HBase vs RocksDB: What are the differences?

Introduction

HBase and RocksDB are both popular distributed database systems, but they have several key differences that differentiate them from each other. In this document, we will explore the specific differences between HBase and RocksDB.

1. Data Model: HBase is a column-oriented database that organizes data in tables and uses a row-key based data model. Each row consists of multiple columns, and columns can be grouped into column families. RocksDB, on the other hand, is a key-value store that stores data in a sorted key-value format. It does not have a concept of tables or rows like HBase.

2. Storage Layer: HBase is built on top of the Hadoop Distributed File System (HDFS) and stores its data in a distributed manner across multiple nodes. It provides fault-tolerance and high availability by replicating data to multiple nodes. RocksDB, on the other hand, is a local storage engine that stores its data on local disks or SSDs. It does not provide built-in fault-tolerance or replication capabilities like HBase.

3. Scalability: HBase is designed to scale horizontally by adding more nodes to the cluster. It automatically partitions and distributes data across the cluster, allowing for high scalability. RocksDB, on the other hand, is designed to be a single-node database and does not natively support horizontal scalability. To achieve scalability with RocksDB, users need to shard their data across multiple instances manually.

4. Consistency Model: HBase provides strong consistency guarantees and supports ACID transactions. It ensures that updates to data are atomic and isolated. RocksDB, on the other hand, is an eventually consistent database that prioritizes high write performance. It does not provide strong consistency guarantees, and updates to data may take some time to propagate across different replicas.

5. Data Access Patterns: HBase is optimized for random reads and writes and is well-suited for applications that require low latency access to individual records. It provides efficient row-level access and supports complex querying using filters and scans. RocksDB, on the other hand, is optimized for sequential reads and writes and is well-suited for applications that process large amounts of data in batches. It provides efficient range queries and supports iterators for iterating over keys in sorted order.

6. Data Durability: HBase provides durability guarantees by persisting data to disk and replicating it across multiple nodes. It also provides mechanisms for data backup and disaster recovery. RocksDB, on the other hand, relies on the underlying storage media for data durability. It does not provide built-in mechanisms for data replication or backup.

In summary, HBase and RocksDB differ in their data models, storage layers, scalability, consistency models, data access patterns, and data durability.