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From "Joshua McKenzie (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-6283) Windows 7 data files keept open / can't be deleted after compaction.
Date Thu, 20 Feb 2014 16:19:23 GMT


Joshua McKenzie commented on CASSANDRA-6283:

It's possible the two are the same underlying problem.  We use hardlinks both during the snapshot
process and during flushing of memtables - I'll have to think for a bit on the best way to
test that theory out since your stack shows us the LEAK being cleaned up but doesn't (and
can't) give us any indication of who it is that might still hold the reference to the handle.

As for the tmp folder and file growth - the hard links won't be kept open in the FD table
for java so we shouldn't run the risk of an FD limit, however the drive space would still
be used until the process was shut down.  I was thinking the addition of a periodic "delete
tmp/moved_hard_links/*" type pass should help mitigate that, though it smells hacky to me.

Another option would be copying files instead of hard linking them during these operations
on Windows only, but I think the performance ramifications of that make that option unworkable.

> Windows 7 data files keept open / can't be deleted after compaction.
> --------------------------------------------------------------------
>                 Key: CASSANDRA-6283
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Windows 7 (32) / Java
>            Reporter: Andreas Schnitzerling
>            Assignee: Joshua McKenzie
>              Labels: compaction
>             Fix For: 2.0.6
>         Attachments: leakdetect.patch, screenshot-1.jpg, system.log
> Files cannot be deleted, patch CASSANDRA-5383 (Win7 deleting problem) doesn't help on
Win-7 on Cassandra 2.0.2. Even 2.1 Snapshot is not running. The cause is: Opened file handles
seem to be lost and not closed properly. Win 7 blames, that another process is still using
the file (but its obviously cassandra). Only restart of the server makes the files deleted.
But after heavy using (changes) of tables, there are about 24K files in the data folder (instead
of 35 after every restart) and Cassandra crashes. I experiminted and I found out, that a finalizer
fixes the problem. So after GC the files will be deleted (not optimal, but working fine).
It runs now 2 days continously without problem. Possible fix/test:
> I wrote the following finalizer at the end of class
> {|borderStyle=solid}
> @Override
> protected void finalize() throws Throwable {
> 	deallocate();
> 	super.finalize();
> }
> {code}
> Can somebody test / develop / patch it? Thx.

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