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Posted to dev@tomcat.apache.org by bu...@apache.org on 2015/01/21 09:56:05 UTC
[Bug 57472] New: performance (classloader?) problems with signed
jars in WEB-INF/lib
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
Bug ID: 57472
Summary: performance (classloader?) problems with signed jars
in WEB-INF/lib
Product: Tomcat 8
Version: 8.0.17
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P2
Component: Catalina
Assignee: dev@tomcat.apache.org
Reporter: ole.schulz-hildebrandt@ppimedia.de
cf.
http://mail-archives.apache.org/mod_mbox/tomcat-users/201501.mbox/%3CADA7A9443C47CC4E9C065E9C84C6891D6B3994A3B7%40ex01.ppinet.de%3E
After moving one of our web applications from Tomcat 7 to Tomcat 8 (8.0.17,
Java 1.8.0_25, CentOS 6) the time for deploying and initializing the webapp
increased by a factor of 30 (6s vs. 180s). Analyzing the problem we found out
that it had to do with a signed jar in the WEB-INF/lib of the webapp. It is a
8mb self-signed jar of the jython-library from which many classes are used in
the initializing process of our webapp. When using a non-signed version of the
jar the time for deploying and initializing is the same in Tomcat 8 as in
Tomcat 7.
Profiling and debugging the webapp it turned out that loading a class (and its
depending classes) from the signed jar took extremely long with Tomcat 8 in
comparison to Tomcat 7.
The following is just a hypothesis of a "Tomcat source newbie": Could it be
that (at least some parts of) the verification process for the whole signed jar
is done again and again each time a class from a signed jar is loaded? Looking
at org.apache.catalina.webresources.JarResource:47
(http://svn.apache.org/repos/asf/tomcat/tc8.0.x/trunk/java/org/apache/catalina/webresources/JarResource.java)
a new instance of java.util.jar.JarFile is created each time a single
class-file is read from the jar. Thus the following call of
jarFile.getInputStream(jarEntry) in JarResource:50 causes a call of
JarFile.initializeVerifier() (cf. JarFile:442ff in
http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/8-b132/java/util/jar/JarFile.java).
JarFile.initializeVerifier() seems to do some precalculations (hashing?) for
all files listed in the manifest of the signed jar (cf. JarFile:365ff). Thus
each time a single class is loaded from a signed jar precalculations for all
class files in the signed jar seem to be done. Could this be the reason for our
performance problems (especially in connection with a 8mb signed jar ;-))?
If neccessary I can provide the mentioned 8mb self-signed jar of the
jython-library and/or create a simple sample web application that demonstrates
the issue.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #7 from Andrei Costescu <co...@skymail.ro> ---
Thank you! :)
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #2 from ole.schulz-hildebrandt@ppimedia.de ---
I put an example application signedjar.war here:
https://drive.google.com/file/d/0By0Iea2JkjtKdlI2SGFSaVg2ZWs/view?pli=1
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #4 from Christopher Schultz <ch...@christopherschultz.net> ---
Maybe a ThreadLocal list of JARs to close?
Presumably, the ClassLoader is going to load a whole bunch of classes from
these JAR files at once; probably the first time some feature/group of classes
is used. When a request is completed, maybe we could tell the WebappClassLoader
that the request is done and it can close any JAR files it opened during that
request, rather than having it re-open the JAR each time it loads a class.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #3 from Mark Thomas <ma...@apache.org> ---
I can confirm that it is JAR verification that is causing the slow down. The
way to avoid that is to keep the JAR open for the life of the web application.
However, that causes a catch-22 problem. Keeping the files open will prevent
the web application from being deleted. If the web application can't be deleted
folks that undeploy that way won;t be able to so the web application can't be
stopped (which would be the trigger to close the file).
I need to think about the best way to fix this.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #1 from Mark Thomas <ma...@apache.org> ---
8MB+ will be too big for a Bugzilla attachment but if you can put the file
somewhere I can download it, a web application that reproduces this issue would
be much appreciated.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #8 from ole.schulz-hildebrandt@ppimedia.de ---
thanks for the fast fix of this issue :-)
Startup with tomcat 8.0.x trunk is as fast as tomcat 7 now.
Do I have to close this bug or is that done by you?
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #5 from Mark Thomas <ma...@apache.org> ---
That is sort of what Tomcat 7 does. I think I can port the openJars / closeJars
from Tomcat 7's WebappClassLoader to Tomcat 8's resources implementation.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
--- Comment #6 from Mark Thomas <ma...@apache.org> ---
This has been fixed in trunk and 8.0.x and will be included in 8.0.19 onwards.
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[Bug 57472] performance (classloader?) problems with signed jars in
WEB-INF/lib
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=57472
Mark Thomas <ma...@apache.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
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