So, I have been getting a "database error" problem on my site, and I have been searching through the forums for a thread that matches my issues, but I haven't found any.
I run a blog (replacementlevelredsox.com) which gets about 500-1000 hits per day. It's hosted through dreamhost. I had been running it on a shared server, but it got very slow during high traffic periods (during baseball games, basically), so I switched to a VPS. On the VPS, speed has been wonderful, but I started getting occasional and now regular "error establishing a database connection."
I am running W3 Total Cache and I have been clearing out post revisions and other extra crap from the database. I am running several other plugins, but I have tried deactivating and activating them and nothing has prevented the database errors problem. I did run a performance check on the plugins and cleared out those that were eating a lot of RAM, those that remains don't appear to be creating the problem.
I went into the MySQL side of the database and found very high numbers of "handler_read_rnd_next" and "select_full_join", among others. MySQL said that was related to having too many tables without an index, and some people on the internet said was related to having permalinks read as just /%postname%/, which apparently prevents indexing somehow. So I have switched the permalink structure as well.
None of these changes have stopped the regular database errors. Any help you can offer would be greatly appreciated.