Re: How do I unlock?
What about a shutdown hook?
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() { /* whatever */ }
});
see also http://www.onjava.com/pub/a/onjava/2003/03/26/shutdownhook.html
On Tue, 11 Jan 2005 13:21:42 -0800, Doug Cutting [EMAIL PROTECTED] wrote:
Joseph Ottinger wrote:
As one for whom the question's come up recently, I'd say that locks need
to be terminated gracefully, instead. I've noticed a number of cases where
the locks get abandoned in exceptional conditions, which is almost exactly
what you don't want.
The problem is that this is hard to do from Java. A typical approach is
to put the process id in the lock file, then, if that process is dead,
ignore the lock file. But Java does not let one know process ids. Java
1.4 provides a LockFile mechanism which should mostly solve this, but
Lucene 1.4.3 does not yet require Java 1.4 and hence cannot use that
feature. Lucene 2.0 is likely to require Java 1.4 and should be able to
do a better job of automatically unlocking indexes when processes die.
Doug
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Re: How do I unlock?
I didn't pay full attention to this thread, but it sounds like somebody may be interested in RuntimeShutdownHook (or some similar name) as a place to try to release the locks. Otis --- Joseph Ottinger [EMAIL PROTECTED] wrote: On Tue, 11 Jan 2005, Doug Cutting wrote: Joseph Ottinger wrote: As one for whom the question's come up recently, I'd say that locks need to be terminated gracefully, instead. I've noticed a number of cases where the locks get abandoned in exceptional conditions, which is almost exactly what you don't want. The problem is that this is hard to do from Java. A typical approach is to put the process id in the lock file, then, if that process is dead, ignore the lock file. But Java does not let one know process ids. Java 1.4 provides a LockFile mechanism which should mostly solve this, but Lucene 1.4.3 does not yet require Java 1.4 and hence cannot use that feature. Lucene 2.0 is likely to require Java 1.4 and should be able to do a better job of automatically unlocking indexes when processes die. Agreed - but while there are some situations in which releasing locks is difficult (i.e., JVM catastrophic shutdown), there are others in which attempts could be made via finally blocks, etc. --- Joseph B. Ottinger http://enigmastation.com IT Consultant [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: How do I unlock?
Eh, that exactly :) When I read my emails in reverse order
--- Chris Lamprecht [EMAIL PROTECTED] wrote:
What about a shutdown hook?
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() { /* whatever */ }
});
see also
http://www.onjava.com/pub/a/onjava/2003/03/26/shutdownhook.html
On Tue, 11 Jan 2005 13:21:42 -0800, Doug Cutting [EMAIL PROTECTED]
wrote:
Joseph Ottinger wrote:
As one for whom the question's come up recently, I'd say that
locks need
to be terminated gracefully, instead. I've noticed a number of
cases where
the locks get abandoned in exceptional conditions, which is
almost exactly
what you don't want.
The problem is that this is hard to do from Java. A typical
approach is
to put the process id in the lock file, then, if that process is
dead,
ignore the lock file. But Java does not let one know process ids.
Java
1.4 provides a LockFile mechanism which should mostly solve this,
but
Lucene 1.4.3 does not yet require Java 1.4 and hence cannot use
that
feature. Lucene 2.0 is likely to require Java 1.4 and should be
able to
do a better job of automatically unlocking indexes when processes
die.
Doug
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail:
[EMAIL PROTECTED]
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To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
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To unsubscribe, e-mail: [EMAIL PROTECTED]
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Re: How do I unlock?
: What about a shutdown hook? Interesting idea, at the moment the file is created on disk, the FSDirectory could add a shutdown hook that checked for the existence of the file and if it's still there (implying that the Lock owner failed without releasing the lock) it can forcably remove it. Of course: this assumes that LockFiles are never shared between processes -- ie: if client A is waiting on a lock that client B is holding, does the lock A eventually gets use the same file that B's lock was using, or does the old lock file get deleted and a new one created ? (I don't really understand a lot of Lucene's locking code) -Hoss - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
