My experience (~25 years as a SQL Server only consultant) shows that suboptimal IO is the cause of this. You can also add in suboptimal virtual machine configuration these days...

You are welcome. 

The answer to your question will be found in the query plan.

You need to CROSS APPLY with a new construct that has each year you want data for. VALUES would be what I use. Your @tax table will never give you...

Wait - am I seeing correctly that your sproc actually creates the log record? If so, why isn't it simply putting the database info in the row it creates?

Look up CONVERT_IMPLICIT and see if that is in play here.

I note that in my almost 25 years of consulting on SQL Server MISMATCHED DATA...

That is unacceptable in my book and should...

Not much documentation to be found readily about those elements. But logically what you say sounds correct. 

HOWEVER, I would be WAY less worried about the fact that you...

It is VERY seldom advisable to mess with that setting. 

What does sp_whoisactive show for current activity and spid status?

What changed from when this did type of...

10% growth is BAD, especially for tlog which MUST be zeroed on growth (as opposed to data file which could be IFI'd).

Whenever you decide you need to bring...

Having different RECORDS doesn't mean they don't have one or more identical VALUES in the 3 indexed fields. You can still get a collision that way, no?

I can absolutely guarantee you that triggers and TSQL to process records can be crafted to have as low of an overhead as you desire. I have done this on...

This is one of the very few times I will disagree with Gail. I would stay away from replication in any case where possible, and I am certain that it...