http://blogs.enterprisedb.com/2014/09/24/postgres-outperforms-mongodb-and-ushers-in-new-developer-reality/ EDB found that Postgres outperforms MongoDB in selecting, loading and inserting complex document data in key workloads involving 50 million records: Ingestion of high volumes of data was approximately 2.1 times faster in Postgres MongoDB consumed 33% more the disk space Data inserts took almost 3 times longer in MongoDB Data selection took more than 2.5 times longer in MongoDB than in Postgres