RDF and graphs
Analysis of data management technology optimized for RDF-formatted and/or graph data.
Notes on the analysis of large graphs
This post is part of a series on managing and analyzing graph data. Posts to date include:
- Graph data model basics
- Relationship analytics definition
- Relationship analytics applications
- Analysis of large graphs (this post)
My series on graph data management and analytics got knocked off-stride by our website difficulties. Still, I want to return to one interesting set of issues — analyzing large graphs, specifically ones that don’t fit comfortably into RAM on a single server. By no means do I have the subject figured out. But here are a few notes on the matter.
How big can a graph be? That of course depends on:
- The number of nodes. If the nodes of a graph are people, there’s an obvious upper bound on the node count. Even if you include their houses, cars, and so on, you’re probably capped in the range of 10 billion.
- The number of edges. (Even more important than the number of nodes.) If every phone call, email, or text message in the world is an edge, that’s a lot of edges.
- The typical size of a (node, edge, node) triple. I don’t know why you’d have to go much over 100 bytes post-compression*, but maybe I’m overlooking something.
*Even if your graph has 10 billion nodes, those can be tokenized in 34 bits, so the main concern is edges. Edges can include weights, timestamps, and so on, but how many specifics do you really need? At some point you can surely rely on a pointer to full detail stored elsewhere.
The biggest graph-size estimates I’ve gotten are from my clients at Yarcdata, a division of Cray. (“Yarc” is “Cray” spelled backwards.) To my surprise, they suggested that graphs about people could have 1000s of edges per node, whether in:
- An intelligence scenario, perhaps with billions of nodes and hence trillions of edges.
- A telecom user-analysis case, with perhaps 100 million nodes and hence 100s of billions of edges.
Yarcdata further suggested that bioinformatics use cases could have node counts higher yet, characterizing Bio2RDF as one of the “smaller” ones at 22 billion nodes. In these cases, the nodes/edge average seems lower than in people-analysis graphs, but we’re still talking about 100s of billions of edges.
Recalling that relationship analytics boils down to finding paths and subgraphs, the naive relational approach to such tasks would be: Read more
| Categories: Analytic technologies, Aster Data, Data models and architecture, Hadoop, Health care, MapReduce, RDF and graphs, Scientific research, Telecommunications, Yarcdata and Cray | 15 Comments |
Relationship analytics application notes
This post is part of a series on managing and analyzing graph data. Posts to date include:
- Graph data model basics
- Relationship analytics definition
- Relationship analytics applications (this post)
- Analysis of large graphs
In my recent post on graph data models, I cited various application categories for relationship analytics. For most applications, it’s hard to get a lot of details. Reasons include:
- In adversarial domains such as national security, anti-fraud, or search engine ranking, it’s natural to keep algorithms secret.
- The big exception – influencer analytics, aka social network analysis — is obscured by a major hype/reality gap (so, come to think of it, is a lot of other predictive modeling).
Even so, it’s fairly safe to say:
- Much of relationship analytics is about subgraph pattern matching.
- Much of relationship analytics is about identifying subgraph patterns that are predictive of certain characteristics or outcomes.
- An important kind of relationship analytics challenge is to identify influential individuals.
| Categories: Predictive modeling and advanced analytics, RDF and graphs, Telecommunications | 5 Comments |
Terminology: Relationship analytics
This post is part of a series on managing and analyzing graph data. Posts to date include:
- Graph data model basics
- Relationship analytics definition (this post)
- Relationship analytics applications
- Analysis of large graphs
In late 2005, I encountered a company called Cogito that was using a graphical data manager to analyze relationships. They called this “relational analytics”, which I thought was a terrible name for something that they were trying to claim should NOT be done in a relational DBMS. On the spot, I coined relationship analytics as an alternative. A business relationship ensued, which included a short white paper. Cogito didn’t do so well, however, and for a while the term “relationship analytics” faltered too. But recently it’s made a bit of a comeback, having been adopted by Objectivity, Qlik Tech, Yarcdata and others.
“Relationship analytics” is not a perfect name, both because it’s longish and because it might over-connote a social-network focus. But then, no other term would be perfect either. So we might as well stick with it.
In that case, “relationship analytics” could use an actual definition, preferably one a little heftier than just:
Analytics on graphs.
| Categories: Cogito and 7 Degrees, Objectivity and Infinite Graph, QlikTech and QlikView, RDF and graphs, Yarcdata and Cray | 6 Comments |
Notes on graph data management
This post is part of a series on managing and analyzing graph data. Posts to date include:
- Graph data model basics (this post)
- Relationship analytics definition
- Relationship analytics applications
- Analysis of large graphs
Interest in graph data models keeps increasing. But it’s tough to discuss them with any generality, because “graph data model” encompasses so many different things. Indeed, just as all data structures can be mapped to relational ones, it is also the case that all data structures can be mapped to graphs.
Formally, a graph is a collection of (node, edge, node) triples. In the simplest case, the edge has no properties other than existence or maybe direction, and the triple can be reduced to a (node, node) pair, unordered or ordered as the case may be. It is common, however, for edges to encapsulate additional properties, the canonical examples of which are:
- Weight. Usually, the intuition here is that the weight is a number indicating the strength of the connection. This is generally derived from more basic data.
- Kind. The edge can encapsulate one or more descriptors indicating the kind of relationship between the nodes.
Many of the graph examples I can think of fit into four groups: Read more
| Categories: RDF and graphs, Telecommunications, Workday | 6 Comments |
IBM DB2 10
Shortly before Tuesday’s launch of DB2 10, IBM’s Conor O’Mahony checked in for a relatively non-technical briefing.* More precisely, this is about DB2 for “distributed” systems, aka LUW (Linux/Unix/Windows); some of the features have already been in the mainframe version of DB2 for a while. IBM is graciously permitting me to post the associated DB2 10 announcement slide deck.
*I hope any errors in interpretation are minor.
Major aspects of DB2 10 include new or improved capabilities in the areas of:
- Compression.
- Analytic query performance.
- Data ingest.
- Multi-temperature data management.
- Workload management.
- Graph management/relationship analytics.
- Time-travel, bitemporal features, and bitemporal time-travel.
Of course, there are various other enhancements too, including to security (fine-grained access control), Oracle compatibility, and DB2 pureScale. Everything except the pureScale part is also reflected in IBM InfoSphere Warehouse, which is a near-superset of DB2.*
*Also, the data ingest part isn’t in base DB2.
| Categories: Data warehousing, Database compression, IBM and DB2, RDF and graphs, Solid-state memory, Workload management | 3 Comments |
Aster Data business trends
Last month, I reviewed with the Aster Data folks which markets they were targeting and selling into, subsequent to acquisition by their new orange overlords. The answers aren’t what they used to be. Aster no longer focuses much on what it used to call frontline (i.e., low-latency, operational) applications; those are of course a key strength for Teradata. Rather, Aster focuses on investigative analytics — they’ve long endorsed my use of the term — and on the batch run/scoring kinds of applications that inform operational systems.
| Categories: Analytic technologies, Application areas, Aster Data, Data warehousing, DataStax, Liberty and privacy, RDF and graphs, Teradata, Web analytics | 1 Comment |
Vertica as an analytic platform
Vertica 5.0 is coming out today, and delivering the down payment on Vertica’s analytic platform strategy. In Vertica lingo, there’s now a Vertica SDK (Software Development Kit), featuring Vertica UDT(F)s* (User-Defined Transform Functions). Vertica UDT syntax basics start: Read more
| Categories: Analytic technologies, Data warehousing, GIS and geospatial, Predictive modeling and advanced analytics, RDF and graphs, Vertica Systems, Workload management | 6 Comments |
Investigative analytics and derived data: Enzee Universe 2011 talk
I’ll be speaking Monday, June 20 at IBM Netezza’s Enzee Universe conference. Thus, as is my custom:
- I’m posting draft slides.
- I’m encouraging comment (especially in the short time window before I have to actually give the talk).
- I’m offering links below to more detail on various subjects covered in the talk.
The talk concept started out as “advanced analytics” (as opposed to fast query, a subject amply covered in the rest of any Netezza event), as a lunch break in what is otherwise a detailed “best practices” session. So I suggested we constrain the subject by focusing on a specific application area — customer acquisition and retention, something of importance to almost any enterprise, and which exploits most areas of analytic technology. Then I actually prepared the slides — and guess what? The mix of subjects will be skewed somewhat more toward generalities than I first intended, specifically in the areas of investigative analytics and derived data. And, as always when I speak, I’ll try to raise consciousness about the issues of liberty and privacy, our options as a society for addressing them, and the crucial role we play as an industry in helping policymakers deal with these technologically-intense subjects.
Slide 3 refers back to a post I made last December, saying there are six useful things you can do with analytic technology:
- Operational BI/Analytically-infused operational apps: You can make an immediate decision.
- Planning and budgeting: You can plan in support of future decisions.
- Investigative analytics (multiple disciplines): You can research, investigate, and analyze in support of future decisions.
- Business intelligence: You can monitor what’s going on, to see when it necessary to decide, plan, or investigate.
- More BI: You can communicate, to help other people and organizations do these same things.
- DBMS, ETL, and other “platform” technologies: You can provide support, in technology or data gathering, for one of the other functions.
Slide 4 observes that investigative analytics:
- Is the most rapidly advancing of the six areas …
- … because it most directly exploits performance & scalability.
Slide 5 gives my simplest overview of investigative analytics technology to date: Read more
Whither MarkLogic?
My clients at MarkLogic have a new CEO, Ken Bado, even though former CEO Dave Kellogg was quite successful. If you cut through all the happy talk and side issues, the reason for the change is surely that the board wants to see MarkLogic grow faster, and specifically to move beyond its traditional niches of publishing (especially technical publishing) and national intelligence.
So what other markets could MarkLogic pursue? Before Ken even started work, I sent over some thoughts. They included (but were not limited to): Read more
| Categories: MarkLogic, Object, RDF and graphs, Structured documents | 6 Comments |
Analytic performance — the persistent need for speed
Analytic DBMS and other analytic platform technologies are much faster than they used to be, both in absolute and price/performance terms. So the question naturally arises, “When is the performance enough?” My answer, to a first approximation, is “Never.” Obviously, your budget limits what you can spend on analytics, and anyhow the benefit of incremental expenditure at some point can grow quite small. But if analytic processing capabilities were infinite and free, we’d do a lot more with analytics than anybody would consider today.
I have two lines of argument supporting this view. One is application-oriented. Machine-generated data will keep growing rapidly. So using that data requires ever more processing resources as well. Analytic growth, rah-rah-rah; company valuation, sis-boom-bah. Application areas include but are not at all limited to marketing, law enforcement, investing, logistics, resource extraction, health care, and science.
The other approach is to point out some computational areas where vastly more analytic processing resources could be used than are available today. Consider, if you will, statistical modeling, graph analytics, optimization, and stochastic planning. Read more
| Categories: Analytic technologies, RDF and graphs | Leave a Comment |