Cloud Spanner is a database that is enterprise-grade, globally-distributed, and strongly consistent providing the taste of structure of relational database and horizontal scale of NoSQL, DBs—and it's one of its kind in the market.
It provides the best features of a relational database and non-relational database.
When to use:
If the application is having the requirement of having a schema, running SQL, having consistency, high availability and scalability along with replication—probably Cloud Spanner is the best solution.
Special features:
Cloud spanner | Traditional relational | Traditional non-relational | |
Schema | Yes | Yes | No |
SQL | Yes | Yes | No |
Consistency | Strong | Strong | Eventual |
Availability | High | Failover | High |
Scalability ... |