讓我想到 cockroachdb 就看到 hackernews 上的 comment1 了

One of the big differences is that Spanner only uses SQL for read-only operations, with a custom API for writes. We use standard SQL for both reads and writes, which means we also work with major ORMs like GORM, SQLAlchemy, and Hibernate (docs should be live today or tomorrow). Spanner's custom write API will make it difficult to work with existing frameworks, or to convert an existing application to Spanner. Cloud Spanner only works on Google Cloud and is a black-box managed service. CockroachDB is open source and can be run on-prem or in any cloud on commodity hardware. (We don't offer CockroachDB as a service yet, but may in the future)

很扯...

• 支援 SQL select/join/subquery/index ...etc
• 不支援 DML (要用它的 client)，猜測是目前只限於做 primary key 相關的 update
• 開一台 0.9 usd/hour，儲存和傳輸另外算錢

每一 instance 的能力 :

each Cloud Spanner node can provide up to 10,000 queries per second (QPS) of reads or 2000 QPS of writes (writing single rows at 1 KB data per row), and 2 TiB storage.

0.9 usd/hour 相當於 aws m4.4xlarge (16 core/64GB ram)