To ensure that all records have a corresponding index entry in the _id index, we can implement the following steps during the extra index check on _id:

When finding a record for a specific _id index key, check that the next record also has the corresponding _id index key entry. Flag this as an error if a match is not found.
Continue moving forward until you find a match.

Note: Limit the search to avoid iterating over a large number of keys, which could impact performance.

Additionally, we need to perform this check for the first record of the collection to ensure comprehensive coverage.