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Posted to users@tomcat.apache.org by Taral Shah <ta...@contechsoftware.com> on 2002/08/16 11:40:06 UTC
Persistent Connection
I am using tomcat 3.3
Now I am calling one jsp which loads an applet, internally that applet uses
url connection to fetch data.
Now problem is that when i check with netstat application(its inbuilt in win
nt, run through netstat -n)
I came to know tomcat opens no of connections and keep them in TIME_WAIT
mode.
This is happening with simple jsps as well as with servlet. For each request
it opens around 2/3(depending on the no of jsps included) connection with
<host-ip>:8080 port. These all are of tcp type connections.
I read in some of materials that in Http 1.1, as persistent connection is
used so it keeps the connection open unless I specify them to close.
I wrote in my code as response.setHeader("Connection", "close");
but still the no of open connection increases. In my application if hits are
many then it reaches to thousands.
Has any one seen this before(I think this is for all tomcat-You can check
with netstat).
Has any one explicitly closed the connection through header or is there any
way to specify in tocat configuration so it does not keep the connection
open.
Thanks
Taral Shah
Experience is what you get when you were expecting something else.
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Re: Persistent Connection
Posted by Taral Shah <ta...@contechsoftware.com>.
Thanks A lot Andrew and Mike for providing useful information.
But Just for my knowledge I would like to know, What IIS or Apache doing
specially so the connection closes with them and not with Tomcat.
Any special protocols they are following or what?
I have to compulsory use only tomcat and not apache. And mine is a
networking application so these sockets are concerend for client.
IS there any solution for it, when using only with tomcat or I have to
accept this as a fact and work with it.
Thanks Again.
Taral Shah
Experience is what you get when you were expecting something else.
----- Original Message -----
From: "Andrew Conrad" <an...@attbi.com>
To: "'Tomcat Users List'" <to...@jakarta.apache.org>; "'Taral Shah'"
<ta...@contechsoftware.com>
Sent: Saturday, August 17, 2002 11:42 PM
Subject: RE: Persistent Connection
It's a operating system issue.
<quote>
NOTE: It is normal to have a socket in the TIME_WAIT state for a long
period of time. The time is specified in RFC793 as twice the Maximum
Segment Lifetime (MSL). MSL is specified to be 2 minutes. So, a socket
could be in a TIME_WAIT state for as long as 4 minutes. Some systems
implement different values (less than 2 minutes) for the MSL.
</quote>
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q137984
But if you really want to change the TIME_WAIT, look here
http://support.microsoft.com/default.aspx?scid=kb;en-us;q314053
To test your MSL (maximum segment lifetime), you can use this tool
http://polygraph.ircache.net/doc/msl_test.html
- Andrew
> -----Original Message-----
> From: Taral Shah [mailto:tarals@contechsoftware.com]
> Sent: Saturday, August 17, 2002 2:16 AM
> To: Tomcat Users List
> Subject: Re: Persistent Connection
>
>
> Hi,
> Thanks for reply,
>
> But I am only using tomcat. I dont want to use apache just
> for this reason.Can any one guide me what should i do to
> close this connection in tomcat or to ask tcp/ip stack to
> close connection. Its not at all affecting the performance of
> application but when i see at netstat statstics it sometimes
> shows me thousands of connections open.
>
> Any idea?
> Thanks
> Taral Shah
>
> Experience is what you get when you were expecting something else.
>
> ----- Original Message -----
> From: "Mike Jackson" <mj...@cdi-hq.com>
> To: "Tomcat Users List" <to...@jakarta.apache.org>;
> "Taral Shah" <ta...@contechsoftware.com>
> Sent: Friday, August 16, 2002 10:53 PM
> Subject: RE: Persistent Connection
>
>
> "TIME_WAIT" is something the tcp/ip stack does; it doesn't
> have anything to do with Tomcat per say. What happens (as I
> understand it) is that once your app has closed the
> connection (page is done or whatever), the stack will hold
> the connection in a "TIME_WAIT" state to prevent the other
> end, the client, from reconnecting to the same port.
>
> So the problem isn't really tomcat, its the TCP/IP stack.
> However I've also found that under unix if you're using
> apache+tomcat you don't have a ton of TIME_WAIT sockets on
> the webserver. Apache apparently sets a parameter to
> eliminate the TIME_WAIT sockets, either on close or on open
> of the socket (I don't know which). So what you might want
> to do is run IIS or Apache in front of tomcat. I don't know
> that IIS does the same thing as Apache in regards to the
> sockets, but if it does then it'll work nearly as well in
> front of tomcat. But there is a slight problem here as well,
> you need to be sure that you're using APJ13 not APJ12 as
> APJ12 will open a new connection for each web access that
> tomcat handles. And in that casey you'd get more TIME_WAIT
> sockets. APJ13 multiplexes the requests over one persistent
> socket, so you don't have the extra overhead of opening the
> socket on each request, or the TIME_WAIT socket lingering
> there for some time period.
>
> Also, just as a FYI, under unix you can change the TIME_WAIT
> time period but it's not recommended that you do so. The
> default time period is about 4 minutes as I recall. You can
> probably also change it under windows, but I wouldn't have a
> clue how to do that.
>
> --mikej
> -=-----
> mike jackson
> mjackson@cdi-hq.com
>
> > -----Original Message-----
> > From: Taral Shah [mailto:tarals@contechsoftware.com]
> > Sent: Friday, August 16, 2002 2:40 AM
> > To: Tomcat Users List
> > Subject: Persistent Connection
> >
> >
> > I am using tomcat 3.3
> >
> > Now I am calling one jsp which loads an applet, internally
> that applet
> > uses url connection to fetch data.
> > Now problem is that when i check with netstat application(its
> > inbuilt in win
> > nt, run through netstat -n)
> > I came to know tomcat opens no of connections and keep them
> in TIME_WAIT
> > mode.
> >
> > This is happening with simple jsps as well as with servlet.
> For each
> > request it opens around 2/3(depending on the no of jsps included)
> > connection with <host-ip>:8080 port. These all are of tcp type
> > connections. I read in some of materials that in Http 1.1, as
> > persistent connection is used so it keeps the connection
> open unless I
> > specify them to close.
> >
> > I wrote in my code as response.setHeader("Connection",
> "close"); but
> > still the no of open connection increases. In my
> application if hits
> > are many then it reaches to thousands.
> >
> > Has any one seen this before(I think this is for all tomcat-You can
> > check with netstat). Has any one explicitly closed the connection
> > through header or is there any
> > way to specify in tocat configuration so it does not keep
> the connection
> > open.
> >
> > Thanks
> >
> > Taral Shah
> > Experience is what you get when you were expecting something else.
> >
> >
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
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RE: Persistent Connection
Posted by Andrew Conrad <an...@attbi.com>.
It's a operating system issue.
<quote>
NOTE: It is normal to have a socket in the TIME_WAIT state for a long
period of time. The time is specified in RFC793 as twice the Maximum
Segment Lifetime (MSL). MSL is specified to be 2 minutes. So, a socket
could be in a TIME_WAIT state for as long as 4 minutes. Some systems
implement different values (less than 2 minutes) for the MSL.
</quote>
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q137984
But if you really want to change the TIME_WAIT, look here
http://support.microsoft.com/default.aspx?scid=kb;en-us;q314053
To test your MSL (maximum segment lifetime), you can use this tool
http://polygraph.ircache.net/doc/msl_test.html
- Andrew
> -----Original Message-----
> From: Taral Shah [mailto:tarals@contechsoftware.com]
> Sent: Saturday, August 17, 2002 2:16 AM
> To: Tomcat Users List
> Subject: Re: Persistent Connection
>
>
> Hi,
> Thanks for reply,
>
> But I am only using tomcat. I dont want to use apache just
> for this reason.Can any one guide me what should i do to
> close this connection in tomcat or to ask tcp/ip stack to
> close connection. Its not at all affecting the performance of
> application but when i see at netstat statstics it sometimes
> shows me thousands of connections open.
>
> Any idea?
> Thanks
> Taral Shah
>
> Experience is what you get when you were expecting something else.
>
> ----- Original Message -----
> From: "Mike Jackson" <mj...@cdi-hq.com>
> To: "Tomcat Users List" <to...@jakarta.apache.org>;
> "Taral Shah" <ta...@contechsoftware.com>
> Sent: Friday, August 16, 2002 10:53 PM
> Subject: RE: Persistent Connection
>
>
> "TIME_WAIT" is something the tcp/ip stack does; it doesn't
> have anything to do with Tomcat per say. What happens (as I
> understand it) is that once your app has closed the
> connection (page is done or whatever), the stack will hold
> the connection in a "TIME_WAIT" state to prevent the other
> end, the client, from reconnecting to the same port.
>
> So the problem isn't really tomcat, its the TCP/IP stack.
> However I've also found that under unix if you're using
> apache+tomcat you don't have a ton of TIME_WAIT sockets on
> the webserver. Apache apparently sets a parameter to
> eliminate the TIME_WAIT sockets, either on close or on open
> of the socket (I don't know which). So what you might want
> to do is run IIS or Apache in front of tomcat. I don't know
> that IIS does the same thing as Apache in regards to the
> sockets, but if it does then it'll work nearly as well in
> front of tomcat. But there is a slight problem here as well,
> you need to be sure that you're using APJ13 not APJ12 as
> APJ12 will open a new connection for each web access that
> tomcat handles. And in that casey you'd get more TIME_WAIT
> sockets. APJ13 multiplexes the requests over one persistent
> socket, so you don't have the extra overhead of opening the
> socket on each request, or the TIME_WAIT socket lingering
> there for some time period.
>
> Also, just as a FYI, under unix you can change the TIME_WAIT
> time period but it's not recommended that you do so. The
> default time period is about 4 minutes as I recall. You can
> probably also change it under windows, but I wouldn't have a
> clue how to do that.
>
> --mikej
> -=-----
> mike jackson
> mjackson@cdi-hq.com
>
> > -----Original Message-----
> > From: Taral Shah [mailto:tarals@contechsoftware.com]
> > Sent: Friday, August 16, 2002 2:40 AM
> > To: Tomcat Users List
> > Subject: Persistent Connection
> >
> >
> > I am using tomcat 3.3
> >
> > Now I am calling one jsp which loads an applet, internally
> that applet
> > uses url connection to fetch data.
> > Now problem is that when i check with netstat application(its
> > inbuilt in win
> > nt, run through netstat -n)
> > I came to know tomcat opens no of connections and keep them
> in TIME_WAIT
> > mode.
> >
> > This is happening with simple jsps as well as with servlet.
> For each
> > request it opens around 2/3(depending on the no of jsps included)
> > connection with <host-ip>:8080 port. These all are of tcp type
> > connections. I read in some of materials that in Http 1.1, as
> > persistent connection is used so it keeps the connection
> open unless I
> > specify them to close.
> >
> > I wrote in my code as response.setHeader("Connection",
> "close"); but
> > still the no of open connection increases. In my
> application if hits
> > are many then it reaches to thousands.
> >
> > Has any one seen this before(I think this is for all tomcat-You can
> > check with netstat). Has any one explicitly closed the connection
> > through header or is there any
> > way to specify in tocat configuration so it does not keep
> the connection
> > open.
> >
> > Thanks
> >
> > Taral Shah
> > Experience is what you get when you were expecting something else.
> >
> >
> > --
> > To unsubscribe, e-mail:
> > <ma...@jakarta.apache.org>
> > For additional commands, e-mail:
> > <ma...@jakarta.apache.org>
> >
> >
>
>
> --
> To unsubscribe, e-mail:
> <mailto:tomcat-user-> unsubscribe@jakarta.apache.org>
> For
> additional commands,
> e-mail: <ma...@jakarta.apache.org>
>
>
>
> --
> To unsubscribe, e-mail:
> <mailto:tomcat-user-> unsubscribe@jakarta.apache.org>
> For
> additional commands,
> e-mail: <ma...@jakarta.apache.org>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: Persistent Connection
Posted by Taral Shah <ta...@contechsoftware.com>.
Hi,
Thanks for reply,
But I am only using tomcat. I dont want to use apache just for this
reason.Can any one guide me what should i do to close this connection in
tomcat or to ask tcp/ip stack to close connection.
Its not at all affecting the performance of application but when i see at
netstat statstics it sometimes shows me thousands of connections open.
Any idea?
Thanks
Taral Shah
Experience is what you get when you were expecting something else.
----- Original Message -----
From: "Mike Jackson" <mj...@cdi-hq.com>
To: "Tomcat Users List" <to...@jakarta.apache.org>; "Taral Shah"
<ta...@contechsoftware.com>
Sent: Friday, August 16, 2002 10:53 PM
Subject: RE: Persistent Connection
"TIME_WAIT" is something the tcp/ip stack does; it doesn't have anything
to do with Tomcat per say. What happens (as I understand it) is that once
your app has closed the connection (page is done or whatever), the stack
will hold the connection in a "TIME_WAIT" state to prevent the other end,
the client, from reconnecting to the same port.
So the problem isn't really tomcat, its the TCP/IP stack. However I've
also found that under unix if you're using apache+tomcat you don't have a
ton of TIME_WAIT sockets on the webserver. Apache apparently sets a
parameter to eliminate the TIME_WAIT sockets, either on close or on open
of the socket (I don't know which). So what you might want to do is run
IIS or Apache in front of tomcat. I don't know that IIS does the same
thing as Apache in regards to the sockets, but if it does then it'll work
nearly as well in front of tomcat. But there is a slight problem here
as well, you need to be sure that you're using APJ13 not APJ12 as APJ12
will open a new connection for each web access that tomcat handles. And
in that casey you'd get more TIME_WAIT sockets. APJ13 multiplexes the
requests over one persistent socket, so you don't have the extra overhead
of opening the socket on each request, or the TIME_WAIT socket lingering
there for some time period.
Also, just as a FYI, under unix you can change the TIME_WAIT time period
but it's not recommended that you do so. The default time period is about
4 minutes as I recall. You can probably also change it under windows, but
I wouldn't have a clue how to do that.
--mikej
-=-----
mike jackson
mjackson@cdi-hq.com
> -----Original Message-----
> From: Taral Shah [mailto:tarals@contechsoftware.com]
> Sent: Friday, August 16, 2002 2:40 AM
> To: Tomcat Users List
> Subject: Persistent Connection
>
>
> I am using tomcat 3.3
>
> Now I am calling one jsp which loads an applet, internally that
> applet uses
> url connection to fetch data.
> Now problem is that when i check with netstat application(its
> inbuilt in win
> nt, run through netstat -n)
> I came to know tomcat opens no of connections and keep them in TIME_WAIT
> mode.
>
> This is happening with simple jsps as well as with servlet. For
> each request
> it opens around 2/3(depending on the no of jsps included) connection with
> <host-ip>:8080 port. These all are of tcp type connections.
> I read in some of materials that in Http 1.1, as persistent connection is
> used so it keeps the connection open unless I specify them to close.
>
> I wrote in my code as response.setHeader("Connection", "close");
> but still the no of open connection increases. In my application
> if hits are
> many then it reaches to thousands.
>
> Has any one seen this before(I think this is for all tomcat-You can check
> with netstat).
> Has any one explicitly closed the connection through header or is
> there any
> way to specify in tocat configuration so it does not keep the connection
> open.
>
> Thanks
>
> Taral Shah
> Experience is what you get when you were expecting something else.
>
>
> --
> To unsubscribe, e-mail:
> <ma...@jakarta.apache.org>
> For additional commands, e-mail:
> <ma...@jakarta.apache.org>
>
>
--
To unsubscribe, e-mail:
<ma...@jakarta.apache.org>
For additional commands, e-mail:
<ma...@jakarta.apache.org>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
RE: Persistent Connection
Posted by Mike Jackson <mj...@cdi-hq.com>.
"TIME_WAIT" is something the tcp/ip stack does; it doesn't have anything
to do with Tomcat per say. What happens (as I understand it) is that once
your app has closed the connection (page is done or whatever), the stack
will hold the connection in a "TIME_WAIT" state to prevent the other end,
the client, from reconnecting to the same port.
So the problem isn't really tomcat, its the TCP/IP stack. However I've
also found that under unix if you're using apache+tomcat you don't have a
ton of TIME_WAIT sockets on the webserver. Apache apparently sets a
parameter to eliminate the TIME_WAIT sockets, either on close or on open
of the socket (I don't know which). So what you might want to do is run
IIS or Apache in front of tomcat. I don't know that IIS does the same
thing as Apache in regards to the sockets, but if it does then it'll work
nearly as well in front of tomcat. But there is a slight problem here
as well, you need to be sure that you're using APJ13 not APJ12 as APJ12
will open a new connection for each web access that tomcat handles. And
in that casey you'd get more TIME_WAIT sockets. APJ13 multiplexes the
requests over one persistent socket, so you don't have the extra overhead
of opening the socket on each request, or the TIME_WAIT socket lingering
there for some time period.
Also, just as a FYI, under unix you can change the TIME_WAIT time period
but it's not recommended that you do so. The default time period is about
4 minutes as I recall. You can probably also change it under windows, but
I wouldn't have a clue how to do that.
--mikej
-=-----
mike jackson
mjackson@cdi-hq.com
> -----Original Message-----
> From: Taral Shah [mailto:tarals@contechsoftware.com]
> Sent: Friday, August 16, 2002 2:40 AM
> To: Tomcat Users List
> Subject: Persistent Connection
>
>
> I am using tomcat 3.3
>
> Now I am calling one jsp which loads an applet, internally that
> applet uses
> url connection to fetch data.
> Now problem is that when i check with netstat application(its
> inbuilt in win
> nt, run through netstat -n)
> I came to know tomcat opens no of connections and keep them in TIME_WAIT
> mode.
>
> This is happening with simple jsps as well as with servlet. For
> each request
> it opens around 2/3(depending on the no of jsps included) connection with
> <host-ip>:8080 port. These all are of tcp type connections.
> I read in some of materials that in Http 1.1, as persistent connection is
> used so it keeps the connection open unless I specify them to close.
>
> I wrote in my code as response.setHeader("Connection", "close");
> but still the no of open connection increases. In my application
> if hits are
> many then it reaches to thousands.
>
> Has any one seen this before(I think this is for all tomcat-You can check
> with netstat).
> Has any one explicitly closed the connection through header or is
> there any
> way to specify in tocat configuration so it does not keep the connection
> open.
>
> Thanks
>
> Taral Shah
> Experience is what you get when you were expecting something else.
>
>
> --
> To unsubscribe, e-mail:
> <ma...@jakarta.apache.org>
> For additional commands, e-mail:
> <ma...@jakarta.apache.org>
>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>