I wonder why they charge a minimum of $0.90 per node-hour when they offer VMs for as little as $0.008/hr. This is hugely useful even for single-person startups, so why charge a minimum of ~$8,000 per year?
My intuition, which I hope is wrong, suggests this is a small market.
The ideal market for Spanner seems to be new projects developed by big companies that know that big traffic will arrive on day 1. In other words, Google. Which I guess shouldn't be too surprising...
I'd certainly love to see us get to a world where we can split up a single spanner "install" in an isolated, multitenant manner, but even for a small company, $8k/year is admittedly a small fraction of one engineer. At a company with several, you can share your single Spanner instance just like you would any other database.
Disclosure: I work on Google Cloud (but not Spanner).
This is certainly true, but overlooks the fact that many major products start out as experimental projects, and $8k/year is a significant investment for an experiment.
If there's a reasonable upgrade path from traditional databases like MySQL and Postgres this shouldn't be a big deal, but if the answer is "rewrite your app" it will probably be a friction point for adoption.
Companies with more data than can fit in a single-instance RDBMS system (like >3TB of hot data, more throughput than a single node can handle) but still seeking transactional consistency are a clear use case. Single-person startups could definitely benefit, but it's a less-likely scenario that they would require the level of coverage Spanner provides.
Having your database problem solved however, one less thing to worry about, if you're bigger.