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From "Yonik Seeley" <yo...@apache.org>
Subject Re: help on Lock.obtain(lockWaitTimeout)
Date Thu, 21 Sep 2006 20:05:06 GMT
On 9/21/06, Michael McCandless <lucene@mikemccandless.com> wrote:
> Anyway, my first reaction was to change this to use
> System.currentTimeMillis() to measure elapsed time, but then I
> remembered is a dangerous approach because whenever the clock on the
> machine is updated (eg by a time-sync NTP client) it would mess up
> this function, causing it to either take longer than was asked for (if
> clock is moved backwards) or, to timeout in [much] less time than was
> asked for (if clock was moved forwards).

Um, wow... that's thorough design work!

In this case, I don't think it's something to worry about though.
NTP corrections are likely to be very small, not on the scale of
lock-obtain timeouts.
If one can't obtain a lock, it's due to something else asynchronously
happening, and that throws a lot bigger time variation into the
equation anyway.


-Yonik
http://incubator.apache.org/solr Solr, the open-source Lucene search server

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