Tag: MADLib

Software for High Performance Advanced Analytics

Strata+Hadoop World week is a good opportunity to update the list of platforms for high-performance advanced analytics.  Vendors are hustling this week to announce their latest enhancements; I’ll post updates as needed.

First some definition.  The scope of this analysis includes software with the following properties:

  • Support for supervised and unsupervised machine learning
  • Support for distributed processing
  • Open platform or multi-vendor platform support
  • Availability of commercial support

There are three main “architectures” for high-performance advanced analytics available today:

  • Integration with an MPP database through table functions
  • Push-down integration with Hadoop
  • Native distributed computing, freestanding or co-located with Hadoop

I’ve written previously about the importance of distributed computing for high-performance predictive analytics, why it’s difficult to deliver and potentially disruptive to the analytics ecosystem.

This analysis excludes software that runs exclusively in a single vendor’s data platform (such as Netezza Analytics, Oracle Advanced Analytics or Teradata Aster‘s built-in analytic functions.)  While each of these vendors seeks to use advanced analytics to differentiate its data warehousing products, most enterprises are unwilling to invest in an analytics architecture that promotes vendor lock-in.  In my opinion, IBM, Oracle and Teradata should consider open sourcing their machine learning libraries, since they’re effectively giving them away anyway.

This analysis also excludes open source libraries “in the wild” (such as Vowpal Wabbit) that lack significant commercial support.

Open Source Software

H2O 

Distributor: H2O.ai (formerly 0xdata)

H20 is an open source distributed in-memory computing platform designed for deployment in Hadoop or free-standing clusters. Current functionality (Release 2.8.4.4) includes Cox Proportional Hazards modeling, Deep Learning, generalized linear models, gradient boosted classification and regression, k-Means clustering, Naive Bayes classifier, principal components analysis, and Random Forests. The software also includes tooling for data transformation, model assessment and scoring.   Users interact with the software through a web interface, a REST API or the h2o package in R.  H2O runs on Spark through the Sparkling Water interface, which includes a new Python API.

H2O.ai provides commercial support for the open source software.  There is a rapidly growing user community for H2O, and H2O.ai cites public reference customers such as Cisco, eBay, Paypal and Nielsen.

MADLib 

Distributor: Pivotal Software

MADLib is an open source machine learning library with a SQL interface that runs in Pivotal Greenplum Database 4.2 or PostgreSQL 9.2+ (as of Release 1.7).  While primarily a captive project of Pivotal Software — most of the top contributors are Pivotal or EMC employees — the support for PostgreSQL qualifies it for this list.    MADLib includes rich analytic functionality, including ten different regression methods, linear systems, matrix factorization, tree-based methods, association rules, clustering, topic modeling, text analysis, time series analysis and dimensionality reduction techniques.

Mahout

Distributor: Apache Software Foundation

Mahout is an eclectic machine learning project incepted in 2011 and currently included in major Hadoop distributions, though it seems to be something of an embarrassment to the community.  The development cadence on Mahout is very slow, as key contributors appear to have abandoned the project three years ago.   Currently (Release 0.9), the project includes twenty algorithms; five of these (including logistic regression and multilayer perceptron) run on a single node only, while the rest run through MapReduce.  To its credit, the Mahout team has cleaned up the software, deprecating unsupported functionality and mandating that all future development will run in Spark.  For Release 1.0, the team has announced plans to deliver several existing algorithms in Spark and H2O, and also to deliver something for Flink (for what that’s worth).  Several commercial vendors, including Predixion Software and RapidMiner leverage Mahout tooling in the back end for their analytic packages, though most are scrambling to rebuild on Spark.

Spark

Distributor: Apache Software Foundation

Spark is currently the platform of choice for open source high-performance advanced analytics.  Spark is a distributed in-memory computing framework with libraries for SQL, machine learning, graph analytics and streaming analytics; currently (Release 1.2) it supports Scala, Python and Java APIs, and the project plans to add an R interface in Release 1.3.  Spark runs either as a free-standing cluster, in AWS EC2, on Apache Mesos or in Hadoop under YARN.

The machine learning library (MLLib) currently (1.2) includes basic statistics, techniques for classification and regression (linear models, Naive Bayes, decision trees, ensembles of trees), alternating least squares for collaborative filtering, k-means clustering, singular value decomposition and principal components analysis for dimension reduction, tools for feature extraction and transformation, plus two optimization primitives for developers.  Thanks to large and growing contributor community, Spark MLLib’s functionality is expanding faster than any other open source or commercial software listed in this article.

For more detail about Spark, see my Apache Spark Page.

Commercial Software

Alpine Chorus

Vendor: Alpine Data Labs

Alpine targets a business user persona with a visual workflow-oriented interface and push-down integration with analytics that run in Hadoop or relational databases.  Although Alpine claims support for all major Hadoop distributions and several MPP databases, in practice most customers seem to use Alpine with Pivotal Greenplum database.  (Alpine and Greenplum have common roots in the EMC ecosystem).   Usability is the product’s key selling point, and the analytic feature set is relatively modest; however, Chorus’ collaboration and data cataloguing capabilities are unique.  Alpine’s customer list is growing; the list does not include a recent win (together with Pivotal) at a large global retailer.

dbLytix

Vendor: Fuzzy Logix

dbLytix is a library of more than eight hundred functions for advanced analytics; analytics run as database table functions and are currently supported in Informix, MySQL, Netezza, ParAccel, SQL Server, Sybase IQ, Teradata Aster and Teradata Database.  Embedded in SQL, analytics may be invoked from a range of application, including custom web interfaces, Microsoft Excel, popular BI tools, SAS or SPSS.   The software is highly extensible, and Fuzzy Logix offers a team of well-qualified consultants and developers for custom applications.

For those seeking the absolute cutting edge in advanced analytics, Fuzzy’s Tanay Zx Series offers more than five hundred analytic functions designed to run on GPU chips.  Tanay is available either as a software library or as an analytic appliance.

IBM SPSS Analytic Server

Vendor: IBM

Analytic Server serves as a Hadoop back end for IBM SPSS Modeler, a mature analytic workbench targeted to business users (licensed separately).  The product, which runs on Apache Hadoop, Cloudera CDH, Hortonworks HDP and IBM BigInsights, enables push-down MapReduce for a limited number of Modeler nodes.  Analytic Server supports most SPSS Modeler data preparation nodes, scoring for twenty-four different modeling methods, and model-building operations for linear models, neural networks and decision trees.  The cadence of enhancements for this product is very slow; first released in May 2013, IBM has released a single maintenance release since then.

RapidMiner Radoop

Vendor: RapidMiner

(Updated for Release 2.2)

RapidMiner targets a business user persona with a “code-free” user interface and deep selection of analytic features.  Last June, the company acquired Radoop, a three-year-old business partner based in Budapest.  Radoop brings to RapidMiner the ability to push down analytic processing into Hadoop using a mix of MapReduce, Mahout, Hive, Pig and Spark operations.

RapidMiner Radoop 2.2 supports more than fifty operators for data transformation, plus the ability to implement custom HiveQL and Pig scripts.  For machine learning, RapidMiner supports k-means, fuzzy k-means and canopy clustering, PCA, correlation and covariance matrices, Naive Bayes classifier and two Spark MLLib algorithms (logistic regression and decision trees); Radoop also supports Hadoop scoring capabilities for any model created in RapidMiner.

Support for Hadoop distributions is excellent, including Cloudera CDH, Hortonworks HDP, Apache Hadoop, MapR, Amazon EMR and Datastax Enterprise.  As of Release 2.2, Radoop supports Kerberos authentication.

Revolution R Enterprise

Vendor: Revolution Analytics

Revolution R Enterprise bundles a number of components, including Revolution R, an enhanced and commercially supported R distribution, a Windows IDE, integration tools and ScaleR, a suite of distributed algorithms for predictive analytics with an R interface.  A little over a year ago, Revolution released its version 7.0, which enables ScaleR to integrate with Hadoop using push-down MapReduce.   The mix of techniques currently supported in Hadoop includes tools for data transformation, descriptive statistics, linear and logistic regression, generalized linear models, decision trees, ensemble models and k-means clustering.   Revolution Analytics supports ScaleR in Cloudera, Hortonworks and MapR; Teradata Database; and in free-standing clusters running on IBM Platform LSF or Windows Server HPC.  Microsoft recently announced that it will acquire Revolution Analytics; this will provide the company with additional resources to develop and enhance the platform.

SAS High Performance Analytics

Vendor: SAS

SAS High Performance Analytics (HPA) is a distributed in-memory analytics engine that runs in Teradata, Greenplum or Oracle appliances, on commodity hardware or co-located in Hadoop (Apache, Cloudera or Hortonworks).  In Hadoop, HPA can be deployed either in a symmetric configuration (SAS instance on each DataNode) or in an asymmetric configuration (SAS deployed on dedicated “Analysis” nodes within the Hadoop cluster.)  While an asymmetric architecture seems less than ideal (due to the need for data movement and shuffling), it reduces the need to upgrade the hardware on every node and reduces SAS software licensing costs.

Functionally, there are five different bundles, for statistics, data mining, text mining, econometrics and optimization; each of these is separately licensed.  End users leverage the algorithms from SAS Enterprise Miner, which is also separately licensed.  Analytic functionality is rich compared to available high-performance alternatives, but existing SAS users will be surprised to see that many techniques available in SAS/STAT are unavailable in HPA.

SAS first introduced HPA in December, 2011 with great fanfare.  To date the product lacks a single public reference customer; this could mean that SAS’ Marketing organization is asleep at the switch, or it could mean that customer success stories with the product are few and far between.  As always with SAS, cost is an issue with prospective customers; other issues cited by customers who have evaluated the product include HPA’s inability to run existing programs developed in Legacy SAS, and concerns about the proprietary architecture. Interestingly, SAS no longer talks up this product in venues like Strata, pointing prospective customers to SAS In-Memory Statistics for Hadoop (see below) instead.

SAS In-Memory Statistics for Hadoop

Vendor: SAS

SAS In-Memory Statistics for Hadoop (IMSH) is an analytics application that runs on SAS’ “other” distributed in-memory architecture (SAS LASR Server).  Why does SAS have two in-memory architectures?  Good luck getting SAS to explain that in a coherent manner.  The best explanation, so far as I can tell, is a “mud-on-the-wall” approach to new product development.

Functionally, IMSH Release 2.5 supports data prep with SAS DS2 (an object-oriented language), descriptive statistics, classification and regression trees (C4.5), forecasting, general and generalized linear models, logistic regression, a Random Forests lookalike, clustering, association rule mining, text mining and a recommendation system.   Users interact with the product through SAS Studio, a web-based IDE introduced in SAS 9.4.

Overall, IMSH is a better value than HPA.  SAS prices this software based on the number of cores in the servers upon which it is deployed; while I can’t disclose the list price per core, it’s fair to say that any configuration beyond a sandbox will rapidly approach seven figures for the first year fee.

Skytree

Product: Skytree Infinity

Skytree began life as an academic machine learning project (FastLab, at Georgia Tech); the developers shopped the distributed machine learning core to a number of vendors and, finding no buyers, launched as a commercial software vendor in January 2013.  Recently rebranded from Skytree Server to Skytree Infinity, the product now includes modules for data marshaling and preparation that run on Spark.  Distributed algorithms can run as a free-standing cluster or co-located in Hadoop under YARN.  The product has a programming interface; the vendor claims ability to run from R, Weka, C++ and Python.   Neither Skytree’s modest list of algorithms nor its short list of public reference customers has changed in the past two years.

Distributed Analytics: A Primer

Can we leverage distributed computing for machine learning and predictive analytics? The question keeps surfacing in different contexts, so I thought I’d take a few minutes to write an overview of the topic.

The question is important for four reasons:

  • Source data for analytics frequently resides in distributed data platforms, such as MPP appliances or Hadoop;
  • In many cases, the volume of data needed for analysis is too large to fit into memory on a single machine;
  • Growing computational volume and complexity requires more throughput than we can achieve with single-threaded processing;
  • Vendors make misleading claims about distributed analytics in the platforms they promote.

First, a quick definition of terms.  We use the term parallel computing to mean the general practice of dividing a task into smaller units and performing them in parallel; multi-threaded processing means the ability of a software program to run multiple threads (where resources are available); and distributed computing means the ability to spread processing across multiple physical or virtual machines.

The principal benefit of parallel computing is speed and scalability; if it takes a worker one hour to make one hundred widgets, one hundred workers can make ten thousand widgets in an hour (ceteris paribus, as economists like to say).  Multi-threaded processing is better than single-threaded processing, but shared memory and machine architecture impose a constraint on potential speedup and scalability.  In principle, distributed computing can scale out without limit.

The ability to parallelize a task is inherent in the definition of the task itself.  Some tasks are easy to parallelize, because computations performed by each worker are independent of all other workers, and the desired result set is a simple combination of the results from each worker; we call these tasks embarrassingly parallel.   A SQL Select query is embarrassingly parallel; so is model scoring; so are many of the tasks in a text mining process, such as word filtering and stemming.

A second class of tasks requires a little more effort to parallelize.  For these tasks, computations performed by each worker are independent of all other workers, and the desired result set is a linear combination of the results from each worker.  For example, we can parallelize computation of the mean of a distributed database by computing the mean and row count independently for each worker, then compute the grand mean as the weighted mean of the worker means.  We call these tasks linear parallel.

There is a third class of tasks, which is harder to parallelize because the data must be organized in a meaningful way.  We call a task data parallel if computations performed by each worker are independent of all other workers so long as each worker has a “meaningful” chunk of the data.  For example, suppose that we want to build independent time series forecasts for each of three hundred retail stores, and our model includes no cross-effects among stores; if we can organize the data so that each worker has all of the data for one and only one store, the problem will be embarrassingly parallel and we can distribute computing to as many as three hundred workers.

While data parallel problems may seem to be a natural application for processing inside an MPP database or Hadoop, there are two constraints to consider.  For a task to be data parallel, the data must be organized in chunks that align with the business problem.  Data stored in distributed databases rarely meets this requirement, so the data must be shuffled and reorganized prior to analytic processing, a process that adds latency.  The second constraint is that the optimal number of workers depends on the problem; in the retail forecasting problem cited above, the optimal number of workers is three hundred.  This rarely aligns with the number of nodes in a distributed database or Hadoop cluster.

There is no generally agreed label for tasks that are the opposite of embarrassingly parallel; for convenience, I use the term orthogonal to describe a task that cannot be parallelized at all.  In analytics, case-based reasoning is the best example of this, as the method works by examining individual cases in a sequence.  Most machine learning and predictive analytics algorithms fall into a middle ground of complex parallelism; it is possible to divide the data into “chunks” for processing by distributed workers, but workers must communicate with one another, multiple iterations may be required and the desired result is a complex combination of results from individual workers.

Software for complex machine learning tasks must be expressly designed and coded to support distributed processing.  While it is physically possible to install open source R or Python in a distributed environment (such as Hadoop), machine learning packages for these languages run locally on each node in the cluster.  For example, if you install open source R on each node in a twenty-four node Hadoop cluster and try to run logistic regression you will end up with twenty-four logistic regression models developed separately for each node.  You may be able to use those results in some way, but you will have to program the combination yourself.

Legacy commercial tools for advanced analytics provide only limited support for parallel and distributed processing.  SAS has more than 300 procedures in its legacy Base and STAT software packages; only a handful of these support multi-threaded (SMP) operations on a single machine;  nine PROCs can support distributed processing (but only if the customer licenses an additional product, SAS High-Performance Statistics).  IBM SPSS Modeler Server supports multi-threaded processing but not distributed processing; the same is true for Statistica.

The table below shows currently available distributed platforms for predictive analytics; the table is complete as of this writing (to the best of my knowledge).

Distributed Analytics Software, May 2014

Several observations about the contents of this table:

(1) There is currently no software for distributed analytics that runs on all distributed platforms.

(2) SAS can deploy its proprietary framework on a number of different platforms, but it is co-located and does not run inside MPP databases.  Although SAS claims to support HPA in Hadoop, it seems to have some difficulty executing on this claim, and is unable to describe even generic customer success stories.

(3) Some products, such as Netezza and Oracle, aren’t portable at all.

(4) In theory, MADLib should run in any SQL environment, but Pivotal database appears to be the primary platform.

To summarize key points:

— The ability to parallelize a task is inherent in the definition of the task itself.

— Most “learning” tasks in advanced analytics tasks are not embarrassingly parallel.

— Running a piece of software on a distributed platform is not the same as running it in distributed mode.  Unless the software is expressly written to support distributed processing, it will run locally, and the user will have to figure out how to combine the results from distributed workers.

Vendors who claim that their distributed data platform can perform advanced analytics with open source R or Python packages without extra programming are confusing predictive model “learning” with simpler tasks, such as scoring or SQL queries.