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Posted to user@struts.apache.org by Hubert Rabago <ja...@yahoo.com> on 2004/01/08 16:55:05 UTC
Re: Summary - server hangs after finite number of requests
Wow, I hope most other people conclude with a summary like this after a problem
is resolved. This surely makes it easier for people who do the right thing by
scouring the archives before posting to the mailing list.
--- Heather Marie Buch <hb...@imf.au.dk> wrote:
> I solved the problem, thanks to all the helpful advice I received.
>
> Now I can submit an ActionForm, whether my submission is valid and the
> Action servlet forwards me to the "success" jsp page from my
> action-mapping, or invalid, in which case the Action servlet saves some
> errors into my ActionErrors object and returns me to the "input" page from
> my action-mapping, without the server hanging.
>
> In other words, I can log in correctly, press the back button, and log in
> correctly more than 9 times. I can also log in incorrectly and try again
> more than 9 times. I can do it 20 times! 8 million! (but then I would
> miss Christmas)
>
> Anyway, here is what I have learned from all this:
>
> 1. be sure to close the database connection (Anthony Martin, Geeta Ramani)
>
> 2. limit the connection pool to a single connection during development
> (Andrew Hill)
>
> 3. "You defintely do not want to hang on to a connection longer than
> absolutely necessary. So if you get a connection from your pool at say
> the start of a database access method, make sure you release it back to
> the pool at the end of that method. Plus make sure you place this code in
> a **finally* block - so regardless of whether or not your database query
> was a success, the connection is released to the pool.." (Geeta Ramani)
>
> 4. There is good documentation on using dbcp with tomcat at:
>
>
http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html
>
> and at:
>
> http://jakarta.apache.org/commons/dbcp/configuration.html
> (Manfred Wolff)
>
> Thanks very much to everyone who helped. This has been a good learning
> experience!
>
> Heather Buch
>
>
> On Wed, 7 Jan 2004, Geeta Ramani wrote:
>
> > Heather:
> >
> > Sounds like you nailed down your problem. You defintely do not want to hang
> on to a
> > connection longer than absolutely necessary. So if you get a connection from
> your
> > pool at say the start of a database access method, make sure you release it
> back to
> > the pool at the end of that method. Plus make sure you place this code in a
> > **finally* block - so regardless of whether or not your database query was a
> success,
> > the connection is released to the pool..
> >
> > Also the earlier suggesstion of having just one connection in the pool during
> > development works perfectly - we have used it for a while now and have been
> able to
> > uncover errors we otherwise would not have..
> >
> > Good luck!
> > Geeta
> >
> > Heather Marie Buch wrote:
> >
> > > Hi,
> > >
> > > PROBLEM SOLVED (sort of)
> > >
> > > It was because I failed to close the database connections. Well, I closed
> > > them too late.
> > >
> > > I had things set up so that when a user logs on, a "service" object is
> > > created for them. The Action servlet calls the service and receive
> > > business objects. The service talks to the database and creates
> > > business objects to give back to the action servlets. I had been
> > > fetching a new connection from the pool upon initialization of the
> > > service, and returning the connection to the pool when the
> > > user logged out and the service object was destroyed.
> > >
> > > When I change my code so that the "service" creates a new db
> > > connection each time it interacts with the db, and returns the connection
> > > in the same method, the server no longer hangs. So I guess I will have to
> > > change it to "one connection per query" instead of "one connection per
> > > user".
> > >
> > > Does this sound right?
> > >
> > > Thanks all!
> > >
> > > Heather Buch
> > >
> > > On Tue, 6 Jan 2004, Anthony Martin wrote:
> > >
> > > > I've had something like that happen when I call
> > > > getDataSource(request).getConnection() and forget to close them. After a
> > > > finite number of requests, the server appears to hang. Actually,
> depending
> > > > on the settings, it will timeout. But how you handle the exception could
> > > > prevent it from being properly reported.
> > > >
> > > >
> > > > On 1/6/04 11:38 AM, in article
> > > > Pine.HPP.3.95.1040106202636.8248L-100000@aragorn.imf.au.dk, "Heather
> Marie
> > > > Buch" <hb...@imf.au.dk> wrote:
> > > >
> > > > >
> > > > > Manfred Wolff wrote:
> > > > >
> > > > >> Heather.
> > > > >>
> > > > >> Have you studied the tomcat logs?
> > > > >
> > > > > Yes, I have. This is the only thing that is remotely interesting.
> > > > > In localhost_log.2004-01-06.txt I get this:
> > > > >
> > > > > 2004-01-06 03:38:41 action: null
> > > > > 2004-01-06 03:40:08 action: null
> > > > > 2004-01-06 03:40:12 action: null
> > > > > 2004-01-06 03:40:14 action: null
> > > > > 2004-01-06 03:40:16 action: null
> > > > > 2004-01-06 03:40:18 action: null
> > > > > 2004-01-06 03:40:21 action: null
> > > > > 2004-01-06 03:40:23 action: null
> > > > >
> > > > > (corresponding to the 8 times I try to log in). I don't really know
> where it
> > > > > is
> > > > > coming from. I would like to know what is generating the above, so I
> could to
> > > > > in and modify the logging
> > > > > statements to produce a bit more detail!
> > > > >
> > > > > I also have log4j statements in my own code and have been testing this.
> But I
> > > > > can't generate any error or anything beyond the normal output, 8 times.
> > > > >
> > > > > What is interesting is that it always fails on the 9th try. I don't
> think it
> > > > > is
> > > > > a matter of seconds either. I have tested over a longer period (10
> minutes),
> > > > > but
> > > > > it still gives me 8 requests before it hangs.
> > > > >
> > > > > And Geeta Ramani - thanks. I will take another look at the jdbc stuff!
> > > > >
> > > > > Best,
> > > > >
> > > > > Heather Buch
> > > > >
> > > > >
> > > > >
> > > > >>
> > > > >> Manfred Wolff
> > > > >>
> > > > >> Heather Marie Buch wrote:
> > > > >>
> > > > >>> Hi all,
> > > > >>>
> > > > >>> If I submit the same page more than 8 times, my server dies and I
> have to
> > > > >>> restart. For example, the first 8 times I enter the wrong password,
> struts
> > > > >>> will simply return me to my original form with an error message.
> However,
> > > > >>> the 9th time - the server hangs.
> > > > >>>
> > > > >>> This also occurs if I enter the correct password, then press the
> > > > >>> "back" button and return to the original login screen and submit
> again. I
> > > > >>> can only repeat this 8 times. The server hangs on the 9th try.
> > > > >>>
> > > > >>> I am using:
> > > > >>>
> > > > >>> tomcat 4.1.12
> > > > >>> httpd 2.0.43
> > > > >>> mysql 3.23.53
> > > > >>> struts 1.1
> > > > >>>
> > > > >>> I am not even sure if this is a struts problem. I suspect it is
> because I
> > > > >>> tried that back button trick with a plain old servlet, and I was
> able to
> > > > >>> do it more than 9 times.
> > > > >>>
> > > > >>> Any help would be greatly appreciated! My boss wants users to be able
> to
> > > > >>> try passwords more than 9 times!
> > > > >>>
> > > > >>> Thanks,
> > > > >>>
> > > > >>> Heather Buch
> > > >
> > > >
> > > >
> > > > ---------------------------------------------------------------------
> > > > To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
>
=== message truncated ===
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Re: Summary - server hangs after finite number of requests
Posted by Heather Marie Buch <hb...@imf.au.dk>.
That was to ease my guilt complex about always asking for help, but never
answering help questions...I figure if I can't answer questions, at least
I can write a summary of the answers I got! (when I have time).
Heather
On Thu, 8 Jan 2004, Hubert Rabago wrote:
> Wow, I hope most other people conclude with a summary like this after a problem
> is resolved. This surely makes it easier for people who do the right thing by
> scouring the archives before posting to the mailing list.
>
> --- Heather Marie Buch <hb...@imf.au.dk> wrote:
> > I solved the problem, thanks to all the helpful advice I received.
> >
> > Now I can submit an ActionForm, whether my submission is valid and the
> > Action servlet forwards me to the "success" jsp page from my
> > action-mapping, or invalid, in which case the Action servlet saves some
> > errors into my ActionErrors object and returns me to the "input" page from
> > my action-mapping, without the server hanging.
> >
> > In other words, I can log in correctly, press the back button, and log in
> > correctly more than 9 times. I can also log in incorrectly and try again
> > more than 9 times. I can do it 20 times! 8 million! (but then I would
> > miss Christmas)
> >
> > Anyway, here is what I have learned from all this:
> >
> > 1. be sure to close the database connection (Anthony Martin, Geeta Ramani)
> >
> > 2. limit the connection pool to a single connection during development
> > (Andrew Hill)
> >
> > 3. "You defintely do not want to hang on to a connection longer than
> > absolutely necessary. So if you get a connection from your pool at say
> > the start of a database access method, make sure you release it back to
> > the pool at the end of that method. Plus make sure you place this code in
> > a **finally* block - so regardless of whether or not your database query
> > was a success, the connection is released to the pool.." (Geeta Ramani)
> >
> > 4. There is good documentation on using dbcp with tomcat at:
> >
> >
> http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html
> >
> > and at:
> >
> > http://jakarta.apache.org/commons/dbcp/configuration.html
> > (Manfred Wolff)
> >
> > Thanks very much to everyone who helped. This has been a good learning
> > experience!
> >
> > Heather Buch
> >
> >
> > On Wed, 7 Jan 2004, Geeta Ramani wrote:
> >
> > > Heather:
> > >
> > > Sounds like you nailed down your problem. You defintely do not want to hang
> > on to a
> > > connection longer than absolutely necessary. So if you get a connection from
> > your
> > > pool at say the start of a database access method, make sure you release it
> > back to
> > > the pool at the end of that method. Plus make sure you place this code in a
> > > **finally* block - so regardless of whether or not your database query was a
> > success,
> > > the connection is released to the pool..
> > >
> > > Also the earlier suggesstion of having just one connection in the pool during
> > > development works perfectly - we have used it for a while now and have been
> > able to
> > > uncover errors we otherwise would not have..
> > >
> > > Good luck!
> > > Geeta
> > >
> > > Heather Marie Buch wrote:
> > >
> > > > Hi,
> > > >
> > > > PROBLEM SOLVED (sort of)
> > > >
> > > > It was because I failed to close the database connections. Well, I closed
> > > > them too late.
> > > >
> > > > I had things set up so that when a user logs on, a "service" object is
> > > > created for them. The Action servlet calls the service and receive
> > > > business objects. The service talks to the database and creates
> > > > business objects to give back to the action servlets. I had been
> > > > fetching a new connection from the pool upon initialization of the
> > > > service, and returning the connection to the pool when the
> > > > user logged out and the service object was destroyed.
> > > >
> > > > When I change my code so that the "service" creates a new db
> > > > connection each time it interacts with the db, and returns the connection
> > > > in the same method, the server no longer hangs. So I guess I will have to
> > > > change it to "one connection per query" instead of "one connection per
> > > > user".
> > > >
> > > > Does this sound right?
> > > >
> > > > Thanks all!
> > > >
> > > > Heather Buch
> > > >
> > > > On Tue, 6 Jan 2004, Anthony Martin wrote:
> > > >
> > > > > I've had something like that happen when I call
> > > > > getDataSource(request).getConnection() and forget to close them. After a
> > > > > finite number of requests, the server appears to hang. Actually,
> > depending
> > > > > on the settings, it will timeout. But how you handle the exception could
> > > > > prevent it from being properly reported.
> > > > >
> > > > >
> > > > > On 1/6/04 11:38 AM, in article
> > > > > Pine.HPP.3.95.1040106202636.8248L-100000@aragorn.imf.au.dk, "Heather
> > Marie
> > > > > Buch" <hb...@imf.au.dk> wrote:
> > > > >
> > > > > >
> > > > > > Manfred Wolff wrote:
> > > > > >
> > > > > >> Heather.
> > > > > >>
> > > > > >> Have you studied the tomcat logs?
> > > > > >
> > > > > > Yes, I have. This is the only thing that is remotely interesting.
> > > > > > In localhost_log.2004-01-06.txt I get this:
> > > > > >
> > > > > > 2004-01-06 03:38:41 action: null
> > > > > > 2004-01-06 03:40:08 action: null
> > > > > > 2004-01-06 03:40:12 action: null
> > > > > > 2004-01-06 03:40:14 action: null
> > > > > > 2004-01-06 03:40:16 action: null
> > > > > > 2004-01-06 03:40:18 action: null
> > > > > > 2004-01-06 03:40:21 action: null
> > > > > > 2004-01-06 03:40:23 action: null
> > > > > >
> > > > > > (corresponding to the 8 times I try to log in). I don't really know
> > where it
> > > > > > is
> > > > > > coming from. I would like to know what is generating the above, so I
> > could to
> > > > > > in and modify the logging
> > > > > > statements to produce a bit more detail!
> > > > > >
> > > > > > I also have log4j statements in my own code and have been testing this.
> > But I
> > > > > > can't generate any error or anything beyond the normal output, 8 times.
> > > > > >
> > > > > > What is interesting is that it always fails on the 9th try. I don't
> > think it
> > > > > > is
> > > > > > a matter of seconds either. I have tested over a longer period (10
> > minutes),
> > > > > > but
> > > > > > it still gives me 8 requests before it hangs.
> > > > > >
> > > > > > And Geeta Ramani - thanks. I will take another look at the jdbc stuff!
> > > > > >
> > > > > > Best,
> > > > > >
> > > > > > Heather Buch
> > > > > >
> > > > > >
> > > > > >
> > > > > >>
> > > > > >> Manfred Wolff
> > > > > >>
> > > > > >> Heather Marie Buch wrote:
> > > > > >>
> > > > > >>> Hi all,
> > > > > >>>
> > > > > >>> If I submit the same page more than 8 times, my server dies and I
> > have to
> > > > > >>> restart. For example, the first 8 times I enter the wrong password,
> > struts
> > > > > >>> will simply return me to my original form with an error message.
> > However,
> > > > > >>> the 9th time - the server hangs.
> > > > > >>>
> > > > > >>> This also occurs if I enter the correct password, then press the
> > > > > >>> "back" button and return to the original login screen and submit
> > again. I
> > > > > >>> can only repeat this 8 times. The server hangs on the 9th try.
> > > > > >>>
> > > > > >>> I am using:
> > > > > >>>
> > > > > >>> tomcat 4.1.12
> > > > > >>> httpd 2.0.43
> > > > > >>> mysql 3.23.53
> > > > > >>> struts 1.1
> > > > > >>>
> > > > > >>> I am not even sure if this is a struts problem. I suspect it is
> > because I
> > > > > >>> tried that back button trick with a plain old servlet, and I was
> > able to
> > > > > >>> do it more than 9 times.
> > > > > >>>
> > > > > >>> Any help would be greatly appreciated! My boss wants users to be able
> > to
> > > > > >>> try passwords more than 9 times!
> > > > > >>>
> > > > > >>> Thanks,
> > > > > >>>
> > > > > >>> Heather Buch
> > > > >
> > > > >
> > > > >
> > > > > ---------------------------------------------------------------------
> > > > > To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> >
> === message truncated ===
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
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>
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> For additional commands, e-mail: struts-user-help@jakarta.apache.org
>
>
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RE: Summary - server hangs after finite number of requests
Posted by Andrew Hill <an...@gridnode.com>.
+1
Thanks Heather!
-----Original Message-----
From: Hubert Rabago [mailto:jakartauser@yahoo.com]
Sent: Thursday, 8 January 2004 23:55
To: Struts Users Mailing List
Subject: Re: Summary - server hangs after finite number of requests
Wow, I hope most other people conclude with a summary like this after a
problem
is resolved. This surely makes it easier for people who do the right thing
by
scouring the archives before posting to the mailing list.
--- Heather Marie Buch <hb...@imf.au.dk> wrote:
> I solved the problem, thanks to all the helpful advice I received.
>
> Now I can submit an ActionForm, whether my submission is valid and the
> Action servlet forwards me to the "success" jsp page from my
> action-mapping, or invalid, in which case the Action servlet saves some
> errors into my ActionErrors object and returns me to the "input" page from
> my action-mapping, without the server hanging.
>
> In other words, I can log in correctly, press the back button, and log in
> correctly more than 9 times. I can also log in incorrectly and try again
> more than 9 times. I can do it 20 times! 8 million! (but then I would
> miss Christmas)
>
> Anyway, here is what I have learned from all this:
>
> 1. be sure to close the database connection (Anthony Martin, Geeta Ramani)
>
> 2. limit the connection pool to a single connection during development
> (Andrew Hill)
>
> 3. "You defintely do not want to hang on to a connection longer than
> absolutely necessary. So if you get a connection from your pool at say
> the start of a database access method, make sure you release it back to
> the pool at the end of that method. Plus make sure you place this code in
> a **finally* block - so regardless of whether or not your database query
> was a success, the connection is released to the pool.." (Geeta Ramani)
>
> 4. There is good documentation on using dbcp with tomcat at:
>
>
http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-how
to.html
>
> and at:
>
> http://jakarta.apache.org/commons/dbcp/configuration.html
> (Manfred Wolff)
>
> Thanks very much to everyone who helped. This has been a good learning
> experience!
>
> Heather Buch
>
>
> On Wed, 7 Jan 2004, Geeta Ramani wrote:
>
> > Heather:
> >
> > Sounds like you nailed down your problem. You defintely do not want to
hang
> on to a
> > connection longer than absolutely necessary. So if you get a connection
from
> your
> > pool at say the start of a database access method, make sure you release
it
> back to
> > the pool at the end of that method. Plus make sure you place this code
in a
> > **finally* block - so regardless of whether or not your database query
was a
> success,
> > the connection is released to the pool..
> >
> > Also the earlier suggesstion of having just one connection in the pool
during
> > development works perfectly - we have used it for a while now and have
been
> able to
> > uncover errors we otherwise would not have..
> >
> > Good luck!
> > Geeta
> >
> > Heather Marie Buch wrote:
> >
> > > Hi,
> > >
> > > PROBLEM SOLVED (sort of)
> > >
> > > It was because I failed to close the database connections. Well, I
closed
> > > them too late.
> > >
> > > I had things set up so that when a user logs on, a "service" object is
> > > created for them. The Action servlet calls the service and receive
> > > business objects. The service talks to the database and creates
> > > business objects to give back to the action servlets. I had been
> > > fetching a new connection from the pool upon initialization of the
> > > service, and returning the connection to the pool when the
> > > user logged out and the service object was destroyed.
> > >
> > > When I change my code so that the "service" creates a new db
> > > connection each time it interacts with the db, and returns the
connection
> > > in the same method, the server no longer hangs. So I guess I will have
to
> > > change it to "one connection per query" instead of "one connection per
> > > user".
> > >
> > > Does this sound right?
> > >
> > > Thanks all!
> > >
> > > Heather Buch
> > >
> > > On Tue, 6 Jan 2004, Anthony Martin wrote:
> > >
> > > > I've had something like that happen when I call
> > > > getDataSource(request).getConnection() and forget to close them.
After a
> > > > finite number of requests, the server appears to hang. Actually,
> depending
> > > > on the settings, it will timeout. But how you handle the exception
could
> > > > prevent it from being properly reported.
> > > >
> > > >
> > > > On 1/6/04 11:38 AM, in article
> > > > Pine.HPP.3.95.1040106202636.8248L-100000@aragorn.imf.au.dk, "Heather
> Marie
> > > > Buch" <hb...@imf.au.dk> wrote:
> > > >
> > > > >
> > > > > Manfred Wolff wrote:
> > > > >
> > > > >> Heather.
> > > > >>
> > > > >> Have you studied the tomcat logs?
> > > > >
> > > > > Yes, I have. This is the only thing that is remotely interesting.
> > > > > In localhost_log.2004-01-06.txt I get this:
> > > > >
> > > > > 2004-01-06 03:38:41 action: null
> > > > > 2004-01-06 03:40:08 action: null
> > > > > 2004-01-06 03:40:12 action: null
> > > > > 2004-01-06 03:40:14 action: null
> > > > > 2004-01-06 03:40:16 action: null
> > > > > 2004-01-06 03:40:18 action: null
> > > > > 2004-01-06 03:40:21 action: null
> > > > > 2004-01-06 03:40:23 action: null
> > > > >
> > > > > (corresponding to the 8 times I try to log in). I don't really
know
> where it
> > > > > is
> > > > > coming from. I would like to know what is generating the above, so
I
> could to
> > > > > in and modify the logging
> > > > > statements to produce a bit more detail!
> > > > >
> > > > > I also have log4j statements in my own code and have been testing
this.
> But I
> > > > > can't generate any error or anything beyond the normal output, 8
times.
> > > > >
> > > > > What is interesting is that it always fails on the 9th try. I
don't
> think it
> > > > > is
> > > > > a matter of seconds either. I have tested over a longer period (10
> minutes),
> > > > > but
> > > > > it still gives me 8 requests before it hangs.
> > > > >
> > > > > And Geeta Ramani - thanks. I will take another look at the jdbc
stuff!
> > > > >
> > > > > Best,
> > > > >
> > > > > Heather Buch
> > > > >
> > > > >
> > > > >
> > > > >>
> > > > >> Manfred Wolff
> > > > >>
> > > > >> Heather Marie Buch wrote:
> > > > >>
> > > > >>> Hi all,
> > > > >>>
> > > > >>> If I submit the same page more than 8 times, my server dies and
I
> have to
> > > > >>> restart. For example, the first 8 times I enter the wrong
password,
> struts
> > > > >>> will simply return me to my original form with an error message.
> However,
> > > > >>> the 9th time - the server hangs.
> > > > >>>
> > > > >>> This also occurs if I enter the correct password, then press the
> > > > >>> "back" button and return to the original login screen and submit
> again. I
> > > > >>> can only repeat this 8 times. The server hangs on the 9th try.
> > > > >>>
> > > > >>> I am using:
> > > > >>>
> > > > >>> tomcat 4.1.12
> > > > >>> httpd 2.0.43
> > > > >>> mysql 3.23.53
> > > > >>> struts 1.1
> > > > >>>
> > > > >>> I am not even sure if this is a struts problem. I suspect it is
> because I
> > > > >>> tried that back button trick with a plain old servlet, and I
was
> able to
> > > > >>> do it more than 9 times.
> > > > >>>
> > > > >>> Any help would be greatly appreciated! My boss wants users to be
able
> to
> > > > >>> try passwords more than 9 times!
> > > > >>>
> > > > >>> Thanks,
> > > > >>>
> > > > >>> Heather Buch
> > > >
> > > >
> > > >
> > >
> ---------------------------------------------------------------------
> > > > To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
>
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