RE: [Javaserver-perl] RE: Perl process hangs on new Java(...) call
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RE: [Javaserver-perl] RE: Perl process hangs on new Java(...) call
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From: Jordan R. <jr...@sh...> - 2004-10-29 19:25:37
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I found the problem, and indeed it's not in the JavaServer code!
Using perl alarms helped me to isolate what was hanging. Regarding the
large # of threads, closing the Oracle connection really helped!
=20
I have a quick question regarding JavaServer.
In one of my Java classes being created, I am using an Oracle JDBC
client via a non-static Oracle connection instance variable.
In subsequent class creations of the same class, is the object being
newly instantiated or is there a pooled object being reused?
Additionally, do I need to implement any synchronization methods around
methods that make use of the connection for example?
Thanks very much again. =20
Jordan
-----Original Message-----
From: jav...@li...
[mailto:jav...@li...] On Behalf Of
ma...@zz...
Sent: Thursday, October 14, 2004 10:08 AM
To: Jordan Redner
Cc: jav...@li...
Subject: Re: [Javaserver-perl] RE: Perl process hangs on new Java(...)
call
Wow that's a lotta threads in not so much memory. Yah try to socket
timeout but a more fundamental problem is JavaServer hanging - prolly
running out of memory - look a 'top' next time that happens & see what
the Java process is doing...
M
On Thu, Oct 14, 2004 at 09:48:24AM -0700, Jordan Redner wrote:
> It's hard to reproduce. It seems to happen when the machine is under
> high CPU load. =20
>=20
> The JavaServer typically does have a lot of threads and does run for
> long periods of time. I just checked a production machine and there
are
> 133 threads (ps -ef on Linux) total memory is 151 MB.
>=20
> Thinking about putting a socket timeout in Java.pm... even though it's
> running on localhost, what do you think?
>=20
>=20
>=20
> Jordan
>=20
>=20
> -----Original Message-----
> From: ma...@zz... [mailto:ma...@zz...]=20
> Sent: Thursday, October 14, 2004 8:29 AM
> To: Jordan Redner
> Cc: jav...@li...
> Subject: Re: [Javaserver-perl] RE: Perl process hangs on new Java(...)
> call
>=20
> Can you telnet to 127.0.0.1 port 2000?
> Then try:
>=20
> #!perl
>=20
> use IO::Socket;
> my $socket =3D IO::Socket::INET->new
> (
> PeerAddr =3D> '127.0.0.1',
> PeerPort =3D> 2000,
> );
>=20
> & see if that hangs.
> Does it hang all of the time or only sometimes? Maybe it's the
> JavaServer
> process itself that's hanging. Hm. If only sometimes is it after
> JavaServer
> has been running for a while w/lots of objects?
> I don't think upgrading to 4.7 will help - it's better handling for
Java
> protected fields.
> M
>=20
>=20
> On Thu, Oct 14, 2004 at 08:03:30AM -0700, Jordan Redner wrote:
> > Thanks so much for the fast response.=20
> >=20
> > Server port is always 127.0.0.1
> >=20
> > OS is a couple years old.
> >=20
> > Mandrake: Linux sj7 2.4.19-16mdkenterprise #1 SMP Fri Sep 20
17:34:59
> > CEST 2002 i686=20
> >=20
> > Perl version 5.8.0
> >=20
> >=20
> >=20
> > Do you think upgrading from 4.6 to 4.7 will help? Are there any
> > synchronization issues which were fixed or anything like that? When
I
> > read "better handling of private/protected fields/functions...", I
> > wasn't sure of what this meant internally. JavaServer runs on
several
> > production machines, otherwise I'd just go ahead and try it. =20
> >=20
> > My next step is to install a timeout parm. in the socket constructor
> > inside Java.pm. What are your thoughts on this??
> >=20
> >=20
> > Thanks for your help.
> >=20
> >=20
> >=20
> > Jordan
> >=20
> >=20
> > -----Original Message-----
> > From: ma...@zz... [mailto:ma...@zz...]=20
> > Sent: Wednesday, October 13, 2004 9:33 PM
> > To: Jordan Redner
> > Cc: jav...@li...
> > Subject: Re: Perl process hangs on new Java(...) call
> >=20
> > The only interesting thing the Java.pm constructor does that may
cause
> > it to hang is trying to connect to the remove JavaServer java
process.
> > Try to telnet to port 2000 of your JavaServer machine from the
machine
> > running the perl code to ensure you can make a connection between
the
> > two.
> > Of course you'll want to make sure you're running compatible version
> > of Java.pm & JavaServer (the major version numbers match).
> > Perhaps your DNS is screwey & your JavaServer host is not be
resolved?
> > As to why it stays hung - which operating system are you running on?
> > If perl is 'hung' in a system call (socket connect) perhaps the
> > signal never gets sent.
> > Lemmie know how it goes - we'll get it figured out.
> > Mark
> >=20
> > PS there is a mailing list at sourceforge that you should join (very
> low
> > traffic) for questions such as these:
> > http://lists.sourceforge.net/lists/listinfo/javaserver-perl
> >=20
> >=20
> > On Wed, Oct 13, 2004 at 05:23:47PM -0700, Jordan Redner wrote:
> > > Hi, I hope you can help. I'm using your product as a way to
migrate
> > > some code from Perl to Java so it's a pretty key piece to our
> > strategy.
> > >=20
> > >=20
> > > =20
> > >=20
> > > Even though we put in alarms, we still end up with hung perl
> > processes.
> > > The processes seem to be hung on the line below that is bold, or
> when
> > it
> > > calls out to=20
> > >=20
> > > $java =3D new Java(host =3D> $perlJavaHost,
> > >=20
> > > port =3D> $perlJavaPort,
> > >=20
> > > event_port =3D> -1,
> > >=20
> > > use_tied_arrays =3D> 1
> > >=20
> > > );
> > >=20
> > > =20
> > >=20
> > > Do you have any idea what we can do to solve this problem? Was
this
> a
> > > known problem. The javaServer itself is very stable. This is the
> > only
> > > problem we know about. Is there a way to specify a timeout in the
> > > connection request?
> > >=20
> > > =20
> > >=20
> > > Thanks so much in advance for any help you can provide.
> > >=20
> > > =20
> > >=20
> > > =20
> > >=20
> > > sub getJava {
> > >=20
> > > my ($perlJavaHost,$perlJavaPort,$javaServerRunner,$timeout) =
=3D
> @_;
> > >=20
> > > =20
> > >=20
> > > my $java;
> > >=20
> > > =20
> > >=20
> > > my $retries =3D 0;
> > >=20
> > > =20
> > >=20
> > > while ($retries < 2) {
> > >=20
> > > =20
> > >=20
> > > $retries ++;
> > >=20
> > > =20
> > >=20
> > > ## -- reset the timer for timeout before the eval
block
> > >=20
> > > alarm 0;
> > >=20
> > > =20
> > >=20
> > > eval {=20
> > >=20
> > > local $SIG{ALRM} =3D sub {
> > >=20
> > > ## -- Signal handler to catch the ALRM signal
> > >=20
> > > ## -- log the timeout error and continue next
> > iteration
> > >=20
> > > lib::perl::Infra::Log::Print("-- Timedout on the
> > > JavaServer trying to get a Java object instance --");
> > >=20
> > > next;
> > >=20
> > > };
> > >=20
> > > =20
> > >=20
> > > lib::perl::Infra::Log::Print("-- Setting JavaServer
> alarm
> > > to: $timeout --");
> > >=20
> > > =20
> > >=20
> > > alarm $timeout;
> > >=20
> > > =20
> > >=20
> > > $java =3D new Java(host =3D> $perlJavaHost,
> > >=20
> > > port =3D> $perlJavaPort,
> > >=20
> > > event_port =3D> -1,
> > >=20
> > > use_tied_arrays =3D> 1
> > >=20
> > > );
> > >=20
> > > =20
> > >=20
> > > lib::perl::Infra::Log::Print("-- Successfully obtained
a
> > > Java object --");
> > >=20
> > > =20
> > >=20
> > > ## -- reset the timer for timeout
> > >=20
> > > alarm 0;
> > >=20
> > > };
> > >=20
> > > =20
> > >=20
> > > if (defined $java) {
> > >=20
> > > return $java;
> > >=20
> > > } else {
> > >=20
> > > my $err =3D "";
> > >=20
> > > if ($@) { $err =3D $@; }
> > >=20
> > > =20
> > >=20
> > > if ($main::gLogger){
> > >=20
> > > $err =3D "JavaUtil.pm" . "," . "Failed obtaining Java
> > object,
> > > retry count=3D$retries " . "\n$err";
> > >=20
> > > $main::gLogger->Log("ERROR",$err);
> > >=20
> > > } else {
> > >=20
> > > $err =3D "Failed obtaining Java object, retry
> count=3D$retries
> > "
> > > . "\n$err";
> > >=20
> > > lib::perl::Infra::Log::Print ($err);
> > >=20
> > > }
> > >=20
> > > =20
> > >=20
> > > restartJavaServer($javaServerRunner);
> > >=20
> > > sleep 5;
> > >=20
> > > }
> > >=20
> > > }
> > >=20
> > > =20
> > >=20
> > > return(undef);
> > >=20
> > > =20
> > >=20
> > > }
> > >=20
> > > =20
> > >=20
> > > =20
> > >=20
> > > =20
> > >=20
> > > Jordan
> > >=20
> > > =20
> > >=20
> >=20
> >=20
> >=20
> > -------------------------------------------------------
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> > Jav...@li...
> > https://lists.sourceforge.net/lists/listinfo/javaserver-perl
>=20
-------------------------------------------------------
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