Often among the hardest of my decisions is whether I should spend more time trying to simplify a given problem by eliminating additional factors, shrinking the data needed for a repro, etc… or just put all that effort into investigation purely aimed at understanding the behavior. I expect that to be a long-term challenge 🙂
I was quite happy with the way this particular one worked out, though. It started as a maze… access violations generated on a SQL Server 2016 instance with dozens of databases. The access violation came from an insert query using a synonym – with the underlying table in another database! (I didn’t know that was possible – or *ever* desirable – until I saw it in this context.) The AV was occurring during a multi-step data transfer process and it was hard to isolate the data flowing into and out of the two databases in question. But after some finagling, I got the problem repro pretty doggone small. Reproduced the AVs on several CUs of SQL Server 2016 and on SQL Server 2017 RC2.
If you think you’re going to enlist the help of someone outside your organization, then you definitely want a minimalistic repro. That will reduce the risk of red herrings, reduce the burden of assistance, and make it much more likely that some poor sap in support can actually fix your problem if it turns out to be a bug.