Introduction to HBase for Hadoop

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Capture 15 HBase will come into picture, when Hadoop is stopped.

Capture 15 HBase is an open source, non-relational, distributed database which is built on top to HDFS.

Capture 15 Origins of H Base came from the Google Big Table and Big Tables can take up only structured data.

Capture 15 HBase will come into picture, where exactly Hadoop is left off i.e Hadoop’s primary storage mechanism by the means of HDFS does not suit for Random Reads and Random writes.

Capture 15 In order to provide real-time random reads and random writes, H Base will be used which is a column-oriented database.

Capture 15 In a typical RDBMS kind to databases like SQL, Mysql, Postage SQL, we cannot add or delete the columns at runtime.

Capture 15 In a web log table, we can add or delete the columns at runtime.

Capture 15 At that point of time, row oriented type of database will not fit correctly and end up with fired size not-column combination.

HBase Bases:-

Capture 15 The primary client interface to H Base Is the H Table class in the ora apache. Hadoop- hbase. client package.

 Capture 15 It provides the user with all the functionality which is needed to store and retrieve data from H Base as well as to delete obsolete values.

Capture 15 All operations that mutate data are guaranteed to be atomic on a per row basis.

Capture 15 It does not matter how many columns are written for the particular row, but all of them must be covered by this guarantee of atomics.

Capture 15 H Base is a column store data box where the entire accessing will be driven by column names row key intersection.

Empid Ename Esal
100 X 10000
101 Y 20000
102 z 15000

Column Store

Empid Ename Esal EDoj Epf
100 X 12000
101 Y 13000 2012-10-20 12345
102 Z
A 2012-10-01 2345


Capture 15 Zookeeper – Job Tracker, Task Tracker

Capture 15 H Master – Name Node

Capture 15Region Server – Data node.

Capture 15Regions – blocks.

Zookeeper:- H Base depends on Zookeeper and by default it manages a Zookeeper instance as the authority on cluster

HMaster:- Master Node:-

Capture 15 Assigns regions to region servers using Zookeeper

Capture 15 Handle load balancing

Capture 15 Not part of data path

Capture 15 Holds meta data and schema

Region Servers:-

 Capture 15 Handle Reads and writes.

Capture 15 Handle region splitting

Capture 15 ZK Capture 15 HM closely depends on Zookeeper and not on HM

Capture 15 It’s a onetime H Master job and all the data get stores in Zookeeper and H Master acts as a temporary Master.

Capture 15 H Base will store the information in the form of a column family names.

Ex:-                                Hadoop: Map Reduce Capture 15 Column Name

Column  Family            Hadoop: Pig Capture 15 Column Name

Name                              Hadoop: Hive Capture 15 Column Name

H Base Clients:- 

Capture 15 There are no. of client options for interacting with an H Base Cluster.

Capture 15 H Base, Like Hadoop is written in Java.

Capture 15 The primary client interface to HBase is the Hlabel cluss in the org. apache. hadoop. HBase. Client package.

Capture 15 The create a table, we need to first create an instance of H Base Admin and then ask it to create the table which is named test with a single column family named data.

Capture 15 Operating on a table, we will need an instance of org. apache. Hadoop. hbase. Client.

Capture 15 After creating an H Table, we then create instance of org. apache. Hadoop. H base. client

Capture 15 Next, we create an org. apache. Hadoop h base. Client. Get, and then use an org. apache. Hadoop. Habase. Client. Scan to see over the table against the just created table and print out the differences you find.

Map Reduce:-

Capture 15 H Base classes and utilities in the org. apache. Hadoop. Habase. Map reduce package facilitate using H Base as a source and/or sink in map reduce Jobs.

 Capture 15 The table input format class makes splits on region boundaries so maps are handed. A single region to work on.

Capture 15 The table output format will write the result of reduce into H Base.

Avro, REST and Thrift:-

Capture 15 HBase ships with Avro, REST and Thrift Interfaces.

Capture 15 These are useful when the interacting application is written in a language other than Java

Capture 15 In all cases, a Java server hosts an instance of the H Base client brokering application Avro. REST and Thrift requests in and out of the H Base cluster.

Capture 15 REST is to put up a star gate instance which is the name for the H Base REST service and start using the following command:

%h base- daemon-sh start rest.

Capture 15 This will start an instance by default on port 8080. And catch  any emissions by the server in log files under the H Base logs directory.

Capture 15 To stop the REST Server:

%h base- daemon-sh stop rest.

Thrift: Start a Thrift service by putting up a server to field Thrift clients by running the following:

%h base- daemon-sh start Thrift.

Capture 15 This will start the server instance by default on port 9090 and catch any emissions by the server in log files under the H Base logs directory.

Capture 15 The HBase thrift IDL can be found at

Src/main/resources/org/apache/hadoop/h base/thrift/h base. Thrift.

In the HBase source code.

Capture 15 To stop the thrift server, type:

%h base- daemon-sh stop Thrift.

Capture 15 To check the services for H Base.

# cd usr/lib/hadoop/conf

Cmd: /conf# ls master

o/p: masters

Cmd:/conf# cat master

o/p: local host

Cmd:/conf# ls slaves

o/p: slaves.

Cmd:/conf# cat slaves

o/p: local host

Capture 15 Region servers-slaves

HMaster-parent instance.

Capture 15 For H Base shell, change directory to h base bin dir

Cmd: # cd/user/lib/hbase/bin
/user/lib/hbase/bin#  shell


                           To show the tables.

Screenshot_1806 Here, if you got error means, parent instance services are not running, even though child instance services are running.

Screenshot_1806 If you want to start the parent instance services, first we have to kill the child instance services and then we have to start the parent.

/usr/lib/h base/bin # jps
#kill[peer process id]
#./start-h base. sh
# hbase shell.

Whir land tour of the data model:-

Screenshot_1806 Applications store data into labeled tables.

Screenshot_1806 Tables are made of rows and columns.

Screenshot_1806 Tables cells are the intersection of rows and columns which together coordinates as versioned.

 Screenshot_1806 By default, their version is a time stamp auto-assigned by H Base at the time of cell interaction.

Screenshot_1806 Table row keys are byte arrays theoretically. Any thing can serve a row key from strings to binary representations of long or even serialized data structures.

Screenshot_1806 Table rows are sorted by row key, the tables have the primary key and all table accesses are via the table primary key

Screenshot_1806 Row columns are grouped into column families. And all column family members have a common prefix

Screenshot_1806For example, the columns temperature: air and temperatures: dew- point are both members of the temperature column family writer as station identifier belongs to the station family.

 Screenshot_1806 The column family prefix must be composed of printable characters and the column family qualifier can be made available.


Screenshot_1806 Just as HDFS and Map Reduce are built of clients, slaves and a coordinating master.

  • Name Node and data node in HDFS and
  • Job tracker and task trackers in map reduce.

H Base modeled with an H Base master node orchestrating a cluster of one or more region server slaves.

Screenshot_1806 The H Base master is responsible for assigning regions to registered region servers and for recovering region servers and for recovering region server failures.

Screenshot_1806 The region servers carry zero or more regions and field client read/write requests.

Screenshot_1806 H Base persists data via the Hadoop file system API and since these are multiple implementations of the file system interface one for the local file system and one for the KRS file system, Amazon’s S3 and HDFS.

Screenshot_1806 The local file system is fine for experimenting with your initial H Base install.



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