Cache Access In Highly Concurrent Systems
Nov 16, 2010
Suppose I have two threads(Thread1, Thread2) where the threads are accessing the cache for a given object such as in the code below nearly at the same time:
Dim expensiveToGetData = Cache("ExpensiveDataKey")
If ExpensiveToGetData is nothing then
'because the cache has expired
ExpensiveToGetData = LoadExpensiveDataFromDataSource()
Cache("ExpensiveDataKey") = ExpensiveToGetData
end If
ProcessExpensiveData(ExpensiveToGetData)
Isn't it possible for both threads to load the cache because they both requested data from the cache that was nothing/expired? I've run some tests on a local machine and it seems that the cache is being loaded more than once. Is this a normal pattern?
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