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----- Original Message -----
From: "Peter Bauer" <[EMAIL PROTECTED]>
To: <users@tomcat.apache.org>
Sent: Wednesday, October 17, 2007 5:24 PM
Subject: Re: All threads are currently busy
Good afternoon Martin :-)
On Wednesday 18 October 2000 16:08:34 you wrote:
Good Morning Peter
I assume you have built glibc for debian following the specific build
instructions for debian..following this example
http://www.linux-m32r.org/eng/download.html#debpackage
I did not build the libc packages myself, currently
libc6 2.3.2.ds1-22
libc6-dev 2.3.2.ds1-22
are installed.
This version of TC is quite old ..not sure if its supported anymore
Yes, i know about that. If there is a major bug in this version, i could
argue to upgrade
(at least to the last 4.1.x version) but i would need some facts to be
able to do so.
Can we see the source for the removeActiveRole
I was hoping to see a thread WAIT or something like that... no such luck ;)
I'm wondering if DatabaseAccess is shared and another thread (in another
servlet) wrecks the connection as this uses it.... maybe...
Maybe there is a subtle loop.... through the POST, its waiting for reply,
which is in another thread, which is waiting for this thread...
OK... I'm finished guessing ;)
public static synchronized void removeActiveRoles(final DatabaseAccess
dba, final String terminalid, final String sessionid, boolean isNam) {
//check parameters
if(terminalid == null || terminalid.length() == 0) {
LOG.error("ActiveRoleRemoval.removeActiveRoles(): Could not
remove active roles of terminal, empty terminalid given.");
}
if(sessionid == null || sessionid.length() == 0) {
LOG.error("ActiveRoleRemoval.removeActiveRoles(): Could not
remove active roles of terminal, empty sessionid given.");
}
//get active roles of failed terminal
ThreeValStructure failedRoles = new ThreeValStructure();
String sql = "SELECT name, functionname, role_type FROM
tableactiveuserroles WHERE " +
"terminalid = '" + terminalid + "' AND autologin <>
1";
if (!dba.executeQuery(sql)) {
/* database statement failed */
LOG.error("ActiveRoleRemoval, removeActiveRoles(), sql
statement failed " + sql);
return;
}
while (dba.checkNext()) {
failedRoles.add(dba.getValue("name"),
dba.getValue("functionname"), dba.getValue("role_type"));
}
//send faked logout message via HTTP POST to commDicora servlet for
failed roles
if(!ActiveRoleRemoval.sendLogoutMessages(failedRoles, sessionid)) {
LOG.error("Sending logout messages for failed roles failed,
continuing");
}
//activate failed roles on all terminals which have a role for
which the failed role is the backup role
BackuproleActivator activator = new BackuproleActivator(dba);
for (int index = 0; index < failedRoles.size(); index++) {
String nameFailedRole = failedRoles.getEl1(index);
//get all relevant terminalids
String sqlSelectTerminals = "SELECT terminalid FROM
tableactiveuserroles WHERE " +
"terminalid <> '" + terminalid +
"' AND typeOfTerminal <> " +
ApusConstants.DICORA_M +
"AND backuprolename = '" +
nameFailedRole + "'";
if (!dba.executeQuery(sqlSelectTerminals)) {
LOG.error("ActiveRoleRemoval, removeActiveRoles(), sql
statement failed " + sqlSelectTerminals);
return;
}
LinkedList<String> backupTerminalsIds = new
LinkedList<String>();
while(dba.checkNext()) {
backupTerminalsIds.add(dba.getValue("terminalid"));
}
if(backupTerminalsIds.size() == 0) {
LOG.debug("ActiveRoleRemoval, removeActiveRoles(): " +
"No backup terminals for Role '" +
nameFailedRole + "' found!");
}
for (Iterator iter = backupTerminalsIds.iterator();
iter.hasNext();) {
String backupTerminalId = (String) iter.next();
activator.sendActivationMessage(backupTerminalId,
nameFailedRole,
failedRoles.getEl3(index),
failedRoles.getEl2(index),
isNam);
}
}
}
specifically are there higher priority threads currently executing so
perhaps yield to those threads may apply?
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.html
There are no threads i am creating which have a non-default priority.
thanks,
Peter
HTH/
Martin--
----- Original Message -----
From: "Peter Bauer" <[EMAIL PROTECTED]>
To: <users@tomcat.apache.org>
Sent: Wednesday, October 17, 2007 4:52 AM
Subject: All threads are currently busy
> Hi all,
>
> System:
> Tomcat 4.1.30 on Debian sarge
> java version "1.5.0_11"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_11-b03)
> Java HotSpot(TM) Client VM (build 1.5.0_11-b03, mixed mode, sharing)
>
> in situations with high load, tomcat sometimes stops responding and is
> not
able to recover from that status. In the catalina.out file, i get the
following line:
> SEVERE: All threads (75) are currently busy, waiting. Increase
> maxThreads
(75) or check the servlet status
> i searched some time in various forums and mailing list archives and
> found
the following links:
http://mail-archives.apache.org/mod_mbox/tomcat-users/200408.mbox/%3c2004Au
g [EMAIL PROTECTED]
> http://marc.info/?l=tomcat-user&m=113297294417902&w=2
> http://www.tek-tips.com/viewthread.cfm?qid=862552&page=3
> http://www.mail-archive.com/[EMAIL PROTECTED]/msg127833.html
>
> Basically there seem to be 2 possible reasons for this behaviour
> 1. A bug (?) in Tomcat or the combination of JDK, glibc, whatever,
> which
causes that tomcat does not
> recover from situations with too much requests. I could not find any
information in the release notes
> of the Tomcat 4.1.x versions.
> 2. Some kind of deadlock or resource (database connections)
> availability
problem which
> keeps the request handling threads from returning from the
> doPost/Get
method.
> So i made a Threaddump using jstack (attached file). Most of the
> threads
are in
> - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
> - java.lang.Object.wait() @bci=2, line=474 (Interpreted frame)
> - org.apache.catalina.core.StandardWrapper.allocate() @bci=223,
> line=704
(Interpreted frame)
> but 19 threads are blocked in the bci 0 of the same static synchronized
method called removeActiveRoles
> which is called from the doPost() method.
>
> -
at.sonorys.dmc.utilities.ActiveRoleRemoval.removeActiveRoles(at.sonorys.dmc
. utilities.DatabaseAccess, java.lang.String, java.lang.String, boolean)
@bci=0 (Interpreted frame)
> - at.sonorys.dmc.CommDicora.CommHandleMessageSession.quitSession()
@bci=23 (Interpreted frame)
> -
> at.sonorys.dmc.CommDicora.CommHandleMessageSession.doHandleSessionMsg()
@bci=131 (Interpreted frame)
> - at.sonorys.dmc.CommDicora.CommHandleMessageSession.evalMessage()
> @bci=1
(Interpreted frame)
> -
at.sonorys.dmc.CommDicora.CommDicoraServlet.doHandleMsg(javax.servlet.http.
H ttpServletResponse, javax.servlet.http.HttpServletRequest) @bci=103
(Interpreted frame)
> -
at.sonorys.dmc.CommDicora.CommDicoraServlet.doPost(javax.servlet.http.HttpS
e rvletRequest, javax.servlet.http.HttpServletResponse) @bci=142
(Interpreted frame)
> The servlet implements the SingleThreadModel (not my decision). As you
> can
see from the threaddump, all 19 threads are waiting to
> get into the same static synchronized method. I dont understand this
because there must be one thread IN the method
> which holds the lock of the method? Is it possible for a thread to
> leave
> a
synchronized method without returning the
> lock?
>
> br,
> Peter
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