# Mongrel + Apache occasional Proxy Error

**URL:** <https://www.ruby-forum.com/t/mongrel-apache-occasional-proxy-error/149182>\
**Category:** Mongrel\
**Created:** [September 22, 2008, 10:52am UTC](https://www.ruby-forum.com/t/mongrel-apache-occasional-proxy-error/149182 "2008-09-22T10:52:38Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![cpher](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/2bfe46/32.png) [@cpher](https://www.ruby-forum.com/u/cpher)\
**Post date:** [September 22, 2008, 10:52am UTC](https://www.ruby-forum.com/t/mongrel-apache-occasional-proxy-error/149182/1 "2008-09-22T10:52:38Z")

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Hi There - long time reader first time poster 😛

I appreciate this is a problem with quite a few threads out there, but I  
have read many of the threads and tried many of the fixes / hacks  
suggested to no avail.

I have taken over looking after a server that is running 6 rails  
applications, each with up to 3 mongrels each. The apps each use a local  
mysql database.

Every few days or sometimes more frequently I get the infuriating error  
from some of the apps:

========================

Proxy Error

The proxy server recieved an invalid response from an upstream server.  
The proxy could not handle the request GET /

Reason: Error reading from remote server

========================

I have read many threads and tried adding the following to the vhost  
file for each cluster:

\<VirtualHost \*\>  
SetEnv force-proxy-request-1.0 1  
SetEnv proxy-nokeepalive 1

This did not seem to solve the issue unfortunately. I have the mysql gem  
installed (ver 2.7). When I log into mysql and run the “show full  
processlist” there are a lot of SLEEP commands with a TIME value ranging  
from 100 - 3000. It looks like there is one for each mongrel in each  
cluster. I am not sure if this is normal behavior for the mysql gem? Is  
there any way of finding out whether rails is using the mysql gem? Can  
the gem be installed but rails still be using the ruby drivers instead  
of the gem?

I am not even sure if it is a mysql issue, but mysql seems to be the  
first port of call for fixing the proxy errors.

I have been banging y head against this for weeks now and am completely  
out of ideas!

Any help would be most appreciated!

Key Info:

OS: CentOS 5  
Apache: Apache/2.0.52  
MySQL: Ver 14.7 Distrib 4.1.20 GEM: mysql (2.7)  
Ruby: ruby 1.8.6  
Rails rails (2.1.0, 1.2.4, 1.2.3) (Apps using 2.1.0)  
Mongrel: 1.1.5

Thanks guys!