In-Memory Databases Are Finally Here

In-Memory Databases Are Finally Here

The cost of RAM has declined steadily over the past several decades. I'm talking about RAM, the full name of which is Random Access Memory, not to be confused with Flash Memory or Solid-state drives. RAM is the portion of memory that is most closely connected to a computer's motherboard and CPU. If the CPU can be likened to a muscle, we might say that RAM is like oxygen, or even the blood flow itself. Back in the year 2000, one gigabyte of RAM used to cost over $1,000, but today you can get a 32 GB stick of server-grade RAM for under $389. This represents a price drop of 98.8% when compared on a per-gigabyte basis. Furthermore, the RAM of today comes in larger amounts per chip, and is much faster than the RAM most of us grew up on. This is not your father's RAM.

One major consequence of more powerful RAM becoming less expensive is that the cloud application world is now able to make the leap to in-memory database architectures. SAP is in the news frequently with their HANA In-Memory Computing solution for analyzing big data. Workday is different by design due to its approach to in-memory database usage. All the leading RDBMS vendors (Microsoft, Oracle, and many more) are building in-memory support into their database platforms. And of course all the new cloud-first database platforms (Cassandra, Couchbase, MemcacheDB, etc.) offer in-memory techniques to help achieve high performance.

In various ways these vendors and platforms are essentially leveraging the availability of large amounts of relatively inexpensive RAM to solve a common problem, which is that of breaking through the limits of traditional hard disk drives. Modern motherboards, CPU's, and RAM have seen vast improvements in performance over the past decade while spinning disks have not kept up that pace. Database software makers are tired of waiting for storage technology to catch up. Even solid state drives pale in comparison to RAM when it comes to raw I/O throughput and random reads and writes. Database makers are now simply bypassing the hard disk drive altogether, using specially designed architectures to do it.

Certify is among the ranks of software firms that have seen the vision and benefits of in-memory database architecture and began planning for it long ago. Several of my colleagues here at Certify would testify that for the past several years I have basically worn them out with continuous talk of this exciting new world opening up before us. But it turns out that spinning disks are not the enemy themselves – it is how they have been traditionally used that is the enemy. As a medium for permanent data storage, and when properly configured in RAID arrays, they are marvelous creatures. But the time has now passed for trying to configure that same RAID array of spindles for massive I/O in order to attempt to scale up.

So how does Certify scale so well? The answer is simple: in-memory database concepts are built into the architecture. All system level data is maintained in application server memory, and is kept up to date with real-time caching. All customer metadata and most customer business data is likewise maintained in application server memory, also with real-time caching. The critical aspect of doing this properly lies in the contracts between the database layer and the application layer so that cached data is never stale, but instead is kept up to date in real-time while being distributed horizontally across all application servers. When any system gets this equation right without sacrificing flexibility, amazing possibilities open up in terms of performance and scalability. This is how Certify is able to scale as a true single-instance, multi-tenant cloud application.

But of course there is more to scalability than just raw performance. In a future blog post, I will share a bit about Certify's approach to database sharding. If you have not designed your system to make better use of large amounts of RAM, then get out there and start shopping – the hardware vendors are offering you a 98.8% off coupon!
Alan Neveu

Certify, CTO