DiskStore memory leak?

[Martijn Dashorst <ma...@gmail.com>]

In our app that just migrated to wicket 1.3.2 we got a lot of the
following exceptions [0]
and at the same time our app was running low on memory. Now I don't
know which one caused what, but a jmap histogram showed something
rather disturbing:

num   #instances    #bytes  class name
--------------------------------------
  1:     82067   1181214384  [B
  2:   2757758   132372384  java.util.HashMap$Entry
  3:    628473   111755944  [C
  4:    515329    77012440  [Ljava.util.HashMap$Entry;
  5:     28468    44637824  oracle.jdbc.driver.T4CPreparedStatement
  6:    345808    40406568  [I
  7:    576443    32280808  org.apache.wicket.markup.html.basic.Label
  8:    440706    31538440  [Ljava.lang.Object;
  9:    491169    31434816  java.util.HashMap
 10:    144040    25626360  <constMethodKlass>

The number 1 entry is what spooks me. they are 82k byte arrays, taking
a whopping 1.2Gb of memory. A quick calculation shows that this means
14kb per byte[] on average. The only thing that comes to my mind is
that this are serialized pages. Unfortuately I am unable to prove
this, so we have to conduct a thought experiment.

Is it possible that in this case the page's serialization data is not
cleaned up, taking more and more memory?

Martijn

[0] java.lang.RuntimeException: java.io.FileNotFoundException:
/work/vocus/vocus-filestore/3A167A6585AB5D8695AA85D1BBE4D133/pm-null
(No such file or directory)
       at org.apache.wicket.protocol.http.pagestore.FileChannelPool.newFileChannel(FileChannelPool.java:104)
       at org.apache.wicket.protocol.http.pagestore.FileChannelPool.getFileChannel(FileChannelPool.java:171)
       at org.apache.wicket.protocol.http.pagestore.DiskPageStore$SessionEntry.savePage(DiskPageStore.java:241)
       at org.apache.wicket.protocol.http.pagestore.DiskPageStore.flushPagesToSaveList(DiskPageStore.java:889)
       at org.apache.wicket.protocol.http.pagestore.DiskPageStore$PageSavingThread.run(DiskPageStore.java:952)
       at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.FileNotFoundException:
/work/vocus/vocus-filestore/3A167A6585AB5D8695AA85D1BBE4D133/pm-null
(No such file or directory)
       at java.io.RandomAccessFile.open(Native Method)
       at java.io.RandomAccessFile.<init>(RandomAccessFile.java:212)
       at org.apache.wicket.protocol.http.pagestore.FileChannelPool.newFileChannel(FileChannelPool.java:99)
       ... 5 more