50+ Cassandra Interview Questions

50+ Cassandra Interview Questions

Cassandra Interview Questions

1) Explain Cassandra. 

Cassandra is a prominent NOSQL database the board framework used to deal with vast measure of information. It is free and open source disseminated database that gives high accessibility with no disappointment.

2) In which language Cassandra is composed? 

Cassandra is written in Java. It is initially planned by Facebook comprising of adaptable blueprints. It is profoundly versatile for enormous information.

3) Who was the first creator of Cassandra? 

The first creators of Cassandra are Avinash Lakshman and Prashant Malik. It was at first created at Facebook to control the Facebook inbox look highlight.

4) Which inquiry language is utilized in Cassandra database? 

Cassandra presented its very own Cassandra Query Language (CQL). CQL is a basic interface for getting to Cassandra, as an option in contrast to the customary Structured Query Language (SQL).

5) What are the advantages/focal points of Cassandra? 

Cassandra conveys constant execution streamlining crafted by Developers, Administrators, Data Analysts and Software Engineers.

It gives extensible versatility and can be effectively scaled up and downsized according to the prerequisites.

Information can be repeated to a few hubs for adaptation to non-critical failure.

Being a disseminated administration framework, there is no single purpose of disappointment.

Each hub in a group contains distinctive information and ready to serve any ask for.

6) Where Cassandra stores its information? 

Cassandra stores its information in the information word reference.

7) What was the plan objective of Cassandra? 

The principle plan objective of Cassandra was to deal with huge information outstanding tasks at hand over numerous hubs without a solitary purpose of disappointment.

8) what number kinds of NoSQL databases? Give a few precedents. 

There are for the most part 4 kinds of NoSQL databases:

Archive store types ( MongoDB and CouchDB)

Key-Value store types ( Redis and Volgemort)

Segment store types ( Cassandra)

Chart store types ( Neo4j and Giraph)

9) Mention some critical parts of Cassandra information models? 

These are some key parts of Cassandra information show: -

Table( accumulation of segments)




10) What are different segments of Cassandra? 

Some different segments of Cassandra are:


Server farm

Submit log



Sprout Filter

11) What is keyspace in Cassandra? 

In Cassandra, a keyspace is a namespace that decides information replication on hubs. A bunch contains of one keyspace per hub.

12) What are the distinctive composite keys in Cassandra? 

In Cassandra, composite keys are utilized to characterize key or a segment name with a connection of information of various kind. There are two kinds of Composite key in Cassandra:

Line Key

Section Name

13) What is information replication in Cassandra? 

Information replication is an electronic duplicating of information from a database in one PC or server to a database in another with the goal that all clients can have a similar dimension of data. Cassandra stores copies on various hubs to guarantee unwavering quality and adaptation to internal failure. The replication methodology chooses the hubs where imitations are put.

14) What is hub in Cassandra? 

In Cassandra, hub is where information is put away.

15) What do you mean by server farm in Cassandra? 

Server farm is a finished information of bunches.

16) What do you mean by submit sign in Cassandra? 

In Cassandra, submit log is an accident recuperation component. Each compose activity is composed to the submit log.

17) What do you mean by section family in Cassandra? 

Section family is a table in RDMS that contains an arranged accumulation of columns.

18) What do you mean by consistency in Cassandra? 

Consistency in Cassandra indicates how to synchronize and forward-thinking a column of Cassandra information and its reproductions.

19) what number sorts of tunable consistency are upheld in Cassandra? 

It underpins two textures: Eventual Consistency and Strong Consistency.

The inevitable consistency is utilized when no new updates are made on a given information thing, all gets to restore the last refreshed esteem in the long run. Frameworks with inevitable consistency are known to have accomplished imitation combination.

Cassandra underpins the accompanying conditions for solid consistency:

R + W > N


N: Number of imitations

W: Number of hubs that need to concur for an effective compose

R: Number of hubs that need to concur for an effective read

20) What is tunable consistency in Cassandra? 

Tunable Consistency is a sensational normal for Cassandra which settles on it a well known decision. Consistency alludes to the exceptional and synchronized information pushes on the entirety of their copies. Cassandra's Tunable Consistency encourages clients to choose the consistency level most appropriate for their utilization cases.

21) What is the sentence structure to make keyspace in Cassandra? 


22) What is a section family in Cassandra? 

In Cassandra, a gathering of lines is alluded as "section family".

23) How does Cassandra perform compose work? 

Cassandra plays out the compose work by applying two submits:

First submit is connected on plate and after that second focus on an in-memory structure known as memtable.

At the point when the both submits are connected effectively, the compose is accomplished.

Composes are written in the table structure as SSTable (arranged string table).

24) What is memtable? 

Memtable is in-memory/compose back reserve space containing content in key and section position. In memtable, information is arranged by key, and each ColumnFamily has an unmistakable memtable that recovers segment information by means of key. It stores the composes until it is full, and afterward flushed out.

25) What is SSTable? 

SSTable is a short type of 'Arranged String Table'. It alludes to an essential information document in Cassandra and acknowledges ordinary composed memtables. They are put away on plate and exist for every Cassandra table.

26) How the SSTable is not the same as other social tables? 

SStables don't permit any further expansion and expulsion of information things once composed. For each SSTable, Cassandra makes three separate records like segment file, parcel rundown and a blossom channel.

27) What are the administration instruments in Cassandra? 

DataStaxOpsCenter: It is a web based administration and checking answer for Cassandra group and DataStax. It is allowed to download and incorporates an extra Edition of OpsCenter.

SPM: SPM principally controls Cassandra measurements and different OS and JVM measurements. It likewise screens Hadoop, Spark, Solr, Storm, zookeeper and other Big Data stages other than Cassandra.

28) Mention some imperative highlights of SPM in Cassandra? 

The principle highlights of SPM are:

Connection of occasions and measurements

Disseminated exchange following

Making constant charts with zooming

Location and heartbeat alarming

29) What is bunch in Cassandra? 

In Cassandra, the bunch is a furthest compartment for keyspaces that organizes the hubs in a ring group and doles out information to them. These hubs have a copy which assumes responsibility if there should be an occurrence of information dealing with disappointment.

30) What is the job of ALTER KEYSPACE? 

Modify KEYSPACE is utilized to change the estimation of DURABLE_WRITES with its related properties.

31) What do you mean by Cassandra-Cqlsh? 

Cqlsh is a Cassandra inquiry language shell used to execute the directions of CQL (Cassandra question language).

32) What are the contrasts between a hub, a bunch, and datacenter in Cassandra? 

Hub: A hub is a solitary machine running Cassandra.

Bunch: A group is a gathering of hubs that contains comparable kinds of information together.

Datacenter: A datacenter is a valuable segment when serving clients in various land regions. Diverse hubs of a bunch can be assembled into various server farms.

33) What is the utilization of Cassandra CQL accumulation? 

Cassandra CQL accumulation is utilized to gather the information and store it in a segment where every gathering speaks to a similar kind of information. CQL comprise of three sorts of sorts:

SET: It is a gathering of unordered rundown of one of a kind components.

Show: It is a gathering of components organized in a request and can contain copy esteems.

Guide: It is a gathering of one of a kind components in a type of key-esteem pair.

34) What is the utilization of Bloom Filter in Cassandra? 

On a solicitation of an information, before doing any circle I/O Bloom channel checks whether the mentioned information exist in the line of SSTable.

35) How does Cassandra erase information? 

In Cassandra, to erase a line, it is required to relate the estimation of section to Tombstone (where Tombstone is an extraordinary esteem).

36) What is SuperColumn in Cassandra? 

In Cassandra, SuperColumn is an interesting component containing comparative accumulation of information. They are really key-esteem sets with qualities as segments.

37) What is the contrast among Column and SuperColumn? 

Contrast among Column and SuperColumn:

The qualities in sections are string while the qualities in SuperColumn are Map of Columns with various information types.

In contrast to Columns, Super Columns don't contain the third segment of timestamp.

38) What is Hadoop, HBase, Hive and Cassandra? Determine similitudes and contrasts among them. 

Hadoop, HBase, Hive and Cassandra all are Apache items.

Apache Hadoop bolsters record stockpiling, framework register handling by means of Map decrease. Apache Hive is a SQL like interface on the highest point of Haddop. Apache HBase pursues segment family stockpiling fabricated like Big Table. Apache Cassandra likewise pursues segment family stockpiling constructed like Big Table with Dynamo topology and consistency.

39) What is the utilization of "void close()" strategy? 

In Cassandra, the void close() technique is utilized to close the present session occasion.

40) Which direction is utilized to begin the cqlsh brief? 

The cqlsh direction is utilized to begin the cqlsh brief.

41) What is the utilization of "cqlsh-rendition" order? 

The "cqlsh-rendition" order is utilized to give the adaptation of the cqlsh you are utilizing.

42) Does Cassandra deal with Windows? 

Indeed. Cassandra is perfect on Windows and works really well. Presently its Linux and Window perfect adaptation are accessible.

44) What do you mean by Thrift in Cassandra?
Thrift is the name of RPC client which is used to communicate with the Cassandra Server.

45) What is Hector in Cassandra?
Hector was one of the early Cassandra clients. It is an open source project written in Java using the MIT license.