Azure Cosmos DB containers are now internally backed by two storage engines—a transactional storage engine and a new analytical storage engine. Both the storage engines are log-structured and write-optimized for blazing fast updates. The transactional storage engine is encoded in row-oriented format for blazing fast transactional reads and queries. The analytical storage engine is encoded in columnar format for fast analytical queries and scans and is fully updatable. The transactional storage engine is backed by local SSDs, and the analytical storage is stored on a cost efficient, off-cluster SSD storage.
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