Just for disclosure, I used to do a bunch of Rails but I haven’t touched it since the start of covid so it’s applicability to some of what I mentioned was not something I’ve actively built and so I haven’t figured out where all the rough parts are yet because it’s just not a use case of mine these days.
But that second link I mentioned sounds maybe more promising? I initially skimmed it and thought it was there to handle the PostgreSQL to Spanner integration but looking at it a second time it sounds more like native Spanner integration but keeping the otherwise Rails native ActiveRecord experience.
If you’re building against a bunch of PostgreSQL specific functionality then maybe you’re still stuck with the same problem but I don’t think there is a generally speaking more capable publicly available SQL database out there than Spanner than I am aware of is there?
But as a side note if you’re Notion in this situation and not a random small team of a few people I don’t imagine you would have much of a problem reaching out to the GCP team to explain your current set up / requirements, they would be more than happy to give you a custom roadmap to migrate to Spanner, they have entire teams dedicated to exactly those kinds of projects.
By "full", you mean "some"? From [the documentation] on Spanner's PostgreSQL Interface:
> This means that applications written against the PostgreSQL interface can be readily ported to another PostgreSQL environment, obviously without the non-functional benefits, like scalability and availability, that are unique to Cloud Spanner. However, 100% compatibility with PostgreSQL is not the goal.
> The PostgreSQL interface provides a rich subset of the open-source PostgreSQL SQL dialect, including common query syntax, functions, and operators
It seems like existing simple Postgres applications could switch to Spanner, but it does require running a sidecar if your app wants to continue speaking the Postgres protocol on the wire, instead of integrating a Spanner API client.
When it comes to [datatypes], Spanner's PostgreSQL interface is very limited. According to the docs, only these types are supported:
> bool, bytea (byte array), float8 (64-bit IEEE-754 float), int8 (signed 64-bit int), numeric/decimal, timestampz, text.
Notably missing for [my use-case] are UUID, JSON/JSONB, array types like UUID array, and custom enum types. The indexing support is also quite sparse. Full Postgres compatibility, this is not :(
[the documentation]: https://cloud.google.com/spanner/docs/postgresql-interface
[datatypes]: https://cloud.google.com/spanner/docs/reference/postgresql/d...
[my use-case]: https://www.notion.so