Snapshots

Snapshots are an artifact of calls to pgml.train() that specify the relation_name and y_column_name parameters. See Training Overview for ways to create new snapshots.

Schema

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CREATE TABLE IF NOT EXISTS pgml.snapshots(
	id BIGSERIAL PRIMARY KEY,
	relation_name TEXT NOT NULL,
	y_column_name TEXT[] NOT NULL,
	test_size FLOAT4 NOT NULL,
	test_sampling pgml.sampling NOT NULL,
	status TEXT NOT NULL,
	columns JSONB,
	analysis JSONB,
	created_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT clock_timestamp(),
	updated_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT clock_timestamp()
);

Snapshot Storage

Every snapshot has an accompanying table in the pgml schema. For example, the snapshot with the primary key 42 has all data saved in the pgml.snaphot_42 table.

If the test_sampling was set to random during training, the rows in the table are ordered using ORDER BY RANDOM(), so that future samples can be consistently and efficiently randomized.