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Cloud database comparison: AWS, Microsoft, Google and Oracle

IT expert Chris Foot evaluates the leading cloud databases from AWS, Google, Microsoft and Oracle based on their product offerings and migration capabilities.

The database product landscape no longer consists of a handful of traditional database management system offerings. The database-as-a-service market has exploded with dozens of cloud-based products that range from purpose-built DBMS platforms that focus on meeting a unique set of requirements to general-purpose offerings that have a much wider scope of application.

In order to select the appropriate DBaaS vendor, database professionals must create and execute a well-thought-out cloud database comparison for each of the competing offerings.  

Two of the high-level evaluation criteria IT professionals often use for a cloud database comparison are the breadth of product offerings and migration mechanisms. Based on those criteria, here's an assessment of four of the top DBaaS vendors: Amazon, Microsoft, Google and Oracle.

Breadth of product offerings

Not only do administrators need to understand the basics of the DBaaS product, they also must learn the intricacies of the cloud database vendor's underlying architecture. Using the same vendor for multiple DBaaS products allows administrators to use their existing skills and it simplifies communications between the database-driven applications. Here's how the top DBaaS vendors' offerings compare.

Amazon. Amazon currently leads all competitors in its breadth of DBaaS offerings. Aurora, Amazon's general-purpose relational DBMS, is self-healing and scales storage from 10 GB to 64 TB. Amazon's petabyte-scale data warehouse platform, Redshift, automates warehouse management tasks and uses machine learning to generate insights.

Its in-house, NoSQL offerings include a MongoDB-compatible database called DocumentDB, Neptune for graph applications, DynamoDB for key-value and document, ElastiCache for in- deployments and Timestream for time series data. Amazon's Relational Database Service product suite provides consumers with five DBaaS platforms that include SQL Server, Oracle, MariaDB, MySQL and PostgreSQL.

Microsoft. Coming in second to Amazon is Microsoft, which continues to expand its DBaaS product portfolio and capabilities. Microsoft's relational products include its flagship DBaaS platform, Azure SQL Database, and the SQL Data Warehouse for big data applications.

Microsoft recently increased its 4 TB limit on Azure SQL database sizes to 100 TB with the release of Azure SQL Database Hyperscale. Microsoft also offers a very capable multimodel NoSQL database called Cosmos DB, Azure Table storage for applications requiring a key-value DBMS and Azure Cache for in- Redis. Its open source relational offerings include MySQL, PostgreSQL and MariaDB.

Google. Although a bit of an underdog in the enterprise, Google's growing suite of DBaaS products highlights its keen interest in enterprise business services. The vendor's offerings include a globally consistent relational database called Cloud Spanner and Cloud SQL, which is compatible with MySQL, PostgreSQL and SQL Server.

Google's NoSQL products include Google Cloud Bigtable for large-scale workloads, Cloud Firestore for document storage and Firebase Realtime Database for real-time data synchronization. Firebase uses JSON as the storage model.

Oracle. Based on the vendor's comprehensive marketing efforts, it's obvious that Oracle's main focus is to promote its self-driving Oracle Autonomous Database and Autonomous Data Warehouse DBaaS platforms. Oracle says its Autonomous Database offering can do much of the database configuration, tuning, patching and update work usually done by database administrators.

The vendor's DBaaS product line also includes MySQL, its open source relational database. There's also its multimodel NoSQL platform called Oracle NoSQL, Big Data Cloud Service for large scale NoSQL analytics applications and Oracle Exadata Cloud Service -- which is based on its highly engineered Oracle Exadata appliance.

Migration and conversion capabilities

The second core evaluation point for a cloud database comparison is the mechanisms the vendor offers to migrate and convert enterprises' on-premises databases to its platform. Some of the top cloud database competitors thrive in this while others lag.

Amazon. When we compare the leading DBaaS vendors, Amazon's migration and conversion offerings dominate all other competitors. The AWS Database Migration Service is a comprehensive replication utility that allows you to initially seed your DBaaS platform with data and then keep it in sync with your source system. In addition to providing replication between homogenous sources and targets, the product also allows administrators to set up replication between a wide variety of heterogeneous platforms.

Amazon also provides the AWS Schema Conversion Tool, which helps you to convert the source database schema -- including views, stored procedures and functions -- to its Amazon counterpart. The product also allows you to scan application code for embedded SQL statements and converts them to access the database product. 

Google lags behind Microsoft and Amazon in cloud database migration and conversion tool sets.

Microsoft. Although its initial tool sets focused on migrating on-premises SQL Server to Azure SQL Database, Microsoft has been ramping up its efforts to provide utilities that help customers migrate non-Microsoft databases to its DBaaS products.

The vendor recently announced that the Azure Database Migration Service will allow administrators to migrate data from Oracle to Azure SQL Database and Azure Database for PostgreSQL; from MongoDB to Cosmos DB; and from on-premises MySQL and PostgreSQL, and Amazon RDS, to Microsoft's Azure database counterparts. The utility performs the initial load and synchronizes the data until you perform the production cutover.

Google. Google lags behind Microsoft and Amazon in cloud database migration and conversion tool sets. For MySQL and PostgreSQL, the vendor relies on the database's inherent replication features for homogenous migrations. For heterogenous database conversions, Google recommends using its on-premises database tools to create flat-file output. Google's marketing material recommends that customers use its partners that have cloud migration and database conversion experience.

Oracle. In a cloud database comparison of migration mechanisms, Oracle doesn't fare as well as the other DBaaS vendors. Although Oracle recommends numerous methods to convert its own on-premises databases to the Oracle Cloud, the vendor provides no utilities to perform heterogenous database migrations. Oracle relies on its database's inherent data transfer mechanisms for cloud migrations.

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