Bulk import of patients on Amazon

We are using an Amazon Dynamo instance for our fhir records. We need to bring in about 50,000 patients. What is the recommended way of inserting this number of records in a timely manner?

First we tried looping through the db and it works fine but takes a 1 sec per record so this just doesn’t seem like the right way to approach this. We’ve also experimented with Bundles. However there seems to be a limit of around 20 records per bundle.

I’m sure people have imported way more records than this and there is a recommended solution that I’m not aware of. Any input here would be appreciated.

Thank you