On Nov 21, 2004, at 11:55 PM, Sean Chittenden wrote:
This is similar to sending email in a trigger or on commit where you can't be certain you send email always
and only on a commit.
While this is certainly a possibility, it's definitely closer to the exception and not the normal instance.
While an exception, this is a very real possibility in day to day operations. The absence of any feedback or balancing mechanism between the database and cache makes it impossible to know that they are in sync and even a small error percentage multiplied over time will lead to an ever increasing likelihood of error.
More dangerous is that this discrepancy will NOT always be apparent because without active verification of the correctness of the cache, we will not know about any errors unless the error grows to an obvious point. The errors may cause material damage long before they become obvious. This is a common failure pattern with caches.
Patrick B. Kelly
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