Memory growing during scan

[kilian]

Reported by Jan Strube:

Memory usage grows during a straightforward parameter scan with integration. Can become a problem if the scan is very fine-grained.

[kilian]

Just trying to reproduce ...

[kilian]

Reproduced.

IIRC, new processes (runs) are always appended to the process stack, so the linear grow is expected. The process stack is global, not local to the scan iteration. But I have to check this.

I never thought about a number of runs that large. In the present context, it makes sense to delete results that are obtained within a scan iteration. Maybe process/run records should be treated as strictly local ... but this is not that easy to implement.

[kilian]

I'll make the process (run) stack local to local environments. This will hide their results completely from the global environment, but previously it was only the last scan iteration that was accessible, anyway. There should be arrays of Sindarin objects to catch individual scan results, but that's a different issue.

[kilian]

The main leak should be fixed with r6103. I still see some leakage, but less severe. For now, I close the ticket as duplicate, referring to it in #623.