HI
Since we now require Java1.5, perhaps we should be using
java.util.concurrent.locks.ReentrantLock(true/*fair*/)
(note the use of the fairness parameter.)
instead of using the synchronized keyword?
I suspect it would reduce the incidence of "Timeout trying to lock
table" when using MVCC mode, because we'd be executing the incoming
queries in the order in which they arrived, instead of in semi-random order.
Personally, I don't use MVCC or MULTI_THREADED, so I'm not inclined to
pursue this, but other people seem to be using those modes, so maybe
they'd like to try?
Regards,
Noel Grandin
Specifically, in the code I talking about here lives in
org.h2.command.Command
public int executeUpdate() {
Object sync = database.isMultiThreaded() ? (Object) session :
(Object) database;
....
synchronized (sync) {
....
}
}
private long filterConcurrentUpdate(DbException e, long start) {
....
database.wait(sleep);
....
}
and in org.h2.table.RegularTable
private void doLock(Session session, int lockMode, boolean exclusive) {
....
database.wait(sleep);
....
}
and in org.h2.mvstore.db.MVTable#doLock(Session session, int lockMode,
boolean exclusive)
and in org.h2.mvstore.db.MVStore.Writer#run()
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