Issue 159

[naomijub]

This is the issue of using too much space for caching. There were 2 solutions being explored:

1. Remove state caching and do all IOs for select queries (this increase time to query by ~30%)
2. Keep it as is having a giant heap memory consumption and giant file being written.

The solutions was neither...
Now the state is being converted to Vec<u8> and the file size reduced to half and the memory consumption to 35%.
994504 bytes - 2021_04_16.log
401719 bytes - local_data.log file containing all the caching info (it was larger than 2021_04_16.log before.

Performance decrease can be found in benchmark file diff

Related to issue #159