Are intra-query parallelism deadlocks a thing?

[Breck_Carter]

Today's Consipiracy Theory is brought to you by this ancient SQL Server blog post: Today's Annoyingly-Unwieldy Term: "Intra-Query Parallel Thread Deadlocks"

I know SQL Server isn't the same as SQL Anywhere, but... they both have a lot of the same features.

So, here goes...

Is it possible for SQL Anywhere intra-query parallelism INT:Exchange connections to be involved in thread deadlocks that are silently "handled" by killing one or more INT:Exchange connections?

Is it possible for such thread deadlocks to go unnoticed because INT:Exchange connections don't have human users so there's nobody who will notice they've gone missing?

Is it possible for such thread deadlocks to be the cause of server outages sometimes associated with runaway intra-query parallelism usage?

Is this a good reason to add deadlock diagnosis via sa_report_deadlocks() to databases where max_query_tasks is something other than 1?

( this topic came up during research on a possible new Foxhound Alert and/or Flag to detect intra-query parallelism on servers that are really too busy for such shenanigans 🙂