Mongorestore to update records if already exists without --drop

Please vote for this ticket to add an upsert option to mongorestore.

Until that is implemented, we have found a workaround:

1. Dump Collection From Server A ( original )
2. Dump Collection From Server B ( target )
3. Restore With Drop Collection A on Server B 4
4. Restore Without Drop Collection B on Server B

In this case updated document will not overwritten

The first case is true. Mongorestore does not update documents if already exist. It skips those documents when restoring. In your second case, please try using mongoimport with --upsert option. It will merge the records if _id already exists.

Example:

mongoimport --db dbname --collection collname --upsert --file file.json