Buggy behavior and heap size

I opened a ticket about it but then I thought that maybe it would be interesting for someone else. Let me describe the problem:

When I try to make a nested extraction (i.e., an entire forum with threads, and each thread alone), websundew SE shows that the maximum heap size is 64Mb. It reaches quickly that maximum, and for then onwards the program works very, very slowly.

I didn't have a JVM installed in the PC, websundew installed one I guess

What can I do in order to increase heap size? Does it help in order to raise the speed of a complex extraction?

After 30 minutes, websundew just processed 29 pages and 261 r4egisters of a multilevel extraction (a forum and the content of its individual threads). I'm sure that the program can work better