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From ShawnWalker <...@git.apache.org>
Subject [GitHub] accumulo pull request: ACCUMULO-4229 BatchWriter Locator cache out...
Date Fri, 29 Apr 2016 15:41:26 GMT
Github user ShawnWalker commented on the pull request:

    https://github.com/apache/accumulo/pull/96#issuecomment-215765483
  
    Instead of trying to wrap things up so that these classes can pseudo-safely hold references
to instances of `TabletLocator`, I feel that it would be much simpler to establish the rule
"thou shalt not hold a reference to this for an extended period", and make changes appropriately.
 
    
    By which I mean:
    1. Refactor `ConditionalWriterImpl` to obtain a temporary `TabletLocator` reference at
the beginning of each method that needs it (`queue(...)`, `sendToServer(...)`, `invalidateSession(...)`),
instead of obtaining a single reference in the constructor.
    2. Modify `TimeoutTabletLocator` so that its constructor takes a `ClientContext` and a
tableId, like your current pull request already does.  But have each of it's methods invoke
`TabletLocator.getLocator(...)` anew.
    
    While I'm dubious that it'd be a real concern, if we felt that this would have significant
performance impact (due to lock contention), then it should be possible to partially ameliorate
the hit by using a Guava Cache or even a `ConcurrentHashMap`.


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