This is also the pattern targeted by PowerSync (disclosure: co-founder) — selectively syncing scoped data for the user from Postgres to their own client SQLite database. Sync Rules are used to define which data is synced to which users: https://docs.powersync.co/usage/sync-rules
This is the fifth comment I’ve counted plugging Powersync in this thread. I guess it’s the nature of the startup hustle game but this level of promotion in someone else’s Show HN thread feels a little distasteful. Maybe you could post your own Show HN?
I hear you, thanks for sharing your thoughts and for the suggestion. Noted. I didn’t mean to just plug — I thought I was contributing to the discussion and that some people may find another implementation relevant/interesting.
ElectricSQL stores additional data in the source PostgreSQL database, while PowerSync stores this in a separate data store in its sync service. Because of this, ElectricSQL requires schema changes and has some schema restrictions on the source database.
ElectricSQL uses CRDTs for merging changes, via the Electric backend. PowerSync records changes per transaction on the client and lets the developer write changes to their database, which can be customized with custom write logic, validations, and access control.
ElectricSQL uses “shapes” (currently a WIP feature) defined on the client to partition data, while PowerSync uses server-side “sync rules”. The sync rules approach allows data to be transformed and filtered using basic SQL queries, which we expect to scale well (benchmarks pending). PowerSync guarantees consistency over all synced data, while it appears like ElectricSQL only guarantees consistency within each shape*. PowerSync also automatically adds and removes sync buckets when changes are made to either the sync rules or data, while ElectricSQL likely* requires you to subscribe and remove shapes yourself.
ElectricSQL streams schema migrations to the client. Part of the PowerSync design philosophy is that each client version should have a static schema. PowerSync syncs “schemaless” data, then applies a client-side schema (typically a mirror of the Postgres schema, but can be customized) on top of that using SQLite views.
*We’re making some assumptions about ElectricSQL where the documentation is not clear - please correct us if we got something wrong.
