Re: Minor optimizations in lazy_scan_heap

You're right. These are not big ticket optimisations, still I felt they are worth doing because tiny bits add up over a time and also because the code may become little simpler. The benchmarks don't show anything interesting though. The time taken to scan 100K+ bits is sub-second. So even when I tried with the attached patch, the numbers did not show any noticeable difference. It might be worth trying with a table with 1M or 10M data blocks, but I don't have such a hardware to test.

The patch itself can be improved further, especially we can possibly optimise the loop and test 32-bits at a time, instead of 8 I am doing currently. Not sure its worth though.