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Presentation table contains alias which is already used

Problem: consistency check Error No. 38044

Screenshot:

Presentation table contains alias which is already used

Screenshot text:

[38044] Presentation table [TABLE] contains alias [ALIAS] which is already used.

Solution:

  • go to the presentation table that contains the alias [ALIAS]
  • double click on the presentation table name
  • go to the tab Aliases

Presentation Table - Aliases

  • select the alias
  • remove the alias
  • click OK to close the pop-up
  • check in the rpd

The error message is not displayed anymore.

Het bericht Presentation table contains alias which is already used verscheen eerst op OBIEE 24/7 | Oracle Business Intelligence.

Logical table has no defined key

Problem: consistency check warning / Error No. 39001

Screenshot:

Logical table Kalender Fact has no defined key - consistency check

Screenshot text:

[39001] Logical table [TABLE] has no defined key.

Solution:

  • go to the logical table [TABLE]
  • double click on the logical table name
  • go to the tab Keys

Logical table primary key

  • insert a Key Name (for example PK (Primairy Key))
  • select all column(s) that belong to the primairy key
  • close the pop-up
  • check in the rpd

The warning / error message is not displayed anymore.

Het bericht Logical table has no defined key verscheen eerst op OBIEE 24/7 | Oracle Business Intelligence.

Lifting the Lid on OBIEE Internals with Linux Diagnostics Tools

There comes the point in any sufficiently complex or difficult problem diagnosis that the log files in OBIEE alone are not sufficient for building up a complete picture of what’s going on. Even with the debug/trace data that Presentation Services and other components can be configured precisely to write you’re sometimes just left having to guess what is going on inside the black box of each of the OBIEE system components.

Here we’re going to look at a couple of examples of lifting the lid just a little bit further on what OBIEE is up to, using standard Linux diagnostic tools. These are not something to be reaching for in the first instance, but more getting on to a last resort. Almost always the problem is simpler than you’ll think, and leaping for an network trace or stack trace is going to be missing the wood for the trees.

Diagnostics in action

At a client recently they had a problem with a custom skin deployment on a clustered (scaled-out) OBIEE deployment. Amongst other things the skin was setting the default palette for charts (viewui/chart/dvt-graph-skin.xml), and they were seeing only 50% of chart executions pick up the custom palette – the other 50% used the default. If either entire node was shut down, things were fine, but otherwise it was a 50:50 chance what the colours would be. Most odd….

When you configure a custom skin in OBIEE you should be setting CustomerResourcePhysicalPath in instanceconfig.xml, along with CustomerResourceVirtualPath. Both these are necessary so that Presentation Services knows:

  1. Logical – How to generate URLs for content requested by the user’s browser (eg logos, CSS files, etc).
  2. Physical – How to physically reference files on the file system that are read by OBIEE itself (eg XML files, language files)

The way the client had configured their custom skin was that it was on storage local to each node, and in a node-specific path, something like this:

  • /data/instance1/s_custom/
  • /data/instance2/s_custom/

Writing out the details in hindsight always makes a problem’s root cause a lot more obvious, but at the time this was a tricky problem. Let’s start with the basics. Java Host is responsible for rendering charts, and for some reason, it was not reading the custom colour scheme file from the custom skin correctly. Presentation Services uses all the available Java Hosts in a cluster to request charts, presumably on some kind of round-robin basis. An analysis request on NODE01 has a 50:50 chance of getting its chart rendered on Java Host on NODE01 or Java Host on NODE02:


Turned all the log files up to 11 didn’t yield anything useful. For some reason half the time Java Host would just “ignore” the custom skin. Shutting down each node proved that in isolation the custom skin configuration on each node was definitely correct, because then the colours started working just fine. It was only when multiple Java Hosts across the nodes were active that there was a problem.

How Java Host picks up the custom skin is entirely undocumented, and I ended up figuring out that it must get the path to the skin as part of the chart request from Presentation Services. Since Presentation Services on NODE01 has been configured with a CustomerResourcePhysicalPath of /data/instance1/s_custom/, Java Host on NODE02 would fail to find this path (since on NODE02 the skin is located at /data/instance2/s_custom/) and so fall back on the default. This was my hypothesis that I then proved by making the path available for each skin available on each node (symlink, or using a standard path would also have worked, eg /data/shared/s_custom, or even better, a shared mount point), and from there everything worked just fine.

But a hypothesis and successful resolution alone wasn’t entirely enough. Sure the client was happy, but there was that little itch, that unknown “black box” system that appeared to behave how I had deduced, but could we know for sure?

tcpdump – network analysis

All of the OBIEE components communicate with each other and the outside world over TCP. When Presentation Services wants a chart rendered it does so by sending a request to Java Host – over TCP. Using the tcpdump tool we can see that in action, and inspect what gets sent:

$ sudo tcpdump -i venet0 -i lo -nnA 'port 9810'

The -A flag capture the ASCII representation of the packet; use -X if you want ASCII and hex. Port 9810 is the Java Host listen port.

The output looks like this:


You’ll note that in this case it’s intra-node communication, i.e. src and dest IP addresses are the same. The port for Java Host (9810) is clear, and we can verify that the src port (38566) is Presentation Services with the -p (process) flag of netstat:

$ sudo netstat -pn |grep 38566
tcp        0      0 192.168.10.152:38566        192.168.10.152:9810         ESTABLISHED 5893/sawserver

So now if you look in a bit more detail at the footer of the request from Presentation Services that tcpdump captured you’ll see loud and clear (relatively) the custom skin path with the graph customisation file:


Proof that the Presentation Services is indeed telling Java Host where to go and look for the custom attributes (including colours)! NB this is on a test environment, so that paths vary from the /data/instance... example above)

strace – system call analysis

So tcpdump gives us the smoking gun, but can we find the corpse as well? Sure we can! strace is a tool for tracing system calls, and a fantastically powerful one, but here’s a very simple example:

$strace -o /tmp/obijh1_strace.log -f -p $(pgrep -f obijh1)

-o means to write it to file, -f follows child processes as well, and -p passes the process id that strace should attach to. Have set the trace running I run my chart, and then go and pick through my trace file.

We know it’s the dvt-graph-skin.xml file that Java Host should be reading to pick up the custom colours, so let’s search for that:


Well there we go – Java Host went to go and look for the skin in the path that it was given by Presentation Services, and couldn’t find it. From there it’ll fall back on the product defaults.

Right Tool, Right Job

As as I said at the top of this article, these diagnostic tools are not the kind of things you’d be using day to day. Understanding their output is not always easy and it’s probably easy to do more harm than good with false assumption about what a trace is telling you. But, in the right situations, they are great for really finding out what is going on under the covers of OBIEE.

New Oracle Big Data Quick-Start Packages from Rittman Mead

Many organisations using Oracle’s business intelligence and data warehousing tools are now looking to extend their capabilities using “big data” technologies. Customers running their data warehouses on Oracle Databases are now looking to use Hadoop to extend their storage capacity whilst offloading initial data loading and ETL to this complementary platform; other customers are using Hadoop and Oracle’s Big Data Appliance to add new capabilities around unstructured and sensor data analysis, all at considerably lower-cost than traditional database storage.

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In addition, as data and analytics technologies and capabilities have evolved, there has never been a better opportunity to reach further into your data to exploit more value. Big Data platforms, Data Science methods and data discovery technologies make it possible to unlock the power of your data and put it in the hands of your  executives and team members – but what is it worth to you? What’s the value to your organisation of exploring deeper int the data you have, and how do you show return?

Many organisations have begin to explore Big Data technologies to understand where they can exploit value and extend their existing analytics platforms, but what’s the business case? The good news is, using current platforms, and following architectures like the Oracle Information Management and Big Reference Architecture written in conjunction with Rittman Mead, the foundation is in place to unlock a range of growth opportunities. Finding new value in existing data, predictive analytics, data discovery, reducing the cost of data storage, ETL offloading are all starter business cases proven to return value quickly.

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To help you start on the Oracle big data journey, Rittman Mead have put together two quick-start packages focuses on the most popular Oracle customer use-cases;

If this sounds like something you or your organization might be interested in, take a look at our new Quick Start Oracle Big Data and Big Data Discovery packages from Rittman Mead home page, or drop me an email at mark.rittman@rittmanmead.com and I’ll let you know how we can help.

RM BI Forum 2015 : Justification Letters for Employers

(Thanks to Christian Berg @Nephentur for the suggestion, and acknowledgements to ODTUG KScope for the original idea – our favourite conference after the BI Forum)

The Rittman Mead BI Forum 2015 promises to be our best BI Forum yet, with fantastic speakers at each event, keynotes and guest speakers from Oracle and John Foreman, author of the bestselling book “Data Smart”, a data visualisation challenge and an optional one-day masterclass on delivering Oracle’s new Information Management and Big Data reference architecture by Rittman Mead’s Mark Rittman and Jordan Meyer. Uniquely amongst Oracle BI events we keep the numbers attending very limited and run just a single stream at each event, so everyone takes part in the same sessions and gets to meet all the attendees and speakers over the three days.

Sometimes though, management within organizations require special justification for team members to attend events like these, and to help you put your case together and get across the unique education and networking benefits of the Rittman Mead BI Forum, we’ve prepared justification letters for you to complete with your details, one each for the Brighton and Atlanta events. Click on the links below to download sample justification letters for the Brighton BI Forum running on May 6th-8th 2015, and the Atlanta one running the week after on May 13th-15th 2015:

Full details on the BI Forum 2015 agenda and how to register can be found on the Rittman Mead BI Forum 2015 home page, with registration open until the weekend before each event – hurry though as attendee numbers are strictly limited.