Daily Archives: June 7, 2016

Impala Miscellaneous Functions

Impala Conditions with Example Impala supports the following conditional functions for testing equality, comparison operators, and nullity: ‘Case’ Example: 1)  If else select case when 20 > 10 then 20 else 15 end; Output:  20 2) If else if select case when 9 > 10 then 20 when 1 > 2 then 1.0 else 15 end; Output:  15 ===================================================================================== ‘Coalesce’ Function Example: The COALESCE function in Impala returns the first […]

PMD (Programming Mistake Detector)

PMD (Programming Mistake Detector) What is PMD? PMD aka Programming Mistake Detector is Java Source Code Analyzer. It is used to clean erroneous code in our java projects based on predefined set of rules. PMD supports the ability to write custom rules. Issues reported by PMD may not be true errors always, but rather inefficient code, i.e. the application could still function properly even if they were not corrected. PMD […]

Creating UDF and UDAF for Impala

 Installing the UDF Development Package

The output will be like below code. [cloudera@quickstart impala-udf-samples-master]$ cmake . — The C compiler identification is GNU 4.4.7 — The CXX compiler identification is GNU 4.4.7 — Check for working C compiler: /usr/bin/cc — Check for working C compiler: /usr/bin/cc — works — Detecting C compiler ABI info — Detecting C compiler ABI info – done — Check for working CXX compiler: /usr/bin/c++ […]

Postgres Commands


We can see our new table by typing this:

List of relations Schema |    Name    | Type  |  Owner ——–+————+——-+———- public | playground | table | postgres (1 row) INSERT

  Message returned if only one row was inserted. oid is the numeric OID of the inserted row. Ex: INSERT oid 1 Message returned if more than one rows were inserted. # is the number of rows […]

Postgres Installation On Centos

To install the server locally use the command line and type

To start off, we need to set the password of the PostgreSQL user (role) called “postgres”; we will not be able to access the server externally otherwise. As the local “postgres” Linux user, we are allowed to connect and manipulate the server using the psql command. In a terminal, type:

this connects as a role with same […]

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I have attended Siva’s Spark and Scala training. He is good in presentation skills and explaining technical concepts easily to everyone in the group. He is having excellent real time experience and provided enough use cases to understand each concepts. Duration of the course and time management is awesome. Happy that I found a right person on time to learn Spark. Thanks Siva!!!

Dharmeswaran ETL / Hadoop Developer Spark Nov 2016 September 21, 2017