hbase (1)1.What are the different commands used in Hbase operations?
There are 5 atomic commands which carry out different operations by Hbase.

Get, Put, Delete, Scan and Increment.

2.How to connect to Hbase?
A connection to Hbase is established through Hbase Shell which is a Java API.

3.What is the role of Master server in Hbase?
The Master server assigns regions to region servers and handles load balancing in the cluster.

4.What is the role of Zookeeper in Hbase?
The zookeeper maintains configuration information, provides distributed synchronization, and also maintains the communication between clients and region servers.

5.When do we need to disable a table in Hbase?
In Hbase a table is disabled to allow it to be modified or change its settings. .When a table is disabled it cannot be accessed through the scan command.

6.Give a command to check if a table is disabled.
Hbase > is_disabled “table name”

7.What does the following table do?
hbase > disable_all ‘p.*’

The command will disable all the table starting with the letter p

8.What are the different types of filters used in Hbase?
Filters are used to get specific data form a Hbase table rather than all the records.

They are of the following types.

Column Value Filter
Column Value comparators
KeyValue Metadata filters.
RowKey filters.

9.Name three disadvantages Hbase has as compared to RDBMS?
Hbase does not have in-built authentication/permission mechanism

The indexes can be created only on a key column, but in RDBMS it can be done in any column.

With one HMaster node there is a single point of failure.

10.What are catalog tables in Hbase?
The catalog tables in Hbase maintain the metadata information. They are named as −ROOT− and .META. The −RROT− table stores information about location of .META> table and the .META> table holds information about all regions and their locations.

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