RDF and graphs
Analysis of data management technology optimized for RDF-formatted and/or graph data.
Toward a NoSQL taxonomy
I talked Friday with Dwight Merriman, founder of 10gen (the MongoDB company). He more or less convinced me of his definition of NoSQL systems, which in my adaptation goes:
NoSQL = HVSP (High Volume Simple Processing) without joins or explicit transactions
Within that realm, Dwight offered a two-part taxonomy of NoSQL systems, according to their data model and replication/sharding strategy. I’d be happier, however, with at least three parts to the taxonomy:
- How data looks logically on a single node
- How data is stored physically on a single node
- How data is distributed, replicated, and reconciled across multiple nodes, and whether applications have to be aware of how the data is partitioned among nodes/shards. Read more
| Categories: Cassandra, Data models and architecture, NoSQL, Parallelization, RDF and graphs, Structured documents, Theory and architecture | 4 Comments |
Some NoSQL links
I plan to post a few things soon about MongoDB, Cassandra, and NoSQL in general. So I’m poking around a bit reading stuff on the subjects. Here are some links I found.
- A little over a year ago, Julian Browne put up a great post on Eric Brewer’s CAP conjecture/theorem, which provides much of the impetus to relax the traditional requirement for atomicity/consistency.
- Even more directly inspirational to NoSQL technology development were two seminal papers: Google’s on BigTable and Amazon’s on Dynamo. (That said, I’m having trouble getting myself to actually read them from start to finish, especially since they’ve been superseded by subsequent technology development.)
- 10gen (the MongoDB guys) hosted a NoSQL conference yesterday. Much blogging has ensued. The best post I’ve seen so far was by Adam Marcus. I find the graph database notes near the bottom particularly interesting.
- Mark Callaghan hit back against the NoSQL movement hype, and in particular against the MySQL/memcached is passe‘ meme. On the other hand, he also bemoaned many failings of MySQL. On the third hand, he praised or at least expressed hope for a variety of MySQL-related technologies, including Tokutek’s TokuDB and Continuent’s Tungsten.
- In connection with that debate, Mark Rendle offered a funny rant, mainly pro-NoSQL, in the style of a Socratic dialogue.
- John Quinn of Digg recently described Digg’s move from MySQL to Cassandra, and outlined a lot of features Digg was adding to Cassandra, all of which it is open-sourcing.
- The NoSQL guys maintain their own long list of NoSQL-related links.
| Categories: Amazon and its cloud, Cassandra, Continuent, Google, MySQL, NoSQL, Open source, RDF and graphs, Tokutek | 5 Comments |
Aster Data nCluster 4.5
Like Vertica, Netezza, and Teradata, Aster is using this week to pre-announce a forthcoming product release, Aster Data nCluster 4.5. Aster is really hanging its identity on “Big Data Analytics” or some variant of that concept, and so the two major named parts of Aster nCluster 4.5 are:
- Aster Data Analytic Foundation, a set of analytic packages prebuilt in Aster’s SQL-MapReduce
- Aster Data Developer Express, an Eclipse-based IDE (Integrated Development Environment) for developing and testing applications built on Aster nCluster, Aster SQL-MapReduce, and Aster Data Analytic Foundation
And in other Aster news:
- Along with the development GUI in Aster nCluster 4.5, there is also a new administrative GUI.
- Aster has certified that nCluster works with Fusion I/O boards, because at least one retail industry prospect cares. However, that in no way means that arm’s-length Fusion I/O certification is Aster’s ultimate solid-state memory strategy.
- I had the wrong impression about how far Aster/SAS integration has gotten. So far, it’s just at the connector level.
Aster Data Developer Express evidently does some cool stuff, like providing some sort of parallelism testing right on your desktop. It also generates lots of stub code, saving humans from the tedium of doing that. Useful, obviously.
But mainly, I want to write about the analytic packages. Read more
| Categories: Analytic technologies, Aster Data, Data warehousing, Investment research and trading, RDF and graphs, SAS Institute, Teradata | 1 Comment |
Open issues in database and analytic technology
The last part of my New England Database Summit talk was on open issues in database and analytic technology. This was closely intertwined with the previous section, and also relied on a lot that I’ve posted here. So I’ll just put up a few notes on that part, with lots of linkage to prior discussion of the same points. Read more
Webinar on MapReduce for complex analytics (Thursday, December 3, 10 am and 2 pm Eastern)
The second in my two-webinar series for Aster Data will occur tomorrow, twice (both live), at 10 am and 2 pm Eastern time. The other presenters will be Jonathan Goldman, who was Principal Scientist at LinkedIn but now has joined Aster himself, and Steve Wooledge of Aster (playing host). Key links are:
- Registration for tomorrow’s webinars
- Replay of the first webinar
- My slides from the first webinar
The main subjects of the webinar will be:
- Some review of material from the first webinar (all three presenters)
- Discussion of how MapReduce can help with three kinds of analytics:
- Pattern matching (Jonathan will give detail)
- Number-crunching (I’ll cover that, and it will be short)
- Graph analytics (I haven’t written the slides yet, but my starting point will be some of the relationship analytics ideas we discussed in August)
Arguably, aspects of data transformation fit into each of those three categories, which may help explain why data transformation has been so prominent among the early applications of MapReduce.
As you can see from Aster’s title for the webinar (which they picked while I was on vacation), at least their portion will be focused on customer analytics, e.g. web analytics.
| Categories: Analytic technologies, Aster Data, Data integration and middleware, EAI, EII, ETL, ELT, ETLT, MapReduce, RDF and graphs, Web analytics | 2 Comments |
Social network analysis, aka relationship analytics
A number of applications lend themselves to graph-oriented analytics, including:
- Finding bad guys (national intelligence)
- Finding bad guys (anti-fraud)
- Data mining the social graph (e.g., for advertising optimization on social networks, or to identify influencers)
There are plenty more graph-oriented applications, of course, such as the identification of biochemical pathways. But I want to focus for now on ones like those on my list. My key points are:
- There are Big Data problems that lend themselves to graphical data models.
- So far as I can tell, the database management community isn’t doing enough to address them. (If I’m wrong about that, please tell me. I plan to arrive in Lyon for VLDB/XLDB Wednesday of next week, and of course I can always be reached by email.)
Here’s what I mean. Read more
| Categories: Analytic technologies, Cogito and 7 Degrees, Data models and architecture, Data types, RDF and graphs, Theory and architecture | 15 Comments |
Cloudera presents the MapReduce bull case
Monday was fire-drill day regarding MapReduce vs. MPP relational DBMS. The upshot was that I was quoted in Computerworld and paraphrased in GigaOm as being a little more negative on MapReduce than I really am, in line with my comment
Frankly, my views on MapReduce are more balanced than [my] weary negativity would seem to imply.
Tuesday afternoon the dial turned a couple notches more positive yet, when I talked with Michael Olson and Jeff Hammerbacher of Cloudera. Cloudera is a new company, built around the open source MapReduce implementation Hadoop. So far Cloudera gives away its Hadoop distribution, without charging for any sort of maintenance or subscription, and just gets revenue from professional services. Presumably, Cloudera plans for this business model to change down the road.
Much of our discussion revolved around Facebook, where Jeff directed a huge and diverse Hadoop effort. Apparently, Hadoop played much of the role of an enterprise data warehouse at Facebook — at least for clickstream/network data — including:
- 2 1/2 petabytes of data managed via Hadoop
- 10 terabytes/day of data ingested via Hadoop (Edit: Some of these metrics have been updated in a subsequent post about Facebook.)
- Ad targeting queries run every 15 minutes in Hadoop
- Dashboard roll-up queries run every hour in Hadoop
- Ad-hoc research/analytic Hadoop queries run whenever
- Anti-fraud analysis done in Hadoop
- Text mining (e.g., of things written on people’s “walls”) done in Hadoop
- 100s or 1000s of simultaneous Hadoop queries
- JSON-based social network analysis in Hadoop
Some Facebook data, however, was put into an Oracle RAC cluster for business intelligence. And Jeff does concede that query execution is slower in Hadoop than in a relational DBMS. Hadoop was also used to build the index for Facebook’s custom text search engine.
Jeff’s reasons for liking Hadoop over relational DBMS at Facebook included: Read more
Oracle spotlights its datatype support
Oracle put out a flurry of press releases today in conjunction with Oracle OpenWorld. One, which was simply positioned as a report on some “mission-critical” customer apps, caught my eye because all four detailed examples involved nonstandard datatypes:
- Two Oracle Spatial
- One “semantic,” which in Oracle lingo seems to mean — you guessed it — RDF
- One DICOM, which seems to be a medical imaging datatype.
| Categories: Data types, GIS and geospatial, Oracle, RDF and graphs | 3 Comments |
Known applications of MapReduce
Most of the actual MapReduce applications I’ve heard of fall into a few areas:
- Text tokenization, indexing, and search
- Creation of other kinds of data structures (e.g., graphs)
- Data mining and machine learning
That covers all MapReduce apps I recall hearing about via commercial companies and users, and also includes most of what’s in the two big sources I found online. Read more
| Categories: MapReduce, RDF and graphs, Text | 13 Comments |
Mike Stonebraker’s DBMS taxonomy
In a response to my recent five-part series on DBMS diversity, Mike Stonebraker has proposed his own taxonomy of data management technologies over on Vertica’s Database Column blog.
- OLTP DBMSs focused on fast, reliable transaction processing
- Analytic/Data Warehouse DBMSs focused on efficient load and ad-hoc query performance
- Science DBMSs — after all MatLab does not scale to disk-sized arrays
- RDF stores focused on efficiently storing semi-structured data in this format
- XML stores focused on semi-structured data in this format
- Search engines — the big players all use proprietary engines in this area
- Stream Processing Engines focused on real-time StreamSQL
- “Lean and Mean,” less-than-a-database engines focused on doing a small number of things very well (embedded databases are probably in this category)
- MapReduce and Hadoop — after all Google has enough “throw weight” to define a category
He goes on to say that each will be architected differently, except that — as he already convinced me back in July — RDF will be well-managed by specialty data warehouse DBMS. Read more