Cassandra Interview questions
(1)Continuous uptime and low latency is achieved in NoSQL systems as compared to traditional relational databases.
Yes
No
Ans:Yes
(2)What is meant by 'Active everywhere design'?
There is no single point of failure
All nodes communicate with each other
All nodes are equal
All nodes can be written to and read from
Ans:All nodes can be written to and read from
(3)Cassandra is a __________ architecture.
3-teir
peer-to-peer
None of the options mentioned
Master-slave
Ans:peer-to-peer
(4)Cassandra is not suitable for IoT applications.
False
True
Ans:False
(5)Which among the following is a NoSQL db?
MongoDB
Couchbase
Cassandra
All of the options mentioned
Ans:All of the options mentioned
(6)Which of the following statements about NoSQL databases is true?
Do not provide horizontal scalability
Support unstructured data
Do not support Query Language
All of the options mentioned
Ans:Support unstructured data
(7)Which Linux flavour can be used for Cassandra Installation?
CentOS
Debian
Red Hat
All of the options mentioned
Ans:All of the options mentioned
(8)Which command can be used to list all available commands/operations in Cassandra?
CAPTURE
SHOW
HELP
EXPAND
Ans:HELP
(9)SSTable resides in memory.
False
True
Ans:False
(10)Which type of data model does Cassandra use?
Key-value data model
Both key-value and tabular data models
Tabular data model
Multivalue model
Ans:Both key-value and tabular data models
(11)Java instance should be running in the machine inorder to setup Cassandra.
No, you do not require
It's optional
Yes, java must be running in the machine
None of the options mentioned
Ans:Yes, java must be running in the machine
(12)Cluster can have multiple seed nodes.
True
False
Ans:True
(13)A bloom filter can return __________.
Bloom-filter does not help in locating data
A false negative
the exact location of the requested data
A false positive
Ans:A false negative
(14)What are ‘seed nodes’ in Apache Cassandra?
There must be at least one seed node in a cluster
One may configure more than one seed node for added redundancy
They allow the instance to find the cluster on the very first startup
All of the options mentioned
When a node first starts, it contacts a seed node to bootstrap the gossip communication process.
Ans:All of the options mentioned
(15)What is the default partitioner in Apache Cassandra cluster?
Murmur3Partitioner
ByteOrderedPartitioner
HashPartitioner
RandomPartitioner
Ans:Murmur3Partitioner
(16)Cassandra attaches a timestamp to each version of the record and uses this to merge records .
No, Merge is not supported by cassandra.
Yes
No
Ans:Yes
(17)Row cache is an in-memory cache, which stores recently read rows.
True
False
Answe:-True
(18)The simplest and the fastest read path is when the record is present in the __________.
Commit log
Row Cache
Partition Key cache
Bloom filter
Ans:Row Cache
(19)Authorization capabilities for Cassandra use the familiar__________ security paradigm to manage object permissions.
ROLLBACK
COMMIT
GRANT
None of the options mentioned
Ans:GRANT
(20)To be able to read data from compressed blocks, Cassandra consults __________.
Row cache alone
Compression offsets
commit log
compressed key cache
Ans:Compression offsets
(21)Pick the correct statements.
Row cache is an in-memory cache.
Key Cache maps recently read partition keys to specific SSTable offset.
Compaction offsets keeps the offset mapping information for compressed blocks.
Partition Indexes are sorted partition keys mapped to their SSTable offsets.
All of the options mentioned
Ans:All of the options mentioned
(22)What is C-A-P, in CAP theorem?
Concurrency 2) Atomicity and 3) Partition tolerance
Consistency 2) Availability and 3) Partition tolerance
Consistency 2) Atomicity and 3) Partition tolerance
Concurrency 2) Availability and 3) Primary indexing
Ans:Consistency 2) Availability and 3) Partition tolerance
(23)Is Timestamp an optional field in Column?
False
True
Ans:True
(24)Pick the correct statement.
Under each column-family, there can be multiple rows.
All the options mentioned
A cluster can have more than one key-space.
There can be one or more column-family under a key-space.
Ans:All the options mentioned
(25)Pick the correct statement.
Each keyspace has at least one and often many column families.
None of the options mentioned
Any column cannot be added to a column family after creation.
Column families do not represent the structure of your data.
Ans:Each keyspace has at least one and often many column families.
(26)Which among the following is not a Replica Placement strategy?
Simple Strategy
Network Topology Strategy
None of the options mentioned
Old Network Topology Strategy
Ans:None of the options mentioned
(27)Keyspace is analogous to __________ in realtional world.
columns
database
data types
records
Ans:database
(28)Which among the following is the right syntax for 'Using a Keyspace'?
REUSE
USE CURRENT
USE
USE
Ans:USE
(29)Pick the correct statement.
Primary key is a column.
Primary key is used to uniquely identify a row.
Primary key can be composed of more than one column.
Primary key is mandatory in creating a table.
All of the options mentioned
Ans:All of the options mentioned
(30)Which of the following statements is true about CQL?
CQL does not support joins.
CQL model is close to SQL.
CQL supports prepared statements.
All of the options mentioned
CQL supports joins.
Ans:All of the options mentioned
(31)What is the primary language for communicating with the Apache Cassandra™ database?
CQL
None of the options mentioned
SQL
HQL
Ans:CQL
(32)Which directory contains Cassandra configuration files?
lib
interface
bin
conf
Ans:conf
(33)Defining a primary key is mandatory while creating a table.
True
False
Answer:True
(34)Which Linux flavour can be used for Cassandra Installation?
Red Hat
All of the options mentioned
CentOS
Debian
Ans:All of the options mentioned
(35)What can also be attributed as wide-row in Apache Cassandra?
Foreign Key
Clustering Key
Primary Key
Compound Key
Ans:Compound Key
(36)Which collection type is used to maintain uniqueness of data structure?
Map
Heap
List
Set
Ans:Set
(37)CQL features include __________.
All of the options mentioned
Nested user-defined types
Timestamps precise to the millisecond
Configurable counter cache
Ans:All of the options mentioned
(38)How does Cassandra store data?
By dividing all data evenly around a cluster of nodes, which can be visualized as a ring.
By storing all data in the master node and directing them to slaves as per request.
There is no specified scheme set for data storage.
By storing data in slave nodes and storing its offsets in master node.
Ans:By dividing all data evenly around a cluster of nodes, which can be visualized as a ring.
(39)NoSQL db - Cassandra is of type __________.
Graph databases
Document databases
Wide-column stores
Key-value databases
Ans:Wide-column stores
(40)Which of the following is not part of SSTable?
Bloom filter
Data
Memtable
Index
Ans:Memtable
(41)What is the use of commit log?
Monitoring
Crash-recovery
Performance Improvement
Logging
Ans:Crash-recovery
(42)What is the primary language for communicating with the Apache Cassandra database?
Cassandra do not support query language.
HQL
SQL
CQL
Ans:CQL
(43)In cassandra consistency is achieved through consistency tuning mechanisms.
False
True
Ans:True
(44)Minimum JVM version required for Cassandra is __________.
1.3
1.6
1.4
1.5
Ans:1.6
(45)__________ is a collection of related nodes.
Data center
Ring
Node
Cluster
Ans:Data center
(46)Cassandra supports ACID transactions?
False
True
Ans:False
(47)Which OS does Cassandra support?
Both Windows and Linux
None of the options mentioned
Linux
Windows
Ans:Both Windows and Linux
(48)Primary key is a column that is used to uniquely identify a row.
False
True
Ans:True
(49)What can be used to monitor clock drifts?
SSH
NTP
HTTP
JMX
Ans:NTP
(50)__________ can be configured per table for non-QUORUM consistency levels.
Write repair
Write damage
Read damage
Read repair
Ans:Read repair
(51)Replication can be configured to work across __________.
Single Data center
Single Ring
single cloud availability zones
one or more Data Centers
Ans:one or more Data Centers
(52)Which technique is used for error correction for every compressed block?
Parity bit
CRC
Hashing
ECC
Ans:CRC
(53)Cassandra will keep appending the records into the Commit Log and then to the memtable.
False
True
Ans:True
(54)What percentage is the default threshold of memory used for flushing of the largest Memtables?
75
80
50
65
Ans:65
(55)CQL features include __________.
Nested user-defined types
All of the options mentioned
Timestamps precise to the millisecond
Configurable counter cache
Ans:All of the options mentioned
(56)User accounts may be altered and dropped using the __________ Query Language.
Cassandra
Sqoop
None of the options mentioned
Hive
Ans:Cassandra
(57)Cassandra promotes __________ operation.
Read-after-write
Read-before-read
Read-before-write
Write-after-write
Ans:Read-before-write
(58)Which directory contains Cassandra configuration files?
bin
interface
conf
lib
Ans:conf
(59)Which among the following is not a performance measurement tool?
iostat
cmstat
None
dstat
Ans:None
(60)How does Murmur3Partitioner work?
None of the options mentioned
Order keys as per byte values
Order values
Fast hash-based partitioner
Ans:Fast hash-based partitioner
(61)Partitioners supported by Cassandra are __________.
All of the options mentioned
ByteOrderedPartitioner
Murmur3Partitioner
RandomPartitioner
Ans:All of the options mentioned
(62)A cluster is __________.
A collection of data centers
A collection of nodes
None of the options mentioned
A collection of connected nodes
Ans:A collection of data centers
(63)Which of the following statements is true?
Cassandra has a "masterless" architecture, where all nodes are the same.
All of the options mentioned
Cassandra provides customizable replication, storing redundant copies of data across nodes that participate in a Cassandra ring.
Cassandra delivers continuous availability, linear scalability, and operational simplicity across many commodity servers.
Ans:All of the options mentioned
(64)NoSQL db - Cassandra is of type __________.
Key-value databases
Wide-column stores
Graph databases
Document databases
Ans:Wide-column stores
(65)Which collection type in Cassandra is dictionary like object?
Set
Heap
Map
List
Ans:Map
(66)Which technique is used for error correction for every compressed block?
Parity bit
ECC
Hashing
CRC
Ans:CRC
(67)What is the critical bottleneck faced during creation of data model?
Storage capacity of node
Hot Spots
Processing capacity of node
Inter-node communication
Ans:Hot Spots
(68)Each flush of the memtable results in the creation of __________.
Sstable
flush record
Commit log
Partition
Ans:Sstable
(69)User accounts may be altered and dropped using the __________ Query Language.
Hive
Cassandra
None of the options mentioned
Sqoop
Ans:Cassandra
(70)There are __________ types of read requests that a coordinator can send to a replica.
2
3
4
6
Ans:3
(71)The process of turning a Memtable into a SSTable is called __________.
Spilling
Compression
Compaction
Flushing
Ans:Flushing
(72)In Cassandra, data is first written to __________.
Memtable
SStable
Commit Log and Memtable
Commit log
Commit log and Sstable
Ans:Commit Log and Memtable
