Comments on: Cool, Tomcat is able to handle more than 13,000 concurrent connections.

By: Myšlenky dne otce Fura » Blog Archive » jOpenSpace 2010

Myšlenky dne otce Fura » Blog Archive » jOpenSpace 2010 — Sun, 14 Aug 2011 18:55:59 +0000

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By: Pramod MUdgal

Pramod MUdgal — Thu, 23 Jun 2011 00:12:19 +0000

I am working on windows machine. When i run the above example, it does not create more than 200 connection. Than i separately tested that on my machine more than 7000 threads can be spawned. What changes should i make this example work for around 1500 concurrent connection. I have to create a proof of concept for 1500 simultaneous connections. Thanks.

By: sasol

sasol — Tue, 22 Mar 2011 21:29:34 +0000

Tried on glassfish 3.0.1, reached ~9000, but i'm no expert in tweaking gf.
Strange thing is that 'Too many open files' problem rises upon gf boot not while running the test. When thread pool is large it also causes OutOfMemory on boot time. So it's hard to find optimal configuration, fo example:
when max-pool-size=9000 test reaches 9000 threads, but when you set max-pool-size=19000 test reaches only ~6000 because of HeapSize limit.

By: Joan Simpson

Joan Simpson — Fri, 01 Oct 2010 14:08:24 +0000

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By: Matt Hudson

Matt Hudson — Wed, 08 Sep 2010 10:08:11 +0000

Great article, helped me greatly troubleshoot our openSUSE11.2 tomcat woes!

By: Olivier

Olivier — Mon, 02 Aug 2010 15:02:26 +0000

Servlet no. 28232 called.
Servlet no. 28233 called.
Servlet no. 28234 called.
Reached 28234 of connections
java.net.NoRouteToHostException: Cannot assign requested address

My configuration :
Hardware : HP DL580 4 cpu (QuadCore) with 8 Gb RAM
System : Linux CentOS 64 Bits
Apps : Tomcat 6.0.28 with OpenJDK Runtime Environment (IcedTea6 1.6)

By: Java crumbs » Blog Archive » More than 16,000 connections in Tomcat

Java crumbs » Blog Archive » More than 16,000 connections in Tomcat — Thu, 06 May 2010 12:19:32 +0000

[...] Java crumbs Short remarks from Java world « Cool, Tomcat is able to handle more than 13,000 concurrent connections. [...]

By: Lukáš Křečan

Lukáš Křečan — Wed, 05 May 2010 15:18:26 +0000

@IA Thanks for your questions, I will try to answer them
1) Yes
2) For 5000 open connections the Java process consumes 1.3GiB of memory, heap size is 1,040,187,392 B and 615,365,326 B of heap is actually used.
3) I have not tried yet, Size of some of the buffers can not be changed.
4) I have not tried (yet), heap is the bottleneck. Stacks are allocated somewhere else.
5) Interesting idea, I will try to change it and will let you know.

By: IA

IA — Wed, 05 May 2010 12:22:25 +0000

I really like this topic. I'm more focused on desktop java so I'll not play with tomcat, but I have some questions and suggestions.
- was the JVM process 64bit?
- how much memory was allocated by the JVM? and by heap?
- it looks that one connection consumes about 100kB mem in byte and char arrays, how much it took with smaller buffers?
- have you tried to change the stack size? maybe it can make significant differences
- maybe it does nothing, but can you try to reduce the string concat in your example?

By: lzap

lzap — Sun, 02 May 2010 14:16:28 +0000

Nicely done! Thanks