Google Cloud Spanner vs MySQL: What are the differences?

Introduction: Google Cloud Spanner and MySQL are both popular database management systems used for storing and retrieving data. However, there are several key differences between the two.

1. Scalability and Distribution: One major difference between Google Cloud Spanner and MySQL is their scalability and distribution capabilities. Google Cloud Spanner is a globally distributed, horizontally-scalable database system that can span multiple regions and continents. It automatically handles sharding and replication, allowing for high availability and scalability. On the other hand, MySQL is primarily a single-server relational database system, although it supports replication and clustering for limited distribution.

2. Consistency and ACID Compliance: Another difference is the level of consistency and ACID compliance provided by Google Cloud Spanner and MySQL. Google Cloud Spanner guarantees strict external consistency and provides strong ACID semantics across distributed transactions. This means that queries always return the latest committed data, regardless of the location or speed of the write. In comparison, MySQL offers a range of isolation levels but may sacrifice some consistency guarantees in favor of higher performance.

3. Schema Changes: Google Cloud Spanner and MySQL also differ in their approach to schema changes. Google Cloud Spanner supports schema evolution without downtime by allowing online schema updates, such as adding or modifying columns, indexes, and constraints. It automatically handles data migration and maintains high availability during the process. In contrast, MySQL requires downtime or complicated manual steps to alter the schema, potentially causing interruptions and impacting availability.

4. Performance and Scale: Google Cloud Spanner is designed to handle high-performance, globally-distributed workloads, making it well-suited for large-scale applications with high throughput and low latency requirements. It can handle millions of transactions per second across thousands of nodes. On the other hand, while MySQL is also capable of scaling and supporting high-performance workloads, it may require additional configuration and optimization to achieve comparable performance at such a large scale.

5. Built-in Replication and Backup: Google Cloud Spanner provides built-in replication and backups as part of its architecture, ensuring data durability and high availability. It automatically replicates data across multiple regions and maintains synchronous copies, allowing for failover and recovery in case of failures. MySQL, on the other hand, requires manual configuration and additional tools to set up replication and backups, which can be more complex and time-consuming.

6. Pricing Model: Lastly, Google Cloud Spanner and MySQL have different pricing models. Google Cloud Spanner is a fully-managed service that charges based on usage, including storage, read and write operations, and network egress. It offers pricing options for different levels of performance and availability. MySQL, on the other hand, is an open-source database system that is free to use, but may require additional hardware, software, and maintenance costs, especially for enterprise deployments.

In summary, Google Cloud Spanner and MySQL differ in scalability, consistency, schema changes, performance, replication, and pricing. Google Cloud Spanner provides a globally-distributed, highly-scalable, and ACID-compliant database system with built-in replication and online schema updates, while MySQL is a single-server relational database system that requires additional configuration and may sacrifice some consistency for performance.