Mounting

Mounting is the ability to add datasets and remote databases to a sgr engine without having to actually download or clone them. You can then query these datasets with any PostgreSQL client, with the sgr engine transparently rewriting and forwarding queries to the upstream data source.

Besides querying these "live" sources directly, you can also reference them in Splitfiles or snapshot them with sgr import, creating a new Splitgraph image.

Mounting is powered by PostgreSQL foreign data wrappers and we added some scaffolding to them to make it easy to create foreign tables from the sgr client. sgr also ships with a few open-source foreign data wrappers, letting you query other PostgreSQL/MySQL databases, MongoDB collections or even government open data directly through sgr.

Finally, it's straightforward to write your own foreign data wrapper with Multicorn or integrate existing ones with sgr.