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From Perrin Harkins <phark...@gmail.com>
Subject Re: Disconnect database connection after idle timeout
Date Thu, 13 Nov 2014 22:49:26 GMT
On Thu, Nov 13, 2014 at 5:38 PM, Xinhuan Zheng <xzheng@christianbook.com>
wrote:

> We have load balancer cache that can cache images and JavaScripts. This
> functions seems a bit duplicate.


It's not about caching. Here's a quote from that link I sent earlier:

"Another drawback of this approach is that when serving output to a client
with a slow connection, the huge mod_perl-enabled server process (with all
of its system resources) will be tied up until the response is completely
written to the client. While it might take a few milliseconds for your
script to complete the request, there is a chance it will be still busy for
some number of seconds or even minutes if the request is from a slow
connection client."

You might think everyone has fast connections now so this won't matter, but
it does. It's especially bad if you have keep-alive on for the apache
server running mod_perl, since that means your large mod_perl processes sit
around for some extra time doing nothing, while holding onto their database
connections. Install a front-end proxy, turn off keep-alive  on your
mod_perl and reduce your max idle servers, and watch what happens.

- Perrin

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