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Comment by the_duke | Hacker News Reader

> the PostgreSQL interface implements a core subset of PostgreSQL data types and DDL syntax.

> Familiarity and portability are the goals, not 100% compatibility

So, is there a compatibility matrix?

In general I see this as a good thing. It allows using Spanner without requiring a big rewrite should one want to migrate away from GC. Or using Spanner as a secondary data warehouse with the same queries.

But both of those do require a high level of conformance.

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This page describes what is or isn't supported.

https://cloud.google.com/spanner/docs/postgresql/overview

Notably missing: JSON(B), triggers, sequences/serials, arrays, custom functions.

and I'm out

Lack of JSON(B) is a complete no-go for me

jsonb has become the crutch on which I build everything. And I'm not going back.

Same. PG jsonb is so fantastic that it’s closer to exoskeleton than a crutch.

What do you use JSONB columns for? The only use case that comes immediately to mind is stuff like settings or config blobs for individual entities

I run a multi-tenant SaaS where every tenant can define custom properties on every entity. PG allows us to dump everything into a single jsonb column, and still have superb performance for filtering / analytics / searching etc. The backend codebase remains mostly agnostic to the data shape, and we rarely have to change the database during new releases.

Postgres jsonb + redis_fdw = you can JOIN your structured Postgres data against your unstructured app-layer Redis data. Not a good idea to write any code that does this—just move the Redis data into the DB, for crying out loud—but for BI use-cases where you’re writing one-off SQL queries and you need presentation-layer data that lives in Redis, it’s perfect.

PostgreSQL json functions allow me to dispense with the ORM. Just send and receive JSON (for regular table field types, note, not jsonb).

You know it’s funny because I’m looking into using the JSON type for spanner. Is that comparable to JSONB

Definitely seems like a work in progress, which I suppose is why it's marked pre-GA.

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