Storage Optimization 1: Measuring Write Amplification

[maxwong]

Is your feature request related to a problem? Please describe.
Referring to #45 , this thread processes the following question:
Measuring write amplification.

Describe the solution you'd like
Writes different size of data in different number of keys to measure the amplification scale.

Describe alternatives you've considered

Additional context
We are using lmdb as storage engine. Will measure different engines to collect data and to compare.

[maxwong]

Preliminary tests indicates that storage usage is quite stable. Write amplification is at 1x level.
LMDB is a Copy-On-Write, B+ tree based storage engine. So the write amplification is quite stable (write size + log of data key size).

The storage engine used is LMDB. Found 2 articles (an open debate?):
Paul Banks - LMDB: The Leveldb Killer?
Response by the LMDB developer

These give us a better understanding of LMDB design considerations.