Instead of observing all changes in all instances and then filtering them in the observe callback, we could provide already a query to the database to limit documents. For example, {_id: {$gte: 'a', $lt: 'c'} returns only documents where _id starts with a or b.
Instead of observing all changes in all instances and then filtering them in the observe callback, we could provide already a query to the database to limit documents. For example,
{_id: {$gte: 'a', $lt: 'c'}returns only documents where_idstarts withaorb.