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Latest CouchBase Interview Questions and Answers

by Subashini, on Jul 20, 2022 7:52:15 PM

Latest CouchBase Interview Questions and Answers

Q1. What is the Couchbase server?


A Cloudbase server is basically nothing but a NoSQL database that is faster, elastic, as well as easy to use. It is regarded as one of the finest oriented-database software packages. The same is considered for the collective application that has multiple uses and is widely adopted in the modern-day approaches.

Q2. Is Couchbase an open sourse software?


Yes. Couchbase can be recognized as an open source software released under the Apache 2.0 license with an enterprise and community edition. Couchbase is a distributed multiform NoSQL file oriented database software package that is advanced for collective applications and open-source software.

Q3. What are the basic features of the Couchbase server?


The basic features of the Couchbase Server are

Fast – Couchbase is known for its quickness. Couchbase server facilitates the lower latency and highest throughput. The performance cost will be low and it is a remarkable sign .

Simple – Couchbase server is simple in terms of managing, installing, getting, expanding and using it. In a Couchbase server, it is not necessary to create and manage schemas, as a document database without normalizing and tuning of the database.

Elastic – The Couchbase server will distribute the data and I/O over virtual machines or commodity servers, thus it can make it easy to relate the optimal quantity of resources to the changing needs of an application. In couchbase server the nodes can be enhanced from 1 to 100 tons in a cluster and also can get reduced to sustain application performance.

Reliable – Couchbase server is stable and enterprise-ready software, so anyone can rely on mission critical applications.

Q4. How many functional blocks have involved in Couchbase server and brief about them?


There are two different functional blocks of Couchbase server and are

  1. Data Manager
  2. Cluster Manager

Data Manager : Data Manager is responsible for storing and extracting the data from applications in answer to data processing requirements. Data Manager will disclose 2 “memcapable” docks to the set of connections. 1 port guides non-vBucket aware client libraries and another one will guide to the vBucket aware client libraries. The most of Data manager code is written in C and C++ programming languages.

Cluster Manager : Cluster manager is made to look after the arrangement plus the performance of all nodes in a couchbase server cluster. The manger’s code will run on each lump in the cluster and selects one node for aggregation. The most of the Cluster Manager code is written in Erlang/OTP.

Q5. How can you say that a Couchbase Server is different from that of database software


Couchbase Server Other approaches
JSON documents can easily be stored JSON documents can be stored but there is a need to handle additional tasks for the same
Supports non- JSON documents too No support for non- JSON documents is available in most of the approaches
Binary data management is possible The same is not always possible
Vast support for API, REST and SQL is available No such support is available in all the cases


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Q6. What does N1Ql stand for?


It stands for the non-first normal form query language

Q7. Tell something about the Data Format in the Couchbase server?


The most basic unit of the data man manipulation in the Couchbase Server is a document. Documents get stored in the JSON document format without any predefined schemas.


Generally, it depends on the data and its type. Most of the documents and the files are present in the basic format and there are no predefined schemas. The files can be located in the JSON format.

Q8. Can you tell me something about the subsystems which are compatible with all the nodes in a network?


There are four subsystems that function on every node. They are as follows: 

  • Pattern Manager
  • Pulses
  • Single Ton Supervisor
  • Progression Monitor

Q9. Name the elements which are present in Couchbase Node?


Every Couchbase Node contains four elements. The elements have been mentioned below point-wise.

  • Index Service
  • Data Service
  • Cluster Manager component
  • Query Service

Q10. Name the programming language which Cluster Manager uses?


Erlang Programming Language

Q11. What are the good reasons for you to consider the Couchbase Server?


There are certainly good things about the Couchbase that makes it simply the best and there are tasks that can easily be accomplished through it. The very first thing is the maintenance which is very simple and users need not to worry about the same. Any sort of application even when they are different in features can be considered with it. The Couchbase is the server that simply makes sure consistency as well as control. In addition to this, flexibility and scalability are the other factors responsible. The users are free to keep up the pace easily with the multiple use cases. Also, the biggest features of couchbase are the users can deploy several types of databases very easily. 

Q12. How the task of locating a document in the Couchbase can be made easy according to you?


By considering the JSON format, this task can be made very easy and the best part is the things are done in a rightful manner only through this approach.

Q13. How many TCP ports are there to listen to the requests?


There are two TCP ports that are used to listen to requests.

  • Port 11210
  • Port 11211

The 11210 follows the cluster expansion rule while the Port 11211 follows the hashing algorithm

Q14. Tell something about the Cluster Manager in the Couchbase Server


It is mainly responsible for keeping an eye on the performance, as well as on the way the nodes are connected so a server. Depending on the tasks, there are certain types of methods through which the nodes can be connected to a server. It also makes sure that the code runs successfully on each lump. It also keeps a node reserved for the aggregation purpose.

Q15. What is the Role-based access control authentication approach in the Couchbase?


Role-Based Access Control is capable enough of ensuring cluster-resources to gbe exclusively accessed by customers with suitable privileges. Talking about privileges, these are gathered in Couchbase-defined groups. Each set or group is associated with an individual role. Users are ensured to assign one or many roles, and the privileges are granted which are associated with every role.


It simply makes sure that the cluster-resource can be used only by those users which are authorized to do so. In the server, there are privileges are defined into different sets and these sets are often dedicated to some or one specific node. One user can have multiple roles and they are often granted access for the privileges. 

Q16. What are the chances of a Couchbase server failure and what are the factors that can be held responsible for the same?


The chances for the failure of a server are very less and the best thing is an overall number of failures reported about Couchbase are very less. Some of the factors that can cause this issue are listed below

  • Failure of the power
  • No maintenance of the server
  • Presence of inauspicious data
  • Improper Integration
  • Hacking related issues
  • Slow bandwidth
  • Improper allocation of the same

Q17. What do you mean by the Cross Datacenter Replication?


XDCR or Cross Datacenter Replication helps in providing a seamless mode to replicate data from one set to another. Cross Datacenter Replication involves replicating active data to N+1 Server clusters, or even external apps such as Spark, Elastic, Storm, and so forth. The sets are used for various geographically diverse data centers. They are used either for bringing data closer to customers for fast-paced data access or the recovery of any disaster.


When it comes to replicating the data from one cluster to another, the cross datacenter replication is considered. When the data centers are geographically different or when they are diverse, this approach is also considered for eliminating various problems from the domain.

Q18. What sort of technical specialty is required to handle the Couchbase or to work with the same?


Basic knowledge about the network and computing is mandatory. Network communication basics, installation of the network, and maintenance of the same are the other skills that are helpful. The other skills depend on the task assigned to you.

Q19. What are the needs that the Couchbase Servers can easily satisfy?


There are certain needs that the Couchbase server can easily fulfill. The first is assuring a unified programming Interface can handle queries and searches. In addition to this, mobile and Internet of Things demands can easily be fulfilled through this. Also, various tasks like core database engine, analytics, SQL integrations, scale-out architecture, core database engine, as well as memory first architecture can easily be fulfilled.

Q20. How Couchbase Data Platforms are useful in building the applications that are scalable?


It provides a uniform, simple, quick, and in fact a powerful application development API that always makes sure of applications that are good enough to be considered. As it can easily be deployed, the application needs can be fulfilled in a very short span of time. Intelligence can easily be added to the applications, time delays can be avoided and the overall downtime can be reduced upto a great extent.

Q21. What are the capabilities of a core database engine?


There are certain abilities of the same which is very useful when it comes to managing the data of the applications. In addition to this, it is also good enough to be trusted for the document applications. The users can easily deploy its architecture anywhere they want. Other capabilities include caching of data, data persistence, as well as database management.

Q22. Can nodes be added easily in the Couchbase or there are some special conditions that need to be fulfilled?


It is possible to add nodes without meeting the complex criteria in Couhbase.

Q23. How will you define Couchbase Server?


Couchbase Server is a fast, seamless, NoSQL database which was initially termed as Membase. It is a software package that is technologically advanced multi-model NoSQL, and is file-oriented. It has been proposed for interacting through web applications.

Q24. Is Couchbase amultiform NoSQL file oriented database software package?


The answer to this question is yes, Couchbase is a distributed multiform NoSQL file-oriented database software package. Couchbase is generally defined as open-source software that was released under Apache license that consisted of a community and enterprise edition.

Q25. Why is Couchbase more advanced than MongoDB?


MongoDB provides multi-step scalability, whereas, Couchbase offers a seamless scalability property. The reason why Couchbase is more advanced than MongoDB is due to the consistency. Couchbase arrives with a high consistency power; while on the contrary, MongoDB offers a low consistency power. Plus, Couchbase’s uptime is always up. While on the other hand, MongoDB’s uptime needs a bit of maintenance.

Q26. What is the difference between Couchbase and CouchDB?


Couchbase is capable enough of storing key-values as well as credentials. Thus, it can store data like binary data, JSON documents, and many more.Couchbase server makes use of a binary Memcached protocol to perform the high-end functionalities as well as REST API’s SQL in order to view the queries.

Apache CouchDB, on the contrary, is capable of storing JSON documents. It also provides facilities to attach non-JSON files to the JSON documents.

Q27. What are the important advantages of including Couchbase and CouchDB into a single product?


First and foremost, Couchbase server happens to be a super-fast and highly scalable key-value store which is known for its high-end scalability as well as performance. Secondly, CouchDB, on the contrary, is an excellent document database that comes with powerful querying as well as indexing capabilities. So combining the aforementioned two would be beneficial. Not only will it create a high-end performance, but also highly elastic NoSQL database that will scale out the linearly. At the same time, it will also provide indexing, querying as well as other document-oriented features. Hence including Couchbase and CouchDB will be beneficial.

Q28. Briefly explain the four subsystems that function on each node


The four subsystems that function on each node are Pulses, Progression Monitor, Worldwide Singleton Supervisor, and Pattern Manager. The explanations have been mentioned right below.

  • Pulses: A set of words are exchanged by the Watchdog developers regularly. The exchanging process is carried forward with the currently chosen cluster head in order to provide well-being revises.
  • Worldwide Singleton Supervisor: Worldwide Singleton Supervisor, is one of the subsystems which is tasked to select the cluster heads only in case the previously voted head stops.
  • Progression Monitor: Progression Monitor is that subsystem that helps in monitoring in carrying out the limited executive. Thereby, it resumes unsuccessful procedures as per the need. Finally, it contributes state data to those beating piece.
  • The Pattern Manager: Each node in the set features a specific pattern, for example,the intention map or vBucket map, so on and so forth. Pattern Manager receives, monitors, and processes the local configuration.

Q29. Can Couchbase speed up the accession to any database document by catching it in memory automatically?


The answer is, definitely, Couchbase has the capability of speeding up access to any database document by automatically catching it in the memory.

Q30. How does Couchbase speed up the accession to a particular database document automatically via memory?


Couchbase Server 2.0 comes from a host of experiences with memcached. The accession to the documents is gone through the integrated RAM caching layer that has been made up of memcached. This helps in providing low and predictable latency under immensely heavy loads.

Q31. What do you mean by Storage Engine in Couchbase?


Couchbase Server features a design philosophy of tail-append storage. It is immune to data corruption, sudden power loss, or even OOM killers. Data happens to be written in the data file that enables Couchbase to mostly do sequential write-ups for an update. Also, it provides optimized and enhanced access patterns for disk I/O.

Q32. What Is Document in Couchbase?


In Couchbase, a document usually refers to an entry in the database. A document consists of an ID that happens to be unique by nature. Its value contains the real application data. Documents are stored on the server as JSON. While JSON is a structured format that happens to be a structured format, it can be searched and accordingly get queried by following the below-mentioned command.

“type”: “product”,
“sku”: “CBSRV45DP”,
“msrp”: [5.49, “USD”],
“ctime”: “092011”,
“mfg”: “couchbase”,
“tags”: [“server”, “database”, “couchbase”, “nosql”, “fast”, “json”, “awesome”]

Q33. What Is N1QL?


N1QL happens to be a query language or the non-first usual form of the query language. It is purposed to manipulate JSON data in the Couchbase server. Some of its statements to operate the JSON data are as follows:

  4. MERGE

Q34. What do you mean by Object-managed Cache in the Couchbase Server?


Couchbase Server comprises an object-managed, built-in, and multi-threaded cache. The cache is capable of implementing APIs that are memcached compatible, for example, append, prepend, set, get, and more.

Q35. Explain the role of Data Structures in the Couchbase server?


In Couchbase, Data structures are similar to those included in javascript.Map is a key-value structure that is similar to a JavaScript Object. In Map, a value is accessed by employing the key string. One can place the values in the very beginning or at the end.

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