Application areas
Posts focusing on the use of database and analytic technologies in specific application domains. Related subjects include:
- Any subcategory
- (in Text Technologies) Specific application areas for text analytics
Notes on predictive modeling, October 10, 2014
As planned, I’m getting more active in predictive modeling. Anyhow …
1. I still believe most of what I said in a July, 2013 predictive modeling catch-all post. However, I haven’t heard as much subsequently about Ayasdi as I had expected to.
2. The most controversial part of that post was probably the claim:
I think the predictive modeling state of the art has become:
- Cluster in some way.
- Model separately on each cluster.
In particular:
- It is always possible to instead go with a single model formally.
- A lot of people think accuracy, ease-of-use, or both are better served by a true single-model approach.
- Conversely, if you have a single model that’s pretty good, it’s natural to look at the subset of the data for which it works poorly and examine that first. Voila! You’ve just done a kind of clustering.
3. Nutonian is now a client. I just had my first meeting with them this week. To a first approximation, they’re somewhat like KXEN (sophisticated math, non-linear models, ease of modeling, quasi-automagic feature selection), but with differences that start: Read more
| Categories: Ayasdi, Databricks, Spark and BDAS, Log analysis, Nutonian, Predictive modeling and advanced analytics, Revolution Analytics, Scientific research, Web analytics | 9 Comments |
Streaming for Hadoop
The genesis of this post is that:
- Hortonworks is trying to revitalize the Apache Storm project, after Storm lost momentum; indeed, Hortonworks is referring to Storm as a component of Hadoop.
- Cloudera is talking up what I would call its human real-time strategy, which includes but is not limited to Flume, Kafka, and Spark Streaming. Cloudera also sees a few use cases for Storm.
- This all fits with my view that the Current Hot Subject is human real-time data freshness — for analytics, of course, since we’ve always had low latencies in short-request processing.
- This also all fits with the importance I place on log analysis.
- Cloudera reached out to talk to me about all this.
Of course, we should hardly assume that what the Hadoop distro vendors favor will be the be-all and end-all of streaming. But they are likely to at least be influential players in the area.
In the parts of the problem that Cloudera emphasizes, the main tasks that need to be addressed are: Read more
Some stuff on my mind, September 28, 2014
1. I wish I had some good, practical ideas about how to make a political difference around privacy and surveillance. Nothing else we discuss here is remotely as important. I presumably can contribute an opinion piece to, more or less, the technology publication(s) of my choice; that can have a small bit of impact. But I’d love to do better than that. Ideas, anybody?
2. A few thoughts on cloud, colocation, etc.:
- The economies of scale of colocation-or-cloud over operating your own data center are compelling. Most of the reasons you outsource hardware manufacture to Asia also apply to outsourcing data center operation within the United States. (The one exception I can think of is supply chain.)
- The arguments for cloud specifically over colocation are less persuasive. Colo providers can even match cloud deployments in rapid provisioning and elastic pricing, if they so choose.
- Surely not coincidentally, I am told that Rackspace is deemphasizing cloud, reemphasizing colocation, and making a big deal out of Open Compute. In connection with that, Rackspace has pulled back from its leadership role in OpenStack.
- I’m hearing much more mention of Amazon Redshift than I used to. It seems to have a lot of traction as a simple and low-cost option.
- I’m hearing less about Elastic MapReduce than I used to, although I imagine usage is still large and growing.
- In general, I get the impression that progress is being made in overcoming the inherent difficulties in cloud (and even colo) parallel analytic processing. But it all still seems pretty vague, except for the specific claims being made for traction of Redshift, EMR, and so on.
- Teradata recently told me that in colocation pricing, it is common for floor space to be everything, with power not separately metered. But I don’t think that trend is a big deal, as it is not necessarily permanent.
- Cloud hype is of course still with us.
- Other than the above, I stand by my previous thoughts on appliances, clusters and clouds.
3. As for the analytic DBMS industry: Read more
Data as an asset
We all tend to assume that data is a great and glorious asset. How solid is this assumption?
- Yes, data is one of the most proprietary assets an enterprise can have. Any of the Goldman Sachs big three* — people, capital, and reputation — are easier to lose or imitate than data.
- In many cases, however, data’s value diminishes quickly.
- Determining the value derived from owning, analyzing and using data is often tricky — but not always. Examples where data’s value is pretty clear start with:
- Industries which long have had large data-gathering research budgets, in areas such as clinical trials or seismology.
- Industries that can calculate the return on mass marketing programs, such as internet advertising or its snail-mail predecessors.
*”Our assets are our people, capital and reputation. If any of these is ever diminished, the last is the most difficult to restore.” I love that motto, even if Goldman Sachs itself eventually stopped living up to it. If nothing else, my own business depends primarily on my reputation and information.
This all raises the idea — if you think data is so valuable, maybe you should get more of it. Areas in which enterprises have made significant and/or successful investments in data acquisition include: Read more
| Categories: Data mart outsourcing, eBay, Health care, Investment research and trading, Log analysis, Scientific research, Text, Web analytics | 9 Comments |
Misconceptions about privacy and surveillance
Everybody is confused about privacy and surveillance. So I’m renewing my efforts to consciousness-raise within the tech community. For if we don’t figure out and explain the issues clearly enough, there isn’t a snowball’s chance in Hades our lawmakers will get it right without us.
How bad is the confusion? Well, even Edward Snowden is getting it wrong. A Wired interview with Snowden says:
“If somebody’s really watching me, they’ve got a team of guys whose job is just to hack me,” he says. “I don’t think they’ve geolocated me, but they almost certainly monitor who I’m talking to online. Even if they don’t know what you’re saying, because it’s encrypted, they can still get a lot from who you’re talking to and when you’re talking to them.”
That is surely correct. But the same article also says:
“We have the means and we have the technology to end mass surveillance without any legislative action at all, without any policy changes.” The answer, he says, is robust encryption. “By basically adopting changes like making encryption a universal standard—where all communications are encrypted by default—we can end mass surveillance not just in the United States but around the world.”
That is false, for a myriad of reasons, and indeed is contradicted by the first excerpt I cited.
What privacy/surveillance commentators evidently keep forgetting is:
- There are many kinds of privacy-destroying information. I think people frequently overlook just how many kinds there are.
- Many kinds of organization capture that information, can share it with each other, and gain benefits from eroding or destroying privacy. Similarly, I think people overlook just how pervasive the incentive is to snoop.
- Privacy is invaded through a variety of analytic techniques applied to that information.
So closing down a few vectors of privacy attack doesn’t solve the underlying problem at all.
Worst of all, commentators forget that the correct metric for danger is not just harmful information use, but chilling effects on the exercise of ordinary liberties. But in the interest of space, I won’t reiterate that argument in this post.
Perhaps I can refresh your memory why each of those bulleted claims is correct. Major categories of privacy-destroying information (raw or derived) include:
- The actual content of your communications — phone calls, email, social media posts and more.
- The metadata of your communications — who you communicate with, when, how long, etc.
- What you read, watch, surf to or otherwise pay attention to.
- Your purchases, sales and other transactions.
- Video images, via stationary cameras, license plate readers in police cars, drones or just ordinary consumer photography.
- Monitoring via the devices you carry, such as phones or medical monitors.
- Your health and physical state, via those devices, but also inferred from, for example, your transactions or search engine entries.
- Your state of mind, which can be inferred to various extents from almost any of the other information areas.
- Your location and movements, ditto. Insurance companies also want to put monitors in cars to track your driving behavior in detail.
| Categories: Health care, Predictive modeling and advanced analytics, Surveillance and privacy, Telecommunications | 2 Comments |
An idealized log management and analysis system — from whom?
I’ve talked with many companies recently that believe they are:
- Focused on building a great data management and analytic stack for log management …
- … unlike all the other companies that might be saying the same thing 🙂 …
- … and certainly unlike expensive, poorly-scalable Splunk …
- … and also unlike less-focused vendors of analytic RDBMS (which are also expensive) and/or Hadoop distributions.
At best, I think such competitive claims are overwrought. Still, it’s a genuinely important subject and opportunity, so let’s consider what a great log management and analysis system might look like.
Much of this discussion could apply to machine-generated data in general. But right now I think more players are doing product management with an explicit conception either of log management or event-series analytics, so for this post I’ll share that focus too.
A short answer might be “Splunk, but with more analytic functionality and more scalable performance, at lower cost, plus numerous coupons for free pizza.” A more constructive and bottoms-up approach might start with: Read more
Notes and comments, May 6, 2014
After visiting California recently, I made a flurry of posts, several of which generated considerable discussion.
- My claim that Spark will replace Hadoop MapReduce got much Twitter attention — including some high-profile endorsements — and also some responses here.
- My MemSQL post led to a vigorous comparison of MemSQL vs. VoltDB.
- My post on hardware and storage spawned a lively discussion of Hadoop hardware pricing; even Cloudera wound up disagreeing with what I reported Cloudera as having said. 🙂 Sadly, there was less response to the part about the partial (!) end of Moore’s Law.
- My Cloudera/SQL/Impala/Hive apparently was well-balanced, in that it got attacked from multiple sides via Twitter & email. Apparently, I was too hard on Impala, I was too hard on Hive, and I was too hard on boxes full of cardboard file cards as well.
- My post on the Intel/Cloudera deal garnered a comment reminding us Dell had pushed the Intel distro.
- My CitusDB post picked up a few clarifying comments.
Here is a catch-all post to complete the set. Read more
The worst database developers in the world?
If the makers of MMO RPGs (Massive Multi-Player Online Role-Playing Games) aren’t quite the worst database application developers in the world, they’re at least on the short list for consideration. The makers of Guild Wars didn’t even try to have decent database functionality. A decade later, when they introduced Guild Wars 2, the database-oriented functionality (auction house, real-money store, etc.) would crash for days at a time. Lord of the Rings Online evidently had multiple issues with database functionality. Now I’m playing Elder Scrolls Online, which on the whole is a great game, but which may have the most database screw-ups of all.
ESO has been live for less than 3 weeks, and in that time:
1. There’s been a major bug in which players’ “banks” shrank, losing items and so on. Days later, the data still hasn’t been recovered. After a patch, the problem if anything worsened.
2. Guild functionality has at times been taken down while the rest of the game functioned.
3. Those problems aside, bank and guild bank functionality are broken, via what might be considered performance bugs. Problems I repeatedly encounter include:
- If you deposit a few items, the bank soon goes into a wait state where you can’t use it for a minute or more.
- Similarly, when you try to access a guild — i.e. group — bank, you often find it in an unresponsive state.
- If you make a series of updates a second apart, the game tells you you’re doing things too quickly, and insists that you slow down a lot.
- Items that are supposed to “stack” appear in 2 or more stacks; i.e., a very simple kind of aggregation is failing. There are also several other related recurring errors, which I conjecture have the same underlying cause.
In general, it seems like that what should be a collection of database records is really just a list, parsed each time an update occurs, periodically flushed in its entirety to disk, with all the performance problems you’d expect from that kind of choice.
| Categories: Fun stuff, Games and virtual worlds | 28 Comments |
DBMS2 revisited
The name of this blog comes from an August, 2005 column. 8 1/2 years later, that analysis holds up pretty well. Indeed, I’d keep the first two precepts exactly as I proposed back then:
- Task-appropriate data managers. Much of this blog is about task-appropriate data stores, so I won’t say more about them in this post.
- Drastic limitations on relational schema complexity. I think I’ve been vindicated on that one by, for example:
- NoSQL and dynamic schemas.
- Schema-on-read, and its smarter younger brother schema-on-need.
- Limitations on the performance and/or allowed functionality of joins in scale-out short-request RDBMS, and the relative lack of complaints about same.
- Funky database design from major Software as a Service (SaaS) vendors such as Workday and Salesforce.com.
- A whole lot of logs.
I’d also keep the general sense of the third precept, namely appropriately-capable data integration, but for that one the specifics do need some serious rework.
For starters, let me say: Read more
| Categories: About this blog, Business intelligence, Database diversity, EAI, EII, ETL, ELT, ETLT, Investment research and trading, NoSQL, Schema on need | 2 Comments |
Confusion about metadata
A couple of points that arise frequently in conversation, but that I don’t seem to have made clearly online.
“Metadata” is generally defined as “data about data”. That’s basically correct, but it’s easy to forget how many different kinds of metadata there are. My list of metadata kinds starts with:
- Data about data structure. This is the classical sense of the term. But please note:
- In a relational database, structural metadata is rather separate from the data itself.
- In a document database, each document might carry structure information with it.
- Other inputs to core data management functions. Two major examples are:
- Column statistics that inform RDBMS optimizers.
- Value ranges that inform partition pruning or, more generally, data skipping.
- Inputs to ancillary data management functions — for example, security privileges.
- Support for human decisions about data — for example, information about authorship or lineage.
What’s worse, the past year’s most famous example of “metadata”, telephone call metadata, is misnamed. This so-called metadata, much loved by the NSA (National Security Agency), is just data, e.g. in the format of a CDR (Call Detail Record). Calling it metadata implies that it describes other data — the actual contents of the phone calls — that the NSA strenuously asserts don’t actually exist.
And finally, the first bullet point above has a counter-intuitive consequence — all common terminology notwithstanding, relational data is less structured than document data. Reasons include:
- Relational databases usually just hold strings — or maybe numbers — with structural information being held elsewhere.
- Some document databases store structural metadata right with the document data itself.
- Some document databases store data in the form of (name, value) pairs. In some cases additional structure is imposed by naming conventions.
- Actual text documents carry the structure imposed by grammar and syntax.
Related links
- A lengthy survey of metadata kinds, biased to Hadoop (August, 2012)
- Metadata as derived data (May, 2011)
- Dataset management (May, 2013)
- Structured/unstructured … multi-structured/poly-structured (May, 2011)