SyntheticTimeoutException: what is this, how to suppress or ignore them?

[digital88]

Hi.

I have no idea how to handle SyntheticTimeoutException, is there any way to ignore or suppress them? Also, whats the root cause of said exception, and what happens if I ignore or suppress them?

[jodydonetti]

Hi @digital88 , did you see them in the logs or are you getting them thrown up to your own code?

Anyway SyntheticTimeoutExceptions are thrown when you enable hard timeouts and those timeouts actually happen.

Have you enabled the feature maybe?
If so, basically you are saying "during a refresh, if the factory takes more than X time, I prefer to receive an exception instead of waiting too much" because you prefer to be fast and handle the error yourself.

If you enabled soft timeout instead, you will not receive them in your code and just see some warnings in the logs. Soft timeout means "during a refresh, if the factory takes more than X time, I prefer to temporarily reuse a stale (expired) value instead of waiting too much".

Warning levels are also configurable (via FusionCacheOptions), so you can "suppress" them by setting the related log level to trace or similar.

Hope this helps, let me know.

[digital88]

did you see them in the logs or are you getting them thrown up to your own code?

Sentry catches them and reports, so I assume they bubble up to my code. They rarely do tho.

Have you enabled the feature maybe?

Yes, as suggested in StepByStep guide, I did enable them, and also enabled soft timeouts. The guide actually mentions SyntheticTimeoutException but I had no idea what to do to handle them, or if I need to do anything at all. The timeouts doc you linked explains it.

So I guess I remove hard timeout from config entirely, I'm ok with getting stale (expired) cache value.

Thank you for answering, you really helped me to better understand soft/hard timeouts.

[jodydonetti]

Happy to have helped, and you helped me too: now that you mentioned it, I think I'll add a paragraph in the Timeouts docs to explicitly state what happens when enabling hard timeouts, including the exception thrown.
Thanks!