Re[3]: memory and/or ms problem
hi randy, thanks for your tips!
i think i found the reason for the growing memory consumption of my
servlets.
preconditions:
i use servlets to get data out and in a mysql database and generate
html pages with PrintWriter.print(...) statements.
my servlets often use:
...
Statement Stmt = C.createStatement();
ResultSet RS = Stmt.executeQuery("SELECT ..,..,.. from ..");
while (RS.next())
{
//do something with data
out.println();
}
...
on each request an instance of a servlet is created and the servlet
starts reading data out of the database and writes it in the
PrintWriter stream.
But what happens if the PrintWriter has no target (because the user
sends another request or more then one other requests)? I am not sure,
but it seems that the servlet tries to write to the PrintWriter stream
and has no success. the result is a growing amount of instances of a
servlet which try to write to a PrintWriter and have no success. and
it seems they keep try writing (and consuming memory) a long time ...
my solution is to check the error state of a Printwriter before
writing in it. so the code from above looks like this:
...
Statement Stmt = C.createStatement();
ResultSet RS = Stmt.executeQuery("SELECT ..,..,.. from ..");
while (RS.next())
{
if (out.checkError()) break;
//do something with data
out.println();
}
...
for my application it seems to work, but i think there must be a better
way,
(why does the write statement throws an exception and the print
statement not?)
any ideas?
Gerd
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memory and/or ms problem
Hi tomcat-users, I am having some memory related troubles with my servlets running on tomcat 3.2.1 on an win nt 4 workstation machine. I read all previous messages in the list with the term "memory" in it, but everything i try does not help. problem: the memory consumption of the java.exe increases slightly, the over all memory consumption of the system increases fast and memory is not released. after a week (and about 400 hits or so) the server runs out of memory (tomcat gives a OutOfMemoryError and quits). what i did: - set java max heap size (nothing changed) - set max_threads (30), max_spare_threads(20) and min_spare_threads(5) for both http and https ConnectionHandler - set session-timeout to 1 Minute - added System.gc() to end of every servlet my application uses servlets and mysql, i close every mysql connection and i am not able to find anything i could change to get the memory freed. I also use ms-stresstool and i can simulate this memory-problem. could anyone give me some assistance please? thanks, Gerd - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
Re: memory and/or ms problem
I have the same problem too. I use Windows 2000 Server, Tomcat 3.2.1 and isapi_connect.dll I've already asked this question on the list, and nobody seems to know. Oleg L. Sverdlov Web Development Dept. Netmount Networks Raanana, Israel. http://www.netmount.com Phone: +972-9-745-5220 Fax: +972-9-745-2521 - Original Message - From: "Gerd Trautner" [EMAIL PROTECTED] To: "tomcat-user" [EMAIL PROTECTED] Sent: Thursday, March 01, 2001 1:16 PM Subject: memory and/or ms problem Hi tomcat-users, I am having some memory related troubles with my servlets running on tomcat 3.2.1 on an win nt 4 workstation machine. I read all previous messages in the list with the term "memory" in it, but everything i try does not help. problem: the memory consumption of the java.exe increases slightly, the over all memory consumption of the system increases fast and memory is not released. after a week (and about 400 hits or so) the server runs out of memory (tomcat gives a OutOfMemoryError and quits). what i did: - set java max heap size (nothing changed) - set max_threads (30), max_spare_threads(20) and min_spare_threads(5) for both http and https ConnectionHandler - set session-timeout to 1 Minute - added System.gc() to end of every servlet my application uses servlets and mysql, i close every mysql connection and i am not able to find anything i could change to get the memory freed. I also use ms-stresstool and i can simulate this memory-problem. could anyone give me some assistance please? thanks, Gerd
Re[2]: memory and/or ms problem
Hi Randy, Thursday, March 01, 2001, 1:15:06 PM, you wrote: RL Look at your code. My experience has been that Tomcat doesn't leak RL any memory. Check that you haven't set your sessions to never time out RL (otherwise each session will continue to collect digital dust). Also check RL that you don't have any structures in memory of static classes that continue RL to grow with each request (in-memory logs that flush to disk when some event RL happens would one example of a place to look). Did some additional test and: you are rigth, something in my code is the reason for the growing memory consumption.but i can't imagine what it is. so the test i did was: stress a servlet that just writes a text. i stressed it really and nothing happend, the memory consumption growed, but gc brought it down to starting level. wondering... Gerd - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
