"database": "foo", "hosts": null } }, { "id": "where1", "kind": "where", "spec": { "expression": { "root": { "type": "binary", "operator": "and", "left": { "type": "binary", "operator": "and", "left": { "type": "binary", "operator": "==", "left": { "type": "reference", "name": "_measurement", "kind": "tag" }, "right": { "type": "stringLiteral", "value": "cpu" } }, Query represented as DAG in JSON