As we noted last week, necessity is one of the six key factors that are driving the adoption of alternative data management technologies identified in our latest long format report, NoSQL, NewSQL and Beyond.
Necessity is particularly relevant when looking at the history of the NoSQL databases. While it is easy for the incumbent database vendor to dismiss the various NoSQL projects as development playthings, it is clear that the vast majority of NoSQL projects were developed by companies and individuals in response to the fact that the existing database products and vendors were not suitable to meet their requirements with regards to the other five factors: scalability, performance, relaxed consistency, agility and intricacy.
The genesis of much – although by no means all – of the momentum behind the NoSQL database movement can be attributed to two research papers: Google’s BigTable: A Distributed Storage System for Structured Data, presented at the Seventh Symposium on Operating System Design and Implementation, in November 2006, and Amazon’s Dynamo: Amazon’s Highly Available Key-Value Store, presented at the 21st ACM Symposium on Operating Systems Principles, in October 2007.
The importance of these two projects is highlighted by The NoSQL Family Tree, a graphic representation of the relationships between (most of) the various major NoSQL projects:
Not only were the existing database products and vendors were not suitable to meet their requirements, but Google and Amazon, as well as the likes of Facebook, LinkedIn, PowerSet and Zvents, could not rely on the incumbent vendors to develop anything suitable, given the vendors’ desire to protect their existing technologies and installed bases.
Werner Vogels, Amazon’s CTO, has explained that as far as Amazon was concerned, the database layer required to support the company’s various Web services was too critical to be trusted to anyone else – Amazon had to develop Dynamo itself.
Vogels also pointed out, however, that this situation is suboptimal. The fact that Facebook, LinkedIn, Google and Amazon have had to develop and support their own database infrastructure is not a healthy sign. In a perfect world, they would all have better things to do than focus on developing and managing database platforms.
That explains why the companies have also all chosen to share their projects. Google and Amazon did so through the publication of research papers, which enabled the likes of Powerset, Facebook, Zvents and Linkedin to create their own implementations.
These implementations were then shared through the publication of source code, which has enabled the likes of Yahoo, Digg and Twitter to collaborate with each other and additional companies on their ongoing development.
Additionally, the NoSQL movement also boasts a significant number of developer-led projects initiated by individuals – in the tradition of open source – to scratch their own technology itches.
Examples include Apache CouchDB, originally created by the now-CTO of Couchbase, Damien Katz, to be an unstructured object store to support an RSS feed aggregator; and Redis, which was created by Salvatore Sanfilippo to support his real-time website analytics service.
We would also note that even some of the major vendor-led projects, such as Couchbase and 10gen, have been heavily influenced by non-vendor experience. 10gen was founded by former Doubleclick executives to create the software they felt was needed at the digital advertising firm, while online gaming firm Zynga was heavily involved in the development of the original Membase Server memcached-based key-value store (now Elastic Couchbase).
In this context it is interesting to note, therefore, that while the majority of NoSQL databases are open source, the NewSQL providers have largely chosen to avoid open source licensing, with VoltDB being the notable exception.
These NewSQL technologies are no less a child of necessity than NoSQL, although it is a vendor’s necessity to fill a gap in the market, rather than a user’s necessity to fill a gap in its own infrastructure. It will be intriguing to see whether the various other NewSQL vendors will turn to open source licensing in order to grow adoption and benefit from collaborative development.
NoSQL, NewSQL and Beyond is available now from both the Information Management and Open Source practices (non-clients can apply for trial access). I will also be presenting the findings at the forthcoming Open Source Business Conference.
The NoSQL EU event in London this week was a great event with interesting perspectives from both vendors – Basho, Neo Technology, 10gen, Riptano – and also users – The Guardian, the BBC, Amazon, Twitter. In particular I was interested in learning from the latter about how and why they ended up using alternatives to the traditional relational database model.
Some of the reasons for using NoSQL have been well-documented: Amazon CTO Werner Vogels talked about how the traditional database offerings were unable to meet the scalability Amazon.com requires. Filling a functionality void also explains why Facebook created Cassandra, Google created BigTable, and Twitter created FlockDB (etc etc). As Werner said, “We couldn’t bet the company on other companies building the answer for us.”
As Werner also explained, however, the motivation for creating Dynamo was also about enabling choice and ensuring that Amazon was not trying to force the relational database to do something it was not designed to do. “Choosing the right tool for the job” was a recurring theme at NoSQL EU.
Given the NoSQL name it is easy to assume that this means that the relational database is by default “the wrong tool”. However, the most important element in that statement is arguably not “tool”, but “job” and The Guardian discussed how it was using non-relational data tools to create new applications that complement its ongoing investment in the Oracle database.
For example, the Guardian’s application to manage the progress of crowdsourcing the investigation of MP’s expenses is based on Redis, while the Zeitgeist trending news application runs on Google’s AppEngine, as did its live poll during the recent leader’s election debate. Datablog, meanwhile, relies on Google Spreadsheets to serve up usable and downloadable data – we’ll ignore for a moment whether Google Spreadsheets is a NoSQL database
Long-term The Guardian is looking towards the adoption of a schema-free database to sit alongside its Oracle database and is investigating CouchDB. The overarching theme, as Matthew Wall and Simon Willison explained, is that the relational database is now just a component in the overall data management story, alongside data caching, data stores, search engines etc.
On the subject of choosing the right tool for the job, Basho’s engineering manager Brian Fink pointed out that using NoSQL technology alongside relational SQL database technology may actually improve the performance of the SQL database since storing data in a relational database that does not need SQL features slows down access to data that does need SQL features.
Another perspective on this came from Werner Vogels who noted that unlike database administrators/ systems architects, users don’t care about where data resides or what model it uses – as long as they get the service they require. Werner explained that the Amazon.com homepage is a combination of 200-300 different services, with multiple data systems. Users do not think about data sources in isolation, they care about the amalgamated service.
This was also a theme that cropped up in the presentation by Enda Farrell, software architect at the BBC, who noted that the BBC’s homepage is a PHP application integrated with multiple data sources at multiple data centers, and also Twitter‘s analytics lead Kevin Weil, who described Twitter’s use of Hadoop, Pig, HBase, Cassandra and FlockDB.
While the company is using HBase for low-latency analytic applications such as people search and moving to Cassandra from MySQL for its online applications, it uses its recently open-sourced FlockDB graph database to serve up data on followers and correlate the intersection of followers to (for example) ensure that Tweets between two people are only sent to the followers of both. (As something of an aside, Twitter is using Hadoop to store the 7TB of of data its generates a day from Tweets, and Pig for non-real time analytics).
Kevin noted that the company is also working with Digg to build real-time analytics for Cassandra and will be releasing the results as open source, and also discussed how Twitter has made use of open source technologies created by others such as Facebook (both Cassandra and the Scribe log data aggregation server.
One of the issues that has arisen from the fact that organizations such as Amazon and Facebook have had to create their own data management technologies is the proliferation of NoSQL databases and a certain amount of wheel re-invention.
Werner explained that SmugMug creator Don Macaskill ended up being a MySQL expert not because he necessarily wanted to be, but because he needed to be because he had to be to keep his applications running.
“He doesn’t want to have to become an expert in Cassandra,” noted Werner. “What he wants is to have someone run it for him and take care of that.” Presumably Riptano, the new Cassandra vendor formed by Jonathan Ellis – project chair for the Cassandra database – will take care of that, but in the meantime Werner raised another long-term alternative.
“We shouldn’t all be doing this,” he said, adding that Dynamo is not as popular within Amazon Web Services as it once was as it is a product, that requires configuration and management, rather than a service, and Amazon employees “have better things to do.”
Which raises the question – don’t Twitter, Facebook, the BBC, the Guardian et al have better things to do than developing and maintaining database architecture? In a perfect world, yes. But in a perfect world they’d all have strongly consistent, scalable distributed database systems/services that are suited to their various applications.
Interestingly, describing S3 as “a better key/value store than Dynamo”, Werner noted that SimpleDB and S3 are “a good start to provide that service”.