Almost a year ago I wrote this post about a ViewCriteria issue when using the same attribute twice in Oracle JDeveloper 12.1.3.0. Now I came across another issue with ViewCriteria, in Oracle JDeveloper 12.2.1.0 this time, again related with a multiple insertion of an attribute but with a more complex scenario this time. Consider having an attribute with applied LOV that …
Manifest entry Weblogic-Application-Version causes log messages not to be shown on EM 12.2.1
Recently we migrated an ADF app from 12.1.3 to 12.2.1 and we faced a problem with the log messages in the application server. Specifically, the deployed application returned zero log messages when navigating to em>application>Logs>view Log messages. The log configuration and the search results are as you can see in the following screenshots: After many checks and dummy applications …
How to use SparkR in Cloudera Hadoop
Suppose you are an avid R user, and you would like to use SparkR in Cloudera Hadoop; unfortunately, as of the latest CDH version (5.7), SparkR is still not supported (and, according to a recent discussion in the Cloudera forums, we shouldn’t expect this to happen anytime soon). Is there anything you can do? Well, indeed there is. In this …
Bulk load data to HBase in Oracle Big Data Appliance
I ran into an issue recently, while trying to bulk load some data to HBase in Oracle Big Data Appliance. Following is a reproducible description and solution using the current version of Oracle Big Data Lite VM (4.4.0). Enabling HBase in Oracle Big Data Lite VM (Feel free to skip this section if you do not use Oracle Big Data …
Installing the additional R packages in Oracle Big Data Lite VM 4.4.0
In the just-released version 4.4.0 of Oracle Big Data Lite VM, as in the previous one (4.3.0.1), there is a rather large number of additional R packages to be installed by the provided script install_additional_packages.sh, i.e. 28 packages without counting their dependencies (the respective number in version 4.2.1 was only 10). Unfortunately, what has also changed is the form of …
Using ROracle with Oracle Instant Client 12c
The other day, while setting up the new Oracle R Enterprise (ORE) 1.5 client packages in a Linux server, we installed the Oracle DB Instant Client v. 12.1, as advised in the relevant documentation. Problem was, ORE failed to load, in fact due to ROracle failure: Truth is, the file libclntsh.so.11.1 did not exist, but this was expected, simply due …
Querying Big Data SQL tables with Oracle R Enterprise
I was wondering recently if I could use Oracle R Enterprise (ORE) to query Big Data SQL tables (i.e. Oracle Database external tables based on HDFS or Hive data), since I have never seen such a combination mentioned in the relevant Oracle documentation and white papers. I am happy to announce that the answer is an unconditional yes. In this …
Nonlinear regression using Spark – Part 1: Nonlinear models
Regression constitutes a very important topic in supervised learning. Its goal is to predict the value of one or more continuous target variables (responses) given the value of a -dimensional vector of input variables (predictors). More specifically, given a training data set comprising of observations , where , together with corresponding target values , the goal is to predict the …
Caution when installing Oracle R Distribution in Oracle Linux using Yum
Last week we tried to install Oracle R Distribution (ORD) in Oracle Linux 7.1 using Yum, which is the installation method recommended by Oracle. After following closely the instructions provided in the documentation, instead of the Oracle R Distribution 3.2.0, we found ourselves with the latest (3.2.3) version of GNU R installed. What had happened is that in our /etc/yum.repos.d, …
Limitations of Spark MLlib linear algebra module
A couple of days ago I stumbled upon some unexpected behavior of Spark MLlib (v. 1.5.2), while trying some ultra-simple operations on vectors. Consider the following Pyspark snippet: Clearly, what happens is that the unary operator – (minus) for vectors fails, giving errors for expressions like -x and -y+x, although x-y behaves as expected. The result of the last operation, …