[opencms-dev] Resolution to deadlocks in getting JDBC connections?
James George
james.george at oracle.com
Wed Jan 28 01:27:01 CET 2004
Hi all,
OpenCMS 5.0.0
9iAS/OC4J 9.0.3.1
Oracle RDBMS 8.1.7.4
all on HPUX
I'm assisting in trouble shooting an OpenCMS implementation on an Oracle
9iAS application server and we are seeing deadlocks occurring between
the genericsql thread using java.sql.DriverManager.getDrivers() and
ApplicationServerThread-X using
com.opencms.dbpool.CmsPool.getConnection() (see below for excerpts from
thread traces).
I've searched the mailing list archives and found references to this
issue, but couldn't find any reference to a fix or suitable workaround.
Do any exist? I checked the history for 5.0.1, but there was no
reference to this issue.
At the moment this is causing intermittent failures in a production
system, so if there are any pointers or suggestions (other than a
nightly restart) anyone can make to help us mitigate this issue, it
would be greatly appreciated.
Thanks in advance!
James
Deadlocked threads:
Found one Java-level deadlock:
=============================
"ApplicationServerThread-25":
waiting to lock monitor 0x18a73c (object 0x4f314438, a java.util.Stack),
which is held by "genericsql"
"genericsql":
waiting to lock monitor 0x18a7b0 (object 0x49e07240, a java.lang.Class),
which is held by "ApplicationServerThread-25"
Java stack information for the threads listed above:
===================================================
"ApplicationServerThread-25":
at com.opencms.dbpool.CmsPool.getConnection(CmsPool.java:217)
- waiting to lock <0x4f314438> (a java.util.Stack)
at com.opencms.dbpool.CmsPool.connect(CmsPool.java:206)
at com.opencms.dbpool.CmsDriver.connect(CmsDriver.java:107)
at java.sql.DriverManager.getConnection(DriverManager.java:512)
- locked <0x49e07240> (a java.lang.Class)
at java.sql.DriverManager.getConnection(DriverManager.java:193)
- locked <0x49e07240> (a java.lang.Class)
at
com.opencms.file.genericSql.CmsDbAccess.readUser(CmsDbAccess.java:10136)
at
com.opencms.file.genericSql.CmsResourceBroker.readUser(CmsResourceBroker.java:6478)
at com.opencms.file.CmsRequestContext.init(CmsRequestContext.java:172)
at com.opencms.file.CmsObject.init(CmsObject.java:2200)
at com.opencms.core.OpenCms.initUser(OpenCms.java:896)
at
com.opencms.core.OpenCmsHttpServlet.initUser(OpenCmsHttpServlet.java:473)
at
com.opencms.core.OpenCmsHttpServlet.doGet(OpenCmsHttpServlet.java:304)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
com.evermind.server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:65)
at oracle.security.jazn.oc4j.JAZNFilter.doFilter(JAZNFilter.java:283)
at
com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:566)
at
com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:306)
at
com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:767)
at
com.evermind.server.http.AJPRequestHandler.run(AJPRequestHandler.java:166)
at
com.evermind.server.http.AJPRequestHandler.run(AJPRequestHandler.java:72)
at
EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:803)
at java.lang.Thread.run(Thread.java:536)
"genericsql":
at java.sql.DriverManager.getDrivers(DriverManager.java:321)
- waiting to lock <0x49e07240> (a java.lang.Class)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:317)
at com.opencms.dbpool.CmsPool.createConnection(CmsPool.java:338)
at com.opencms.dbpool.CmsPool.createConnections(CmsPool.java:320)
at com.opencms.dbpool.CmsPool.run(CmsPool.java:188)
- locked <0x4f314438> (a java.util.Stack)
Found 1 deadlock.
--
-----------------------------------------------
James George - Consultant
Oracle Corporation Ph: +61 8 94267200
Perth, Western Australia Fax: +61 8 93215175
"I like nonsense; it wakes up the brain cells."
- Dr. Seuss
-----------------------------------------------
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