Re: too many connections issue

[James Day]

I think the maximum in the compiled versions MySQL AB supplies is 4,000 but it can be higher if you compile it yourself. For a top 150 web site with non-persistent connections, only problems have resulted in me seeing more than 1,000 connections and the server is set to allow 2,000. The application doesn't use persistent connections.

If you're seeing the error, increase the number of connections allowed and/or decrease the timeout. If you do find the timeout being necessary, look to see why the connections are staying open because it may be a bug in your application if you aren't a company running the server for web hosting. If you find that you can't handle the number of connections you get, use the slow query log or mytop with the i switch to show long running connections first and then try to optimise those queries. If your server becomes very sensitive and starts to accumulate many connections very quickly when a slow query happens, it's probably overloaded - handling too many queries which are taking too long. Optimising the queries or adding database slaves and modifying the application to support them are common ways to handle that.