Indexes

Log-Structured Merge Tree

BadgerDB supports a LSM tree, where keys are stored in the LSM and values are store in a write-ahead log called a value log. Since key tend to be smaller than values, this allows the system to maintain a smaller LSM tree. To allow efficient access, the LSM make sure to maintain a sorted order, making range queries easier to process, as well.

Storage Organization

Log-structured Sorted Files

BadgerDB uses a sorted LSMs to support a key-value store storage organization[?].

Query Interface

Custom API

The query interface for BadgerDB is in Go since the system was originally created to provide a good key-value store that can easily be accessed through Go without having to go through Ggo.

Compression

Delta Encoding

BadgerDB uses delta encoding to reduce the size of keys, to further reduce the size of the LSMs. Also, during a read, a fingerprint of the key is stored rather than the key itself to also save space.

Views

Not Supported

I do not think BadgerDB supports views.

System Architecture

Embedded

Concurrency Control

Multi-version Concurrency Control (MVCC)

Badger supports ACID transactions and Multi-Version Concurrency Control with Snapshot Isolation. Badger acquires locks on directories when accessing data, so multiple processes cannot open the same database at the same time.

Data Model

Key/Value

Badger’s underlying functionality is an efficient key-value store.

Stored Procedures

Not Supported

I do not think BadgerDB supports stored procedures.

Isolation Levels

Serializable Snapshot Isolation

BadgerDB supports snapshot isolation. Badger also has read-only transactions (called Views), that ensures a consistent view of the database system, and that will not include changes made by an uncommitted transaction at the start of this transactions. With read-write transactions, if a conflict occurs, the transaction will written with an error notifying the user of a conflict, giving the user the option to retry the transaction.

Storage Architecture

In-Memory

BadgerDB is an in-memory DBMS, that supports larger-than-memory databases by writing to disk. Disk is also used to make the BadgerDB persistent and resilient.