All of the following three share something in common: 1) Microsoft Azure DocumentDB 2) Google Cloud Spanner 3) Amazon Web Services DynamoDB Total cloud-vendor

All of the following three share something in common: 1) Microsoft Azure DocumentDB 2) Google Cloud Spanner 3) Amazon Web Services DynamoDB Total cloud-vendor lock-in. It's clear why the clouds want users investing in these difficult-to-migrate-from solutions...