In 2013 a new bitcoin core was released and one of the supposed improvement was migrating from Berkeley DB to LevelDB. According to the release notes at bitcoin.org:
LevelDB, a fast, open-source, non-relational database from Google, is now used to store transaction and block indices. LevelDB works much better on machines with slow I/O and is faster in general.
Similar statements were done by bitcoin core developers:
LevelDB - an open-source rewrite of Google's own database system - was designed for efficiency and consistency on commodity hardware, and outperforms BDB by an order of magnitude in some settings. Preliminary tests with LevelDB show very good results.
However, nowadays there are several comments through the internet critizing LevelDB. According to LevelDB page at Wikipedia:
LevelDB is widely noted for being unreliable and databases it manages are prone to corruption. Academic studies of past versions of LevelDB have found that, under some file systems, the data stored in those versions of LevelDB might become inconsistent after a system crash or power failure. LevelDB corruption is so commonplace that corruption detection has to be built in to applications that use it.
In summary, the complaints about LevelDB are:
- unreliable and databases are prone to corruption
- several bugs due to fundamental flaws
- poor code quality
- no longer actively maintained (i.e. dead project)
Are these complaints about LevelDB correct?
What is the final balance of migrating Bitcoin Core from Berkeley DB to LevelDB? Is LevelDB working as expected? This migration was the right choice?