sgr checkout

sgr checkout [OPTIONS] IMAGE_SPEC

Check out a Splitgraph image into a Postgres schema.

This downloads the required physical objects and materializes all tables, unless -l or --layered is passed, in which case the objects are downloaded and a foreign data wrapper is set up on the engine to satisfy read-only queries by combining results from each table's fragments.

Tables checked out in this way are still presented as normal Postgres tables and can queried in the same way. Since the tables aren't materialized, layered querying is faster to set up, but since each query now results in a subquery to each object comprising the table, actual query execution is slower than to materialized Postgres tables.

Layered querying is only supported for read-only queries.

Image spec must be of the format [NAMESPACE/]REPOSITORY[:HASH_OR_TAG]. Note that currently, the schema that the image is checked out into has to have the same name as the repository. If no image hash or tag is passed, "HEAD" is assumed.

If -u or --uncheckout is passed, this instead deletes the checked out schema (assuming there are no pending changes) and removes the HEAD pointer.

If --force isn't passed and the schema has pending changes, this will fail.

Options

  • -f, --force: Discard all pending changes to the schema
  • -u, --uncheckout: Delete the checked out copy instead
  • -l, --layered: Don't materialize the tables, use layered querying instead.