Playback Failures

Even after successful delivery, a message may still fail during playback to the service. Such failures typically abort the playback transaction, which causes the message to return to the service queue. WCF will then detect the message in the queue and retry. If the next call fails too, the message will go back to the queue again, and so on. Continuously retrying this way is often unacceptable. If the initial motivation for the queued service was load leveling, WCF’s auto-retry behavior will generate considerable stress on the service. You need a smart failure-handling schema that deals with the case when the call never succeeds (and, of course, defines “never” in practical terms). The failure handling will determine after how many attempts to give up, after how long to give up, and even the interval at which to try. Different systems need different retry strategies and have different sensitivity to the additional thrashing and probability of success. For example, retrying 10 times with a single retry once every hour is not the same strategy as retrying 10 times at 1-minute intervals, or the same as retrying 5 times, with each attempt consisting of a batch of 2 successive retries separated by a day. In general, it is better to hedge your bets on the causes for the failure and the probability of future success by retrying in a series of batches, to deal with sporadic and intermediate infrastructure issues as well as fluctuating application state. A series of batches, ...

Get Programming WCF Services, 3rd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.