Hello. We have an existing Apache server (version 2.4.25 on Debian stretch) hosting a web application on which we want to activate mod_http2. The Apache server is only a reverse HTTP proxy (using mpm_event) on our application . We followed the instructions (http://httpd.apache.org/docs/2.4/en/howto/http2.html) to do the setup and it seemed to work at first. Our application uses a persistent Server Side Event request per browser tab (which is the main reason we want to switch to http/2). This persistent request is managed by pushpin (https://pushpin.org).
When several users play with the application for a while and open several browser tabs, some requests get stuck and stay in "pending" state forever. When a browser tab gets stuck, all further requests are stuck in other tabs too. What we've tried: - increasing H2MaxWorkers to 120 (more than the number of users*number of browser tabs) improves the behavior but we still get some stuck requests - with H2MaxWorkers = 3 we get stuck requests with only a small number of opened browser tabs - updating Apache to 2.4.43 still get stuck requests - when mod_http2 is disabled we do not get stuck requests - if we do not keep persistent SSE requests we do not get stuck requests - changing the mpm to mpm_worker also seems to improve the situation: we get stuck requests but the response comes back with a delay (some seconds). The Apache error log (LogLevel warn) does not print anything when stuck requests occur. We understand that each persistent request occupies a mod_http2 worker, but not why this has an effect on other requests. Would somebody have an idea to explain this behavior? I can provide detailed logs and other information on our setup if needed. Sébastien Grignard. Algoo SAS --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
