Knut Anders Hatlen wrote:
Mike Matrigali <[EMAIL PROTECTED]> writes:
Having said that it would be interesting if someone had time to
implement a higher performance latch implementation and plug it in
and see how much it helps. It would decrease the total time spent
in lock manager.
Ok, a new experiment: I removed the calls to LockFactory.latchObject()
and LockFactory.unlatch() in BasePage. Instead, I let BasePage check
manually whether it was latched and use wait/notifyAll if it was. The
patch (which is very simple) is attached.
The original decision to use the lock manager for the latches was to
enable easier debugging of deadlocks during the early development of the
store code. A local latch implementation, like Knut Anders made, does
make a lot of sense, but does leave derby open to undetectable
deadlocks. Given the performance gains it probably is worth the risk,
especially since I don't think we've seen a problem with latch ordering
for many years.
Dan.
