what is a realistic value for max_user_connections on a busy site?

marcnyc

Hello, I used to be hosted on a server of a shared hosting provider. I then requested to be upgraded to one of their faster servers. The faster server they put me on is indeed faster but my scripts (SMF and a custom written one) started breaking saying there were too many simultaneous connections (more than max_user_connections would allow).

I did not have that issue on the slower machine so I asked my tech support to set the new server to 0 (unlimited) but they wouldn't allow that to avoid too big of a server load and they asked me how many I actually needed.

My question is: what is a realistic value for me to ask?

These are the stats for the site's latest access:

Successful requests: 61,553
Average successful requests per day: 19,151
Successful requests for pages: 720
Average successful requests for pages per day: 223
Failed requests: 3,071
Redirected requests: 130
Distinct files requested: 11,724
Distinct hosts served: 3,878
Data transferred: 867.83 megabytes
Average data transferred per day: 270.03 megabytes

sneakyimp

I'm guessing that max_user_connections is referring to mysql? If not, you need to be clearer about your question.

I have found that it's WAY TOO EASY to get the 'too many connections' error if you use persistent connections with mysql_pconnect() than if you just use mysql_connect. Check for that.

Otherwise, 50 might be fine. It doesn't sound like you are anywhere near this amount. You are getting only 223 page requests per day on average? That's less than 10 per hour.

Given that you are averaging 1.21 MB per page access, the number of connections could be due to the fact that you are retrieving so much data and users are taking all day to download? I still think 50 is going to be fine but 1.21 MB per page access is a lot.

Sxooter

Yeah, what sneakyimp said makes sense.

If you're using pconnect, stop.

If you can't stop, then make sure that mysql's max connections is higher than apache's max children / threads settings. i.e. if apache can spawn a total of 200 children, and mysql is set to handle 50 connections max, you'll get this problem. Either lower apache or raise mysql's setting.

marcnyc

Yes it's a MySQL server and I thought that was the problem but after I contact tech support of the server they said this:

"Max_user.. has not been changed its still the same and its set to a high number (it is not however unlimited). There was some other issue with an sql named pipe which was most likely the reason for your problem. The l3 tech on hand took care of it."