Actually, increase 'heap memory' indeed works. When I use 2K page size and 8K heap memory per user, my loading last about 1.5h. And when I increase to 256K, it lasts about over 30h and failed as well.
What concerns me is even it's failed, I ended the 'isql' process, why didn't the heap memory got released? I can't do anything with the error. Only have to restart the ASE.
How can I clean up heap memory by commands or look up the heap memory usage. @@heapmemsize seems never changed and only the algorithm shows in Sybase document.