Time to give devs a training course on SQL admin.

Backup history is in MSDB backuphistory table.

Cached plans don't contain the degree of parallelism. If there's a parallel query in cache, it's the query execution engine which decides what DOP to use or whether to discard...

Break it, no. However to restore you'd need that log backup file.

I can understand devs taking ad-hoc full backups (though they shouldn't have sufficient rights on production to do that),...

Differential and log backups can run at the same time, there's no problems doing so.

Statistics have no dependency on parallelism or lack thereof.

Full backups do not and never have broken the log chain.

No conflict.

Maxdop query hint overrides the server Maxdop setting.

If resource governor is enabled and a Maxdop is set via resource governor, then that is the max value allowed. A query...

Your suggested index is not a replacement for the other two. It may be good enough for your workload, but you should test carefully.

Part of it will depend on how...

The query is reading just over 14 million rows and aggregating that down to 1099. If it's reading 14 million rows from a table (the rows which satisfy the where...

How many rows total in the table?

You told me earlier that there were 1099 rows which qualified for the where clause, but the plan shows 14 million rows being returned...

I suppose you could loop over each database and query sys.sql_modules. But the Generate Scripts option I mentioned is Management Studio functionality, not a SQL command.

Because it means that SQL uses TempDB to allocate that temporary work space, not your user database. It means you...

In the user database, where indexes always reside.

The Sort in TempDB option changes where SQL allocates temporary work space from,...

Go have a chat with your DBA and ask why the option was changed. It could be a security requirement that it be disabled.

If he's logged in with SQL authentication, the SQL username is all that you can get. If you want to get the windows logins, require people to use windows authentication.