Daily Archives: June 7, 2016

Impala Miscellaneous Functions

This entry was posted in Impala on June 7, 2016 by Siva

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)

This entry was posted in Java on June 7, 2016 by Siva

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

This entry was posted in Hadoop Impala and tagged impala impala aggregate functions impala userdefinedfunctions impalaudafs impalaudfs on June 7, 2016 by Shiva Balena

Installing the UDF Development Package


 Get the quickstart VM
 sudo yum install gcc-c++ cmake boost-devel
 sudo yum install impala-udf-devel
 download <a href="https://github.com/cloudera/impala-udf-samples/archive/master.zip" target="_blank" rel="nofollow">https://github.com/cloudera/impala-udf-samples/archive/master.zip</a> unzip above cd into ../impala-udf-samples-master
 cmake .

Get the quickstart VM

sudo yum install gcc-c++ cmake boost-devel

sudo yum install impala-udf-devel

download <a href="https://github.com/cloudera/impala-udf-samples/archive/master.zip" target="_blank" rel="nofollow">https://github.com/cloudera/impala-udf-samples/archive/master.zip</a> unzip above cd into ../impala-udf-samples-master

cmake .

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

This entry was posted in PostGres and tagged postgres postgres commands pssql pssqlcommands on June 7, 2016 by Shiva Balena

CREATE


CREATE TABLE playground3 (
equip_id serial PRIMARY KEY,
type varchar (50) NOT NULL,
color varchar (25) NOT NULL,
location varchar(25) check (location in ('north', 'south', 'west', 'east', 'northeast', 'southeast', 'southwest', 'northwest')),
install_date date
);

CREATE TABLE playground3 (

equip_id serial PRIMARY KEY,

type varchar (50) NOT NULL,

color varchar (25) NOT NULL,

location varchar(25) check (location in ('north', 'south', 'west', 'east', 'northeast', 'southeast', 'southwest', 'northwest')),

install_date date

);

We can see our new table by typing this:


Postgres=#\d

postgres=# \dt

Postgres=#\d

postgres=# \dt


postgres=# INSERT INTO playground (type, color, location, install_date) VALUES ('slide', 'blue', 'south', '2014-04-28');
INSERT 0 1
postgres=# INSERT INTO playground (type, color, location, install_date) VALUES ('swing', 'yellow', 'northwest', '2010-08-16');
INSERT 0 1

postgres=# INSERT INTO playground (type, color, location, install_date) VALUES ('slide', 'blue', 'south', '2014-04-28');

INSERT 0 1

postgres=# INSERT INTO playground (type, color, location, install_date) VALUES ('swing', 'yellow', 'northwest', '2010-08-16');

INSERT 0 1

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 1

This entry was posted in Hadoop on June 7, 2016 by Shiva Balena

To install the server locally use the command line and type


 sudo apt-get install postgresql postgresql-contrib

1 2	sudo apt-get install postgresql postgresql-contrib

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:


sudo -u postgres psql postgres

1 2	sudo -u postgres psql postgres

this connects as a role with same […]