This time, I wanted to ask the opinion of an ODBMS vendor on the topic of “NoSQL databases”. I therefore asked Robert Charles Greene, V.P. Open Source Operations, at Versant Corporation.
RVZ: Robert, you represent an ODBMS vendor, what is your opinion of the so called “NoSQL databases”? Are object databases “NoSQL” technologies?
Robert Charles Greene:
I find that lots of folks are getting all worked up over the dubbed “No SQL” movement. I guess it`s because one can easily make assumptions and draw a would be obvious analogy to a “No Relational” movement and that would certainly be something to get worked up over.
As the object database guy, I see the core message being conveyed as, “one size does not fit all” when it comes to data management. That`s a far cry from abandoning the SQL approach to data management and in my mind leaves little to defend, though some seem to feel threatened enough by the catch phrase to sound the alarm.
In some sense, this notion that “one size does not fit all” is an important change in attitude, because for many years one size fits all was prevalent. Only as the internet gave way to the masses and large scale concurrency and data generation ushered in a new era has the relational way of doing data management truly begun to break down, opening the door to alternatives.
The “right tool for the job” has once again become a mantra of the software development community and equally important, the mantra of the decision makers in Enterprise I.T. As evidence, one has to look no further than the proliferation of data warehousing solutions outside the realm of relational database technology, ironically, to support the adhoc query and analytics, the founding pillars of the past which brought the relational database to such high esteem. Indeed, necessity may well be the mother of invention, for if not, it would most certainly be the father of adoption. So, if the RDB is no longer the king of query, then really, what is there to get all worked up about if necessity drives adoption in yet even more directions.
So, what is this NoSQL movement all about and does it warrant the public espousal of opinions. Well, as stated above, this is an important change in attitude which will bring valuable choices to our industry making us better equipped to deal with today`s infrastructure challenges, so yes, indeed it is worth discussion.
Michael Stonebreaker decided it was important to comment on this “movement” and gave an interesting NoSQL perspective here (courtesy of ACM).
I largely agree with the technical elements of his perspective, though I would suggest as in the above, the slightly different perspective that the core message is, “one size does not fit all”. I encourage the reader to then keep this in mind as they engage in a broader understanding of what these exciting new technologies provide.
Also, it is worth pointing out, while many of the technologies involved in the NoSQL movement do sacrifice ACID as a means to achieve their end in both performance and scalability, most object databases are ACID compliant and one might argue are the original NoSQL movement.
But lets not digress, as even Michal asserts, the NoSQL movement is not about SQL. So, while object databases are by and large “NoSQL” technologies, they are not a kind of Query-less technology. Indeed, while today`s modern object databases embrace the requirement for distributed parallel query processing, they also hold true to the core tenants of large scale distribution, object clustering and parallel processing all in the context of an ACID compliant transaction. These features surround a robust environment for dealing with arbitrarily complex object models, an area in which many of the NoSQL movement participants fall short.
In summary, the “one size does not fit all” change in attitude is healthy and beneficial for all.
To that end, the object database, a continuing NoSQL movement participant, is one more tool in the developers tool chest, enabling successful implementation of complex software systems of scale.
Cheers,
-Robert
This time, I asked Kaj Arnö (MySQL), what does he think of “NoSQL databases”. Read his reply below.
RVZ
RVZ: What is your opinion of the so called “NoSQL databases”?
Kaj Arnö :
NoSQL is a catchy name, which in char(5) captures a lot of thinking.
To be technical, it’s not merely about removing SQL, but about removing most relational database overhead (where SQL, although dominant, is just an implementation of a query language). And some of that overhead is clearly not necessary all the time. It’s a lot of protocol to implement all aspects of ACID compliance, and it isn’t always needed. Especially in the early days of MySQL, we were accused of cutting corners — for instance through MyISAM not being fully ACID. Still, MyISAM was used a lot, and it still is. Coming back to the NoSQL debate, I would say that the MySQL idea of cutting overhead is gaining traction in other tools, which may choose to cut larger chunks or different corners. That’s a healthy development, since the
shortcuts to be taken depend on the class of application.
Kaj
Kaj joined MySQL in 2001, after 14 years as an entrepreneur. Serving as VP Services, VP Engineering and other exec roles at MySQL, he has been the VP in charge of MySQL Community Relations since 2005, continuing that position in Sun Microsystems. A native of Finland, Kaj lives in Munich since 2006. He devotes his free time to launching Runnism, the Religion of Running.
Moreover, there has been a recent post by professor Michael Stonebraker related to the topic “No SQL” databases and their performance with respect to classical relational database systems.
In his post, titled “The “NoSQL” Discussion has Nothing to Do With SQL”, Prof. Stonebraker argues that “blinding performance depends on removing overhead. Such overhead has nothing to do with SQL, but instead revolves around traditional implementations of ACID transactions, multi-threading, and disk management. To go wildly faster, one must remove all four sources of overhead, discussed above. This is possible in either a SQL context or some other context.”
The Link to Stonebraker`s Blog (courtesy of ACM).
I also published an article of David Chappell: “Introducing Windows Azure”. The paper describes Microsoft`s Windows Azure. In fact, the “Tables” abstraction in Windows Azure is similar to some “nosql databases”. You can download the paper (.PDF) here.
Patrick Linskey on “cloud store”
I have asked Patrick Linskey on his opinion on the new wave of “data stores”, such as “document stores”, and “nosql databases”.
You can read the interview below.
Roberto V. Zicari
RVZ:
Patrick, there has been recently a proliferation of “data stores”, such as “document stores”, and “nosql databases”.
Systems such as CouchDB, MongoDB, SimpleDB, Voldemort, Scalaris, etc. provide less functionality than OODBs but a distributed “object” cache over multiple machines.
See for example: wiki/Nosql,
wiki/wiki/Document-oriented_database,
and the article: NoSQL: Distributed and Scalable Non-Relational Database Systems.
What do you think about it?
Patrick Linskey:
I think that the “cloud store” subset of them are pretty fascinating. Of course, as with so much in the software industry, much of what these projects are doing is old hat. But I think that they’re relatively unique in
(a) successfully combining compelling complementary sets of features together,
(b) building solutions for known and needed use cases, rather than the more ivory-tower approach that’s all too typical of commercial products, and
(c) designing and implementing in a manner oriented to cloud-scale deployment from the very start (i.e., lots of data; geographically diverse data centers; high load requirements).
I expect that all the successful cloud store projects will end up with support for declarative queries and declarative secondary keys. I really don’t like the “nosql” term — I think that Geir Magnusson does a good job of pointing out that the cloud store community is more focused on “alongside SQL”. That is, there’s nothing wrong with using a relational database in the situations where it’s the best tool for the job. The new cloud stores are focused on filling the gaps where most RDB alternatives fall flat.
The way they do it, of course, is by getting rid of problematic features. I think that some of the hype has mis-identified these
problematic features, though. Declarative queries (and full metamodel introspection) and secondary key support are really cool and critical features of all the popular relational databases. The cloud store users out there are doing a lot of extra work because of the absence of these features — essentially re-implementing them in their application code. Imagine how horrible it’d be if you told a modern DB team that they needed to change their app to tune their database!
So: what are cloud stores omitting that enable them to scale so well?
There are two answers:
– cloud stores are intentionally designed to scale. No* single points of failure, built-in support for consensus-based decisions, partitioning / replication as basic primitives, etc. Taking a codebase designed for a single server and evolving it to a multi-server solution is difficult, since single-machine assumptions often calcify into the implementation.
– more importantly, cloud stores aren’t fully ACID, in the traditional sense of the term. By re-casting the data storage problem in more amenable terms (eventual consistency, atomic operations (but not atomic sequences of operations), etc.), the different products can make acceptable trade-offs that traditional single-server ACID stores are simply designed to forbid.
I’d love to see a comparison of established products like TeraData and Coherence to the various new cloud store projects. TeraData, in particular, does an interesting job of re-using the familiar SQL/JDBC model while making a lot of the same compromises and architectural decisions as the new set of cloud stores.
(I’m less interested in — and educated about — the single-server nosql projects. These days, I believe that all single-server databases are basically equivalent, since if you are using a single server, your application is sufficiently simple that you should be able to be successful with any of a number of data storage models.)
-Patrick
Patrick Linskey has been involved in object/relational mapping and databases for the last decade. As the founder and CTO of SolarMetric, Patrick drove the technical direction of the company and oversaw the development of Kodo, through its acquisition by BEA. At BEA, Patrick led the EJB team in designing and implementing the WebLogic Server EJB 3.0 solution, and represented BEA on the JDO and EJB3 expert groups. He is a contributor to the Apache OpenJPA project.
Since leaving Oracle, Patrick has worked on a number of projects, ranging from traditional three-tier web and mobile applications to C# peer – to – peer client applications with custom-designed distributed storage solutions.
I am happy to inform you that the 3rd International Conference on Objects and Databases (ICOODB), will take place on September 28-30, 2010, at the Goethe University in Frankfurt/Main, Germany.
The previous edition of ICOODB took place this year at ETH in Zurich.
RVZ
There is a growing interest in our community in having resources published in ODBMS.ORG, which compare & contrast ODBMS with other “data stores”, such as “document stores”, and “nosql databases”.
Systems such as CouchDB, MongoDB, SimpleDB, Voldemort, Scalaris, etc. provide less functionality than OODBs but a distributed “object” cache over multiple machines.
I plan to add a number of new resources on that in the next months to come.
RVZ
Last month, September 2009, was the best month ever for ODBMS.ORG!
We had 40,370 visitors…
Thank you.
RZ
I am glad to inform you that ODBMS.ORG is listed under the IBM Academic Initiative, in their official Courseware: A Catalog of Educational Materials:
ODBMS.org
“The Object Database Management Systems portal provides the most up-to-date collection of free materials on object database technology on the Internet.”
Here is the link: IBM Academic Initiative – Courseware.
RVZ
I have published several new resources in ODBMS.ORG:
– A new User Report, (number 32/09), by Dr. Andreas Geppert at Credit Suisse, Switzerland.
Andreas Geppert is a Platform Architect. Gepperts tell us that the strategy of his bank is to buy IT infrastructures whenever possible, and avoid developing them in-house. When asked if they had an “impedance mismatch” problem in the bank, Geppert replied: “We certainly have an impedance mismatch problem, in particular as we are increasingly developing new applications in Java accessing relational databases such as Oracle and DB2.”
You can read the full report in the Object Databases – User Reports Section.
– A Link to download Databeans.
Databeans is an object oriented persistence framework for Java, available under GPL. The link is available here.
-A Link to download ConceptBase.
ConceptBase is a multi-user deductive and object-oriented database system for meta modeling and method engineering, developed by Tilburg University. It is freely available under a FreeBSD-style license. The link is available here.
– Databeans Tutorial for Java version 2.0.
You can download the tutorial (PDF) in the Object Databases – Tutorials Section.
– Slides of a course based on ConceptBase, developed by Tilburg University.
The slides are under a permissive Creative Commons license, and are available here.
I would also like to welcome a new Expert Manfred Jeusfeld, who has just joined the ODBMS.ORG`s panel of Experts.
Hope you`ll find the resources useful. And as always, all resources in ODBMS.ORG are freely accessible!
RVZ
InterSystems supports ODBMS.ORG
I am glad to report that InterSystems is now supporting ODBMS.ORG
InterSystems is the provider of the object database Caché. If you are interested, you can evaluate Caché
I`d like to mention that I have published a complete new updated version (2009) of the ETH Zurich ODBMS Lecture Series on ODBMS.ORG (PDF).
This is by far the most up-to-date and comprehensive lecture series on object databases, developed by Michael Grossniklaus, and Moira Norrie at the renowned Swiss Federal Institute of Technology (ETH) Zurich.
For the 2009 version of ETH Zurich’s lecture on Object-oriented databases a number of additions and updates have been made:
– New lecture providing a Versant tutorial
– New lecture discussing different OODBMS architectures
– Updated lectures on db4objects incorporating new features such as transparent persistence and activation.
– Updated lectures on the OM model of data, OML and OMS Avon
– Many corrections of errata throughout the whole course.
RVZ
