> That's probably due to a very small size of the Paging Space of the AIX machine you used for testing.

That is the case, the machine has 160GB of memory and 1GB of paging space. I guess it is configured specifically for not freezing.


> About PSALLOC=early , I confirm that it perfectly fixes the issue.

I'm surprised, because it is unspeakably slow on this machine,
even with the skips in place:

PSALLOC=early time ./python -m test -uall test_decimal

I hit Ctrl-C after 10min, so it takes even longer:

Real   622.11
User   11.63
System 350.12  (!)



The -bmaxdata approach has no speed penalty. Note that you can
use 10 petabytes for the value, it should still prevent this issue.