Sorry for the excessively vague title. A history store cursor open/close should not overlap with opening and closing other cursors. i.e: an operation on the history store should not:

• Require opening cursors on other tables.
• Span across an operation that can open a cursor on another table.

We made a change in WT-6339 related to transaction snapshot management that assumes the encapsulation described above is true. We should add checks to the code to enforce it, since we are relying on the behavior.

This is pretty well moot for internal sessions, but when a user session is tasked with doing operations on the history store we need to be careful not to interfere with that operation.