Hive Query Language

What is Hive ?

Hive is a Query Language which is called as Hive QL and it works on Hadoop Distribute File System(HDFS), which we use it for generating Big Data warehouse Reports on Hadoop Distributed File System.

Where Hive is used?

In a real world Hive is mainly used for Big Data Analysis on huge data sets, ad-hoc querying on Hive command line interface for Generating reports for Big data analytic, if you know or if you had worked before on RDBMS SQL, Hive will be easy to understand because Big data can be stored as Tables on Hive Data Base and all of its table schema details are stored in Hive Meta store Big data Dash Board visualization and Reports can be created on hive table data by connecting to Hive Datawarehouse tables through Business intelligent Tools like Tableau, SAS..etc

How to use Hive on Hadoop?

let us  get started with Hive CLI,There are so many ways that we can use Hive, If you are using any of these Software  Distributions such as Cloudera/Hortonworks/MapR VM to launch Hive CLI, It is very easy we just need to type hive and press enter button.

 

Using geditor

You can open a gedit editor and type simple hive program i.e let us create a simple program and then we execute and see the output.

 

It will open up a Text editor where you can type hive queries and then you can issue the following command.

by specifying & at the end , once after opening the editor it allows us to use the same terminal session for some other purpose.

If you want to come out from the HIVE CLI command shell window, type quit on Hive CLI;

Tip: if you press shift + ctrl + N on existing command shell window, it will open up another new shell windo

 

HIVE Queries Execution using Tez

  • It is derived from Hindi Word, Which  means “Fast”.
  • SQL Engine that works with YARN to improve performance of Query Execution.
  • Tez minimizes the Map Operations and there by it decreases I/O Operations Overhead.
  • Tez Jobs are executed based on DAG (Direct A cyclic Graph)model.

How to enable the Tez Execution Engine?

we need to type the following statement on Hive Command Line Interface (CLI)

It always suggested to use Tez Execution engine for executing the HIVE QUERIES.

 

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