proceed to the next step.

Note: If you were unable to make any changes that resulted in a different outcome and have exhausted every variable, proceed to Step 6: Go Direct to Source.


Step 4: Analyze the Outcome

“The simplified dataset was clipped! This means that a specific feature in my data is causing the problem not the clipper!”

This step is designed to either solve the issue or decide what to do next. Here is a flowchart of the process:


When a specific change alters the workspace outcome, it should help you point to a possible root cause for the problem.

Root Cause Examples:

  • A Specific Feature
  • Geometry Type
  • Incorrect Format Parameter
  • Spatial Reference (mismatched coordinate systems)
  • Operating System

Note: When the change seems related to a specific computer, you can Generate a System Information File for each environment to help narrow down the differences.

If the problem is still unresolved after your analysis then please proceed below.


(Optional) Step 5: Go Direct to the Source

In some cases, it may be possible that the issue is caused by something outside of the FME software. In this test, you should attempt to replicate the same functionality without using any FME software and see if the root cause can be discovered. This is an essential step when working with components such as databases, web applications, complex formats, and python scripts.

Direct to the Source Examples:
Issue: FME fails to read from an Esri Geodatabase.
Test: Use the ArcGIS for Desktop product to ensure the data can be read.

Issue: Error when connecting to a Web Site using the HTTPCaller.
Test: Try connecting through a web browser.

If the issue is still unresolved then proceed to the final step.


(Optional) Step 6: Contact Support

Please complete the following to ensure that you receive timely and correct technical assistance.

6a: Simplify the Workflow

The goal here is to create a very simple reproduction of the issue.

To simplify readers, do one of the following:

  • use Save As in Data Inspector to save a small sample back to the same format.
  • Recreate a small sample of the data using a Creator transformer.
  • Use the Recorder transformer to store your data and the Player transformer to play it back. This method is especially useful for database formats. See here for a step-by-step guide: Using the Recorder and Player.

If the issue requires that the specific reader format be present, then create a small subset of the data to submit with your case. To do this in FME, use the Clipper or Sampler transformer to create a new version of the data with a limited amount of features.

When a problem can be narrowed down to a specific transformer or series of transformers in the workflow, Place a Recorder transformer directly before this area and record the data. Then replace with a Player .

Replace writers with a Logger or Inspector transformer whenever possible.

Example of a simplified reproduction:

Note: After each simplification step, ensure that the problem still exists. If during this process you discover that the outcome has changed, go back to step 5 above and analyze the new information.


6b: Disable Unrelated Objects

Disable any components that are not related to the issue. These objects may be readers, writers and transformers within the workspace.

Run the workflow after each change to ensure that the problem still exists.

Problem: FME errors when reading data at runtime.
Process: Disable all transformers and writers from your workflow.

Problem: FME crashes within a StatisticsCalculator transformer
Process: Disable writers and transformers located before or after the StatisticsCalculator that do not cause the issue to occur. Attach a Logger transformer to the StatisticsCalculator to ensure the data flows through.


6c: Save as a Template File

Save your workspace as a template (.fmwt extension). This ensures that it can be run exactly the same way This file contains a copy of the workspace and all the data files necessary to run. A step-by-step guide can be found here: Creating a Template File.


6d: Send the Reproduction to Support

This step will create a request on the Safe Software support ticketing system.

Gather the following resources:

  • The workspace template
  • Log files
  • System Information Report (See here for information on how to generate this report)
  • Any supporting materials (Screenshots, video, documents)

Complete this form (attaching your files) in order to submit your issue to technical support.


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