Cloud Spanner is another Relational Database management service provided by GCP. This is different from Cloud SQL in many aspects, such as:
- It is a Google Proprietary technology (no open source)
- Costlier
- Stronger ACID values (ACID++)
- More reliable
- More relational
- More transaction specific
- Fully managed
You ought to pick Spanner over Cloud SQL in use cases involving the following:
- Data sizes exceeding 10 TB
- Heavy usage, with QPS (queries per second) exceeding 5K
- Users in multiple regions (spanner has replication across regions, Cloud SQL is regional)
The technology behind Cloud Spanner is cutting edge. Unlike traditional RDBMS, here rows with the same primary key (which are the most related ones in most cases of transactional applications) are brought together and converted into a new entity called a split. Each split is replicated multiple times over failure...
