Mine! (again, unless there's another taker)

I'll take it, unless there's someone else who wants it desperately. I need a reason to play with it.

The CTAS statements will...

It's SQL Server Parallel Data Warehouse aka APS, or the Azure version of it, Azure DWH. CTAS...

There should be a time in the XML, it'll be an attribute of the event tag.

Work through the method described here: https://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-1/

Yes, it's out of date, no I haven't got around to updating it with Extended Events. It's still valid, you can use Extended Events...

Be careful. Data-accessing scalar functions can be horrifically slow. Avoid using it in a select/insert/update/delete and it should be OK.

Have you got any evidence that spinlocks are the problem, as opposed to inefficient queries?

For anyone reading this who doesn't memorise error numbers.

Error 833: SQL Server has encountered <n> occurrence(s) of I/O requests taking longer than 15 seconds to complete on file [<full path...

Err, no. It means exactly what I said, separate IO subsystems.

No. SQL's rules are that data modification statements are atomic, they either complete entirely or fail entirely.

You'll need extra logic in the insert to ensure that SQL only tries to...

DROP_EXISTING and ONLINE aren't properties of an index. They're just options you put onto create or alter index to change the way that statement behaves. They don't persist, they have...

Put a new line inside you code tags (which is a good idea in general, for readability)

select a.*, (select max(Startdate)

from @b-2 b

where b.id=a.id and...

What exactly do you mean by 'relational index options'?

Is that in an MS Access form/report?