On 18-Nov-08, at 8:54 AM, Mark Miller wrote:
Mark Miller wrote:
Toby Cole wrote:
Has anyone else experienced a deadlock when the
DirectUpdateHandler2 does an autocommit?
I'm using a recent snapshot from hudson (apache-
solr-2008-11-12_08-06-21), and quite often when I'm loading data
the server (tomcat 6) gets stuck at line 469 of
DirectUpdateHandler2:
// Check if there is a commit already scheduled for longer
then this time
if( pending != null &&
pending.getDelay(TimeUnit.MILLISECONDS) >= commitMaxTime )
Anyone got any enlightening tips?
There is some inconsistent synchronization I think. Especially
involving pending. Yuck <g>
I would say there are problems with pending, autoCommitCount, and
lastAddedTime. That alone could probably cause a deadlock (who
knows), but it also seems somewhat possible that there is an issue
with the heavy intermingling of locks (there a bunch of locks to be
had in that class). I havn't looked for evidence of that though -
prob makes sense to fix those 3 guys and see if you get reports from
there.
autoCommitCount is written in a CommitTracker.synchronized block
only. It is read to print stats in an unsynchronized fashion, which
perhaps could be fixed, though I can't see how it could cause a problem
lastAddedTime is only written in a call path within a
DirectUpdateHandler2.synchronized block. It is only read in a
CommitTracker.synchronized block. It could read the wrong value, but
I also don't see this causing a problem (a commit might fail to be
scheduled). This could probably also be improved, but doesn't seem
important.
pending seems to be the issue. As long as commit are only triggered
by autocommit, there is no issue as manipulation of pending is always
performed inside CommitTracker.synchronized. But didCommit()/
didRollback() could be called via manual commit, and pending is
directly manipulated during DUH2.close(). I'm having trouble coming
up with a plausible deadlock scenario, but this needs to be fixed. It
isn't as easy as synchronizing didCommit/didRollback, though--this
would introduce definite deadlock scenarios.
Mark, is there any chance you could post the thread dump for the
deadlocked process? Do you issue manual commits during insertion?
-Mike
