Over the past week, using I have had a number of permanent hangs (about four, with "permanent" meaning hours if left alone) in the following general situation.
I have been editing SQL, running a single statement with Alt-Enter, then executing another action, such as running a different statement in the same query, or toggling the !fullfetch directive.
In some cases I have initiated the second action without waiting for the first to return all of its results. (I am unsure whether this is a supported scenario, but it is permitted.) In other cases, such as the case that just occurred,* I did wait for the first statement to finish returning results, before toggling !fullfetch on (it was previously off).
[*Correction: the present case was not a permanent hang. It lasted only long enough for me to write this post. (I'm a slow writer.) Manifold is back now.]
The queries have generally included a VALUE statement defining one or more source tables. They have usually or always involved tables in a temporary child database (the visible kind).
I am becoming extremely careful about exporting my code.
This is at least with build 22.214.171.124, possibly also with 126.96.36.199 (not sure).
I'm not sure I've got enough detail to send a report to Tech yet.
Can other people keep an eye out for this sort of behaviour, and add a notes if they see it too? I'll post if it happens again.