Steven - BTW.
If you do it the way you suggested, which is to break it into multiple SQL statements, you should consider 2 things:
1. Wrap the SQL statements in a TRANSACTION.
2. Add the UPDLOCK hint on the SELECT MAX (as I did in my example)
Then in your 2 windows test case, you don't need to introduce the WAIT. You can simply execute the first few statements just prior to the INSERT, switch windows and execute the other SQL (which will hold until you go back to the prior window and execute the final statements up to COMMIT TRANSACTION.
UPDLOCK holds the locked table until the transaction completes. In my case, since it wasn't in a transaction the lock is freed once the single statement completes.
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
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