[jboss-jira] [JBoss JIRA] Commented: (JBVFS-159) Native memory leak due to ZipEntryInputStream
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https://jira.jboss.org/browse/JBVFS-159?page=com.atlassian.jira.plugin.sy...
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Marko Strukelj commented on JBVFS-159:
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ZipEntryInputStream (later upgraded to CertificateReaderInputStream which just added extra
functionality for reading certificates) is there to provide reference counting for usages
of underlying ZipFileWrapper.
Without it ZipFileWrapper will increase refCount for every newly read class/resource but
never decrease it. The result is a permanent file handle leak which on windows systems
makes it impossible to delete the file. After enough time the counter would go beyond
MAX_VALUE and into negative territory potentially causing closing of underlying ZipFile
despite outstanding yet unread ZipEntryInputStream - triggering IOException on
class/resource loading. If incrementing of refCount is disabled such an arbitrary closing
will go into effect immediately.
To put it simply - this class plays a role, you may eventually experience problems having
commented it out.
One possible reason for increased memory usage might be the use of finalize(). The
finalize() method is not particularly important - it's just a final safety net for
code that forgets to close unfully read streams - mainly here for possible buggy third
party libraries on which you as a developer may not have much influence. Removing it could
cause existing applications using buggy libraries, and running on Windows to start develop
file locking problems, and this can not be made configurable as a class either has a
finalize() method or doesn't - and that is not configurable ... although there might
be complicated workarounds for that as well ...
Could you repeat your test by removing your initial code comments and by commenting out
just the finalize() method, so that we see if this is the cause?
Native memory leak due to ZipEntryInputStream
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Key: JBVFS-159
URL: https://jira.jboss.org/browse/JBVFS-159
Project: JBoss VFS
Issue Type: Bug
Security Level: Public(Everyone can see)
Affects Versions: 2.1.2.GA
Environment: Redhat (not sure what version) 2.6.9-78.ELsmp
JBoss 5.1.0.GA
JDK 1.6.0_20
JVM parameter:
-XX:+PrintGCTimeStamps -XX:+PrintGCApplicationStoppedTime -verbose:gc
-Dfile.encoding=iso-8859-1 -server -Djava.net.preferIPv4Stack=true
-Doracle.jdbc.V8Compatible=true -Dsun.rmi.dgc.client.gcInterval=3600000
-Dsun.rmi.dgc.server.gcInterval=3600000 -Dnetworkaddress.cache.ttl=300 -Xss128k -Xmn500m
-Dorg.apache.jasper.runtime.BodyContentImpl.LIMIT_BUFFER=true -XX:+PrintGCDetails
-XX:PermSize=256m -XX:MaxPermSize=256m -Xms1500m -Xmx1500m -XX:+HeapDumpOnOutOfMemoryError
-XX:+UseConcMarkSweepGC
Reporter: Samuel Cai
Assignee: Marko Strukelj
We used to use JBoss 4.2.1.GA and JDK 1.6.0_11, and trying JBoss 5.1.0.GA and JDK
1.6.0_20 these days.
I found the process size is more larger than before, 2.5G~2.9G compared to 1.9G.
I was thinking this was a bug of JBoss AS, then filed
https://jira.jboss.org/browse/JBAS-8066
After these days investigation, I think this is a memory leak in VFS, maybe only happen
on our specific environment.
I tried a change on class org.jboss.virtual.plugins.context.zip.ZipFileWrapper, method
openStream:
From:
ZipEntryInputStream zis = new ZipEntryInputStream(this, is);
return zis;
To:
//ZipEntryInputStream zis = new ZipEntryInputStream(this, is);
//return zis;
return is;
That is, don't use ZipEntryInputStream, let any class/method invoking openStream to
close zipFile's inputStream immediatelly.
ZipFile will be in open status, but all steams will be closed well.
This makes the process size down to same as JBoss 4's. I tried going through first 3
pages of site, no problems. May need QA team to test more.
Btw, I tried updating VFS to 2.1.3.SP1/2.2.0.M4/3.0.0.CR5, first two have same size
issue, third one couldn't start.
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