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From Jørgen Løland (JIRA) <j...@apache.org>
Subject [jira] Updated: (DERBY-3497) OOME at slave during replication
Date Thu, 06 Mar 2008 12:14:59 GMT

     [ https://issues.apache.org/jira/browse/DERBY-3497?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Jørgen Løland updated DERBY-3497:

    Attachment: derby-3497-1a.diff

It turns out that ObjectOutputStreams / ObjectInputStreams are supposed to keep references
to all sent objects. 

In patch 1a I added objOutputStream.reset in ReplicationMessageTransmit#writeObject before
sending the new object. This removes the old object references both on the transmitter and
the receiver side. I inserted 1,000,000 records with ~220 characters each and profiled the
memory usage on the slave:

Without reset: byte[] took up 380 MB (98.2% of the heap)
With reset: byte[] took up 6MB (54% of the heap)

Seems like the memoryleak has been identified. I'm running tests on the patch now.

> OOME at slave during replication
> --------------------------------
>                 Key: DERBY-3497
>                 URL: https://issues.apache.org/jira/browse/DERBY-3497
>             Project: Derby
>          Issue Type: Bug
>          Components: Replication
>    Affects Versions:
>         Environment: trunk at revision 633807
>            Reporter: Øystein Grøvlen
>            Assignee: Jørgen Løland
>         Attachments: derby-3497-1a.diff, derby-3497-1a.stat
> After deleting and inserting more than 1 million records during replication, I got 
> java.lang.OutOfMemoryError: Java heap space.
> The heap dump shows that almost the entire heap is byte arrays, and it seems most of
them are referred to by ReplicationMessage objects.  An inspection of the heap dump in VisualVM
it seems that it is references rooted in SocketConnection#objInputStream that keeps them from
being garbage collected.

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