Why are you using auto close?
One example of what is generally thought of this setting.
Unless you have a well documented reason with a lot of testing...

With the DISTINCT aggregation operation in addition to the GROUP BY operation but no filtering at all, you're going to be somewhat dependent on hardware (mostly memory & disk) to...

Just guessing (which is frequently unhelpful, it's why everyone is asking you to post the code), your functions. Are they by chance multi-statement table-valued functions? If so, those are notoriously...

Probably too late to do this now, but it'll prove handy for any new upgrades you do.

Moving to 2016, the Query Store is your best friend. Move the...

Mostly, I stick to the metrics supplied by the portal along with monitoring wait stats within the database (sys.dm_db_wait_stats) and using extended events to capture query metrics when needed. The...

If you're not specifically monitoring for recompiles, there's no for sure way to know why it happened. Now, you can understand why the plan changed. It generally comes from three...

Commiserations you mean.

I promise to cause marginally...

Extended Events have a mechanism for doing this. First, you need two events (or maybe three), rpc_completed (and/or sql_batch_completed, or even one of the statement completed events) and the wait_completed...