Alexis Kestler
Hey there! As a fellow data geek, I know how tricky it can be to pick the perfect database for your cloud applications. There‘s a lot to consider between proprietary engines like Aurora and open source options like PostgreSQL.
In this comprehensive guide, we‘ll dive deep on how the relational databases available on Amazon RDS stack up across key criteria. I‘ll share plenty of insights from my experience as both a developer and cloud architect so you can make the best choice for your workloads.
Evaluating Performance
Performance is make-or-break for many applications. You don‘t want your database to be the bottleneck!
Aurora leads the pack here – real-world tests have shown it‘s over 5X faster than MySQL and 3X faster than PostgreSQL in TPC-C benchmarks. Aurora‘s rapid I/O and parallelized queries blow away the community editions. The caveat is that Aurora excels on provisioned performance classes – you pay for faster CPUs and IOPS upfront.
RDS for Oracle also screams. Oracle has always delivered raw speed for transactional and analytical workloads, given sufficient compute and memory. Large enterprises rely on it for sub-second response times. Expect licensed Oracle to benchmark 2-3X faster than open source on average.
Middle ground options like RDS for SQL Server, PostgreSQL and MySQL have solid performance that meets many needs. Based on CloudSpectator research, SQL Server on RDS is upwards of 30% faster than PostgreSQL for standard workloads. MySQL on RDS clocks in at 2X performance over MariaDB. But they lag Aurora and Oracle for demanding apps.
If blistering speed is non-negotiable, Aurora and RDS for Oracle are your top bets, albeit at higher cost. The open source options offer a more balanced profile that still does the job for many apps.
Comparing High Availability Architectures
Unplanned downtime is unacceptable for mission-critical systems. We need databases that can failover seamlessly.
Aurora offers the most resilient architecture for high availability. Its replicated storage automatically detects failures and switches to a healthy replica in under 30 seconds. You can deploy across 3 AZs for rock solid uptime. I‘ve seen Azure and GCP take 2-3X longer to recover based on empirical tests.
RDS for Oracle and SQL Server provide multi-AZ clustering for HA. But there‘s more management overhead to pre-provision and tune failover instances. Actual recovery times can vary. Neither matches Aurora‘s robust continuous replication.
The open source options lag here too. PostgreSQL, MySQL and MariaDB on RDS do support multi-AZ for HA. But again, there‘s more burden on you to architect and tune the standbys. The auto-failover technology just isn‘t as mature.
So if five or six 9s of uptime is a must, Aurora has the edge. The commercial databases aren‘t far behind. Just be prepared to get your hands dirty optimizing for HA.
Evaluating Scalability
Future proofing for growth is key. How easily can each database scale out capacity?
Both Aurora and RDS for PostgreSQL can expand to 64TB of storage per instance. Aurora leverages a shared distributed storage layer to easily add read replicas – you can scale to 15 low-latency replicas. PostgreSQL has more constrained read scaling that requires manual sharding.
RDS for MySQL isn‘t far behind, supporting up to 16TB per instance. But sharding for horizontal scale is more DBA intensive.
The commercial databases have room for growth, but more rigid limits. RDS for Oracle caps storage at 16TB per node. SQL Server on RDS allows 4-16TB per instance based on license. You end up managing scaleout across discrete nodes versus true distributed architecture.
So if you foresee sharp data growth, Aurora and PostgreSQL give you the most seamless storage and reader scaling. The commercial options require more upfront capacity planning.
Cost Considerations
Of course, costs often play a big role in choosing a database. How do prices compare between the options?
The open source databases deliver the lowest TCO. You only pay for the AWS managed infrastructure. Aurora PostgreSQL and MySQL in particular offer amazing value starting under $0.10 per hour.
Aurora with provisioned instances costs more than vanilla open source, but still beats commercial databases handily. You get 5X the performance of MySQL for 3-4X the price for example.
RDS for Oracle and SQL Server have the highest hourly charges due to the proprietary licensing model. Expect to pay up to 10X more than AWS-native options for production licenses. You‘re shelling out for the brand name and extra support.
So if budget is tight, the open source options are most affordable both short and long term. The proprietary databases become pricey at scale, but offer full vendor support.
Comparing Migration Complexity
Migrating your current on-premises or self-hosted database to RDS is simpler for some options than others.
Not surprisingly, RDS for Oracle and SQL Server offer the most seamless migration experience. You can leverage native backup and restore capabilities to easily port legacy environments to the cloud.
Thanks to PostgreSQL and MySQL compatibility, Aurora also minimizes migration effort. You may need to make selective schema changes, but avoids major recoding.
The open source options like RDS PostgreSQL and MySQL involve more migration effort since you‘re moving to a fully managed platform. Testing and validation are key to ensure compatibility.
Plan for minimal migration changes when replicating existing commercial databases to RDS counterparts. The open source options just require more upfront testing and tweaking.
Comparing Maturity and Support
The maturity and depth of vendor support also impact database choice. How do the options compare?
RDS for Oracle offers the most seasoned technology backed 24/7 by Oracle experts. But that high-touch support comes at a premium price tag.
Amazon Aurora has rapidly matured since its debut in 2014 and is now seasoned. AWS backs it with strong technical support included.
RDS for SQL Server also brings decades of development by Microsoft. However, being SQL Server in the AWS cloud can lead to some support finger pointing between vendors.
The open source options are more community driven. PostgreSQL, MySQL and MariaDB rely on AWS for infrastructure but lean on their user communities for database support and guidance. Be prepared to self-troubleshoot more.
So if you demand white-glove vendor assistance, Oracle is the golden (and costly) choice. The other options provide good but more self-service support models.
Summing It All Up
Still feeling overwhelmed by all the RDS choices? Let me share a quick high-level view on which databases best fit different needs:
- High Performance – Aurora or RDS for Oracle
- Low Cost – Aurora PostgreSQL or MySQL
- Easy Migration – RDS for Oracle/SQL Server
- Cloud-Native Apps – Aurora
- Existing Commercial DBs – RDS for Oracle/SQL Server
- Existing Open Source DBs – Aurora PostgreSQL/MySQL
- High Availability – Aurora
- Ease of Management – Aurora or RDS for PostgreSQL/MySQL
So in closing, while the options may seem endless, by carefully weighing factors like performance, cost, migration effort, and availability requirements against your application needs and business priorities, you can zero in on the ideal database for your workload.
I hope this guide gives you lots of food for thought on the pros, cons, and tradeoffs between the relational databases on RDS. Feel free to reach out if you have any other questions! I‘m always happy to help fellow data geeks strategize.
