My new favorite open source project

I have a very strong background in databases as I started my career as Oracle DBA then moved to Cloud and Big Data. Now, I am learning and sharing more on Blockchain. I did forget to mention that NoSql is also one of the areas of interest. Personally, I heart Apache Cassandra but now, there is more love for LevelDB.

Why LevelDB?
LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values. Source: https://github.com/google/leveldb

Now, go to https://github.com/bitcoin/bitcoin and search for leveldb or click https://github.com/bitcoin/bitcoin/search?utf8=%E2%9C%93&q=leveldb&type=

You have to read this thread to learn more about Bitcoin and leveldb. LevelDB is being used to store the chain state. https://en.bitcoin.it/wiki/Bitcoin_Core_0.11_(ch_2):_Data_Storage#Use_of_LevelDB
Initially, it was started with SqlLite (Definitely not production ready database) but then (Glad) it moved to LevelDB 
http://bitcoin-development.narkive.com/XAPoxKZU/patch-switching-bitcoin-core-to-sqlite-db

As Ethereum is fork of Bitcoin so by default it uses LevelDB too
https://ethereum.stackexchange.com/questions/10509/if-a-blockchain-is-a-distributed-database-where-is-the-data