*Problem Statement *While load testing a web application, several tomcat http connector threads get stuck. Ultimatelty all the available http connector threads get exhausted and the application stops responding completely.
*Setup* I have an apache http server in front of tomcat which proxies requests to it. I am using mod_proxy_http module(I do not know the exact version. Is there an easy way to find this out?) to proxy requests to tomcat. Relevant snippet from apache httpd.conf that shows the proxy setting: ProxyPass http://localhost:8080/ retry=0 ProxyPassReverse http://myserver/ *Observations* Since there is no explicit timeout set along with the proxy directive, it assumes a default value of 300s. Thus, after 300s, if apache does not get back a response from tomcat, it servers a HTTP 502 error code back to the user. However, the corresponding http connector thread does not terminate and continues waiting for a response. As a result, with time a lot of http connector threads get stuck and ultimately the whole pool gets exhausted. Http connector settings from tomcat server.xml: <Connector port="8080" maxHttpHeaderSize="8192" maxThreads="300" minSpareThreads="25" maxSpareThreads="77" enableLookups="false" redirectPort="8443" acceptCount="256" connectionTimeout="300000" disableUploadTimeout="true" /> *Questions* 1. What does the connectionTimeout attribute in the tomcat http connector do? Does it not terminate the thread if it is still processing the request once the timeout expires? I assume it does NOT and that is why I am seeing this problem. 2. Can some other configuration be added that forces the http connector thread to terminate after a certain time interval has elapsed? 3. Any other thoughts or advice to solve this problem? I know I should investigate why the http connector thread does not return a response even in as long as 300s, but assuming there is a bug in the application code shouldn't there be a settings in tomcat that prevents such application bugs from exhausting all tomcat connector threads? *Other System Information* Server version: Apache Tomcat/5.5.27 Server built: Aug 28 2008 10:08:26 Server number: 5.5.27.0 OS Name: SunOS OS Version: 5.10 Architecture: x86 JVM Version: 1.5.0_14-b03 JVM Vendor: Sun Microsystems Inc. Apache Server version: Apache/2.2.9 (Unix) Your thoughts and advice on this would be much appreciated. Thanks Anurag ------------------------------------------------------------------ Anurag Kapur Associate - Technology, Sapient Corporation. http://www.linkedin.com/in/anuragkapur http://www.google.com/profiles/anuragkapur ------------------------------------------------------------------
