Re:If Gmail were built with Drupal
by rjknight on Tuesday November 12, 2013 @09:24AM
(#6717940)
No, but Drupal's out-of-the-box page cache caches pages in... the database.
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.
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