Google Cloud Spanner vs H2 Database: What are the differences?

Introduction

This Markdown code provides a comparison between Google Cloud Spanner and H2 Database. The key differences between the two databases are outlined below.

1. Scalability: Google Cloud Spanner is designed to be a globally distributed and highly scalable database system. It offers automatic scaling capabilities and can handle large amounts of data across multiple regions. On the other hand, H2 Database is a lightweight, embedded, and single-user database primarily suitable for small to medium-sized applications. It does not have built-in support for global scalability.

2. Consistency Model: Google Cloud Spanner uses a globally consistent and distributed ACID (Atomicity, Consistency, Isolation, Durability) transaction model. It ensures that transactions are consistently applied across all nodes, allowing strong consistency across the database. H2 Database, on the other hand, supports ACID transactions within a single JVM (Java Virtual Machine), but it does not offer distributed ACID transactions.

3. Availability and Reliability: Google Cloud Spanner provides high availability and reliability, with automatic replication and failover mechanisms. It offers a 99.999% SLA (Service Level Agreement) for global availability. H2 Database, being an embedded database, relies on the availability and reliability of the host application and does not offer built-in mechanisms for high availability or automatic replication.

4. Data Replication and Synchronization: Google Cloud Spanner automatically replicates data across multiple regions for durability and high availability. It also provides automatic data synchronization and conflict resolution. In contrast, H2 Database does not have built-in support for automatic data replication or synchronization. It relies on the application's logic or external mechanisms for data replication and synchronization.

5. Query Language Support: Google Cloud Spanner supports SQL-based queries with additional enhancements for distributed transactions and schema evolution. It allows complex queries across tables and supports advanced features like joins and aggregations. H2 Database also supports SQL queries but does not have built-in support for distributed transactions or advanced features like distributed joins.

6. In-Memory Performance: H2 Database can be configured to run in-memory, providing fast access and processing of data. It is suitable for applications that prioritize performance over durability or long-term storage. In contrast, while Google Cloud Spanner offers good performance, it does not have the same level of in-memory performance as H2 Database.

In summary, Google Cloud Spanner offers global scalability, distributed ACID transactions, high availability, automatic data replication, advanced SQL capabilities, and strong consistency. H2 Database, on the other hand, is a lightweight, single-user database with in-memory performance, suitable for small to medium-sized applications.