New attempts to load an already existing layer from a persistent key-value store (with a number of memory layers from a journal).

DefaultBufferSize is the default memory allowance of node buffer that aggregates the writes from above until it's flushed into the disk.

Defaults contains default settings for Ethereum mainnet.

ReadOnly is the config in order to open database in read only mode.

Config contains the settings for database.

Database is a multiple-layered structure for maintaining in-memory trie nodes.