Generating Error Snapshots with LoadRunner Controller

LoadRunner Controller throws up errors here and there almost all the time; 99% of these errors are due to either scripting problems or code changes (the other 1% are out of memory exception errors ;))

The errors generated in the Controller are usually enough to figure out what the problem is, however there are times where the errors generated leave one searching for clues like a scavenger hunt.

Then I came across this option in the Controller… “Generate snapshot on error“… hmm, this looks like it could prove very useful for web testing.
Indeed it did. Turns out that every-time an error is encountered in the Controller, a snap-shot of the page the error was encountered on will be saved and stored in the results folder in .html format.

This option can be found in the run time settings and needs to be configured for each script in the Controller:

Miscellaneous tab in the run time settings

The screenshot below shows a further setting related to the snapshoting facility  the ability to save snapshots locally which apparently makes the snapshots more accurate.

Preferences tab in the script run time settings

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4 Responses to Generating Error Snapshots with LoadRunner Controller

  1. jimmy says:

    It would be more helpful if you figured out a way to FORCE A SNAPSHOT FROM WITHIN A SCRIPT. Many times, I use web_reg_find to capture errors and continue. No snapshots are generated, because no error is generated.

    • E Mikail T says:

      Hi Jimmy,
      There is an option in the run time settings which might be useful in your case: ‘continue on error‘ (see the first screen-shot in this article).

      Also note the following in the reference guide:
      “It is not recommended to enable both the Continue on Error and Generate Snapshot on Error options in a load test environment. This configuration may adversely affect the Vusers’ performance”

      As for a specific function; I had a quick check of the VUGen reference guide and did not see anything that would allow you to force a snapshot in the script it self.

      As a side note, you should only really be using the snapshot feature for troubleshooting as it can generate a lot of overhead and have a negative effect on the VUsers.

  2. Subhasis Behera says:

    Hi,
    If you select generate snapshot on error then it may create problem while collating the results in controller.If failure rate is more and you are selecting generate snapshots on error then you may face problem while collating result.So better avoid to select generate snapshots option in runtime settings , if you are running with more number of users.

    • E Mikail T says:

      Hi Subhasis,
      I agree with you – this option should only be used if you are trying to diagnose a problem.

      Running a working scenario with this option could give you undesired results if you start to receive a lot of errors under load; especially with many users as you stated.

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