queryDocIds abstract method
Returns the ids of the live documents in table that satisfy spec, in
the spec's total order — (order-by value, document id) — windowed by its
limit and cursor.
A document is live when its existence register (the separator-free key) is live. Predicates evaluate against the resolved value of a field row (a counter's total, a set's membership), so a typed state stored at rest matches the same way on every engine. The comparison order across value kinds is fixed: missing/null, then numbers, then text (non-scalar values compare as their JSON encoding) — every engine must produce the same order, so keyset pages line up across engines and devices.
Implementation
Future<List<QueryRow>> queryDocIds(String table, QuerySpec spec);