Top 20 HBase Interview Questions Answers

Interview Question for HBase

 

1. What are the key components of HBase?

The Four major key components of HBase are

  1. HMaster
  2. HRegions
  3. HRegionserver
  4. Zookeeper.

2. When should you use Hbase?

The HBase should be used when the big data application has,

  1. A variable schema
  2. When data is stored in the form of collections.
  3. If the application demands key-based access to data while retrieving.

3. What is Row Key?

The unique identifier in every row of hbase is know as  Row Key.

* The logical grouping of cells is done by using Row Key.

* It is internally treated as a byte array.

4. What is the main difference between HDFS and HBase?

The main differences are,

  1. HDFS does not provides fast lookup records in a file.
  2. Hbase provides fast lookup records for large table.

5. Why filters are useful in Apache HBase?

It allows to perform server-side filtering when accessing HBase over Thrift or HBase shell.

6. Explain about HBase in brief?

HBase is a column oriented distributed database residing within the hadoop environment. It stores bulk data range from terabytes to petabytes. HBase is scalable, distributed big data storage on top of the hadoop eco-system. It has some special features compared with traditional relational database models.

7. State main differences between HBase and RDBMS?

  • The RDBMS is a row oriented database having a fixed schema.
  • The HBase is a column oriented storage having a flexible schema.

8. Name some column oriented databases other than HBase?

Some of the popular column oriented databases are Cassandra, MongoDB and CouchDB.

9. which type of partition is provided by HBase?

HBase provide automatic partitions.

10. Which command is used to show the current user in HBase?

The “whoami” command is used to show HBase user.

11. What is Thrift?

Thrift is written in C++ used to provides schema compilers for many programming languages like Java, C++, Perl, PHP, Python, and Ruby etc.

12. What is a catalog table in HBase?

Catalog table is a metadata information repository in hbase. 

13. What is the use of ZooKeeper in Hbase?

The ZooKeeper is used for,

  1. It maintain the configuration information.
  2. Communicate between region servers and clients.
  3. It also provides distributed synchronization.
  4. It maintain the server state inside the cluster by communicating through sessions.
  5. Zookeeper checks the server is alive and available using continuous heartbeat from every Region Server along with HMaster Server.
  6. Provides server failure notifications so that, recovery measures can be executed.

14. What is the use of get() method?

The get() method is used to read the data from the table.

15. Mention the different catalog tables in HBase?

The two important catalog tables in HBase are,

  1. ROOT table- It tracks information about META table.
  2. META table- It stores all the regions information in the system.

16. Which operating systems are supported in HBase?

HBase supports those OS which supports java like,

  1. windows
  2. Linux.

17. How many filters are available in Apache HBase?

There are 18 filters supported in hbase they are,

  1. ColumnPrefixFilter
  2. TimestampsFilter
  3. PageFilter
  4. MultipleColumnPrefixFilter
  5. FamilyFilter
  6. ColumnPaginationFilter
  7. SingleColumnValueFilter
  8. RowFilter
  9. QualifierFilter
  10. ColumnRangeFilter
  11. ValueFilter
  12. PrefixFilter
  13. SingleColumnValueExcludeFilter
  14. ColumnCountGetFilter
  15. InclusiveStopFilter
  16. DependentColumnFilter
  17. FirstKeyOnlyFilter
  18. KeyOnlyFilter.

18. How to delete the table with the shell?

In order to delete table first we need to disable it then delete it.

Example

hbase> disable ‘beyondemp’

hbase> drop ‘beyondemp’

19. What is Hfile?

The columns in a column family are stored together in the same low-level storage file is called as Hfile.

20. How to connect to Hbase?

Using a Java API connection is established through Hbase Shell.