"PDOException: SQLSTATE[42000] [1203] User bryanbra_drp1 already has more than 'max_user_connections' active connections in lock_may_be_available() (line 167 of /home4/bryanbra/public_html/includes/lock.inc)."
...is the punch line or not.
Heh, its a rant on Drupal. So the author is using Gmail as a "good thing" that would be made into a "bad thing" if it were implemented in Drupal.
Meta comment, I wonder when people using Gmail as an example of 'good' will figure out it doesn't have quite the approval rating they were thinking it had. Actual comment, its a known issue that programmers write things they like to use, not things other people like to use. It is one of the reasons programmers have an easier time figuring out modern technology that was built by other programmers, they already speak the underlying conceptual language. It is hard to see that gap unless you are a non-programmer.
But people here are funny: "oh, it is giving max_user_connections errors, let me keep refreshing the page to see if it shows up"
Even with pages cached in Memcache, Drupal would open a DB connection by default (it's possible to override this using page_cache_without_database, but not everyone is going to do that).
Using something like Varnish as the primary page caching mechanism would work around this, albeit with some trade-offs.
Generally though, the fault with issues like this is often that the MySQL connection limit is set lower than it needs to be. Often, this is set at a level far below that which would actually cause the DB server to become overloaded, and it just starts rejecting further connections even if capacity exists to handle more.
EDIT: typos
Some sites I have had to deal with on initial inspection have 250+ queries per user (sometimes the same ones over and over due to plugins/modules) and people wonder why after 10 users it breaks the database/site.
Without cache on wordpress you might be in trouble, without cache on Drupal you don't run.
Still, Drupal is orders of magnitude more useable than other PHP frameworks like Joomla. The PHP that is fun is using microframeworks like limonade, flight etc if PHP is used.
Page runs on Drupal > Drupal uses database > Database connections were exhausted. I was suggesting caching up front to bypass calls to the database (not specifying a particular piece of caching software).
At the time I was looking at the page through a 3rd party cache. I didn't realise the page had inline comments, those would of course complicate the problem.