Hadoop

[navissar]

Hi experts!
I've been asked a very broad question, and didn't manage to find a very good answer. Can Cognos work directly over Hadoop? Does it have to be bigInsights, or can we use hortonworks, for instance? Can it work over Hive and PIG, just hive, just PIG? Anything else I should know?
Your help will be deeply appreciated.

[bdbits]

This is a bit sketchy and I haven't had a chance to follow up on it, but attended a session on hadoop at IOD 2013. No, you do not have to have BigInsights. From my notes at the time (Nov 2013), 10.2.1 supported Apache Hive 0.8 and 0.9 (or any commercial version based on them). They had Hive2 and Apache 0.11 and 0.12 in labs but not yet released (maybe by now). I remember something was said about PIG, but sadly it does not appear I made any notes about it.

You have to be sure to use the JDBC drivers corresponding to your server version, otherwise it is pretty much like any data source.

Some other stuff straight from my notes:
* Keep data as strings - Cognos QE will cast it as needed
* Constraints to be aware of
      Join predicates only support equality
      IN does not allow subqueries
      Cannot use all/any/some
      No set operations (unions have limitations)
      May need to use pass-through HiveQL
* Generally, increased local processing due to current limitations wrt to typical Cognos queries
* Hive does have catalogs/schemas - you may need to specify this in the connection string setup
* HiveQL will let you code (java) user-defined scalar/tabular functions
* Likewise aggregate functions, but need syntax of Aggregate:qualification.function()

Though written for IBM products, the steps in here show how to set up your data source: https://www.ibm.com/developerworks/library/ba-cognosbi10-infospherebiginsights/index.html
See also: http://www-01.ibm.com/support/docview.wss?uid=swg21642056

I haven't looked but there may be more up-to-date information on developerworks.

I want to do a PoC on hadoop but have not had a project to justify the time so it comes out of "research time" which is pretty limited for me. If you do something, let us know how it works out.

[navissar]

Thanks! You're a real light-saber.  :)

[Cognos8]

Hi,

If you have done any POC on cognos integrating with Hadoop  let me know. I just started this analysis. Thanks