Best practice in case data source on server not reachable
Hi there, we have an app running which has a data connection to a source from a shared drive. Now news are that the server this drive is located on will soon be shut down and there won't be any specific date named in advance when this will happen. Also, there isn't an alternative data storage available, so the app will likely not load for a couple of days or even weeks. We want to make sure that when the shared drive is shut down, the latest data loaded for the report is displayed without any error messages so that the report can still be used knowing that only the data version is a couple of days old. So my questions are:
what happens if the source becomes unavailable - will the report still display the latest data or any error messages?
will the task reload automatically be disabled when the reload of the app fails? I think that happens in Power BI in case the reload fails 5 times or so, that's why I'm asking
What is the best practice to handle this kind of problem? Maybe additional error handling? Is there any source I could learn from?
Unless you've explicitly changed it, Qlik's default behavior is to stop running and keep the old data when a reload fails. No steps would be needed for this. Nothing should happen to the task (but you can disable it manually if you'd prefer for it to not run until instructed otherwise).
You can use the ErrorMode variable in your script to tell Qlik how to handle issues when running, but in the case you're describing it doesn't seem like this is actually necessary.
Sounds like you are on premise, there the reload will fail and the app keeps the previous data. On the other hand if you are on SaaS the reload will be disabled after failing a number of times in a row. Note that if the app has several sources of data neither will the other data be updated even though it is available. A failure will stop the whole reload. Way around that would be to have a separate extract job fetching the data from the fileshare to a local qvd-file. Then have an independent reload of your app reading from the local qvd-file. You could stop the reload from failing using Error handling in Qlik but then you would loose the old data. My recommended solution would be to have an independent task fetching the data from shared drive to local qvd-file.
