How do joins work in the Cloud Spanner database?

Question

How do joins work in Google's Cloud Spanner database?

Will the join query execute fast? Is there any comparison between SQL(MySql, Oracle, MSSQL) vs NewSQL(Cloud Spanner/TiDB/CockroachDB)?

Answer 1

Cloud Spanner supports inner, cross, full, left, and right joins. Joins are fast, but since Cloud Spanner distributes data across many splits, any time you can restrict a query to fewer splits, the faster the query will be. Cloud Spanner supports interleaving of your data to define parent-child relationships which allows you to effectively prejoin your data for quicker queries.