Re: weakly referenced paged queries

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Sun Jun 22 2008 - 16:28:56 EDT

  • Next message: Øyvind Harboe: "Re: weakly referenced paged queries"

    On Jun 20, 2008, at 10:41 PM, Øyvind Harboe wrote:

    > - the JavaDoc explained *why* the synchronization is there and what it
    > is supposed to do and how the client is supposed to use it.

     From the class JavaDocs: "A synchronized list that serves as a
    container of DataObjects"... A Collection is either synchronized or
    not. No other explanation is needed.

    Now regarding the synchronization scope, my current POV (that is
    somewhat different from my past opinion) is that the list methods
    should NOT be synchronized by default (i.e. users should create
    synchronized wrappers if they need to). This way IncrementalFaultList
    will be aligned with standard Java collections. One thing that still
    must be synchronized internally is the DB operations to avoid multiple
    concurrent fetches of the same data. This does not require
    synchronization of most normal list access methods. I.e. the scope of
    synchronization should be significantly reduced. (We can do something
    extra fancy with syncing DB ops per page to allow parallel page
    faulting, but that's certainly not a very high priority task).

    Now your mention of performance issues... My guess without looking at
    the code, this is unlikely to happen due to oversynchronization.
    Compared to other things that are going on, synchronization overhead
    should be negligible. Of course running in profiler should answer that
    for sure.

    Finally thanks for opening CAY-1075. One request - could you submit
    any code as patches instead of full files - it will make it much
    easier to analyze the changes.

    Andrus



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