Couchbase Interview Questions And Answers For Experienced

Couchbase Interview Questions And Answers. Here Coding compiler sharing a list of 25 interview questions on Couchbase. These Couchbase questions were asked in various Couchbase interviews by top MNC companies and prepared by Couchbase experts. This list of Couchbase server interview questions will help you to crack your next Couchbase job interview. All the best for your future and happy learning.

Couchbase Interview Questions

  1. What is Couchbase Server?
  2. Couchbase node consists of which elements?
  3. What is Cluster manager in Couchbase?
  4. Cluster manager uses which programming language?
  5. What are Replication and fail-over?
  6. What is Data manager in Couchbase?
  7. What is Data format in Couchbase?
  8. What is Object-managed cache in Couchbase server?
  9. What is Storage engine in Couchbase server?
  10. What is N1QL?

Couchbase Interview Questions And Answer

1) What is Couchbase Server?

A) Couchbase Server, originally known as Membase, is an open-source, distributed multi-model NoSQL document-oriented database software package that is optimized for interactive applications.

2) Couchbase node consists of which elements?

A) Every Couchbase node consists of a data service, index service, query service, and cluster manager component.

3) What is Cluster manager in Couchbase?

A) The cluster manager supervises the configuration and behavior of all the servers in a Couchbase cluster. It configures and supervises inter-node behavior like managing replication streams and re-balancing operations. It also provides metric aggregation and consensus functions for the cluster, and a RESTful cluster management interface.

4) Cluster manager uses which programming language?

A) The cluster manager uses the Erlang programming language and the Open Telecom Platform.

5) Replication and fail-over?

A) Data replication within the nodes of a cluster can be controlled with several parameters. Support was added for replication between different data centers.

6) What is Data manager in Couchbase?

A) The data manager stores and retries documents in response to data operations from applications. It asynchronously writes data to disk after acknowledging to the client. Applications can optionally ensure data is written to more than one server or to disk before acknowledging a write to the client.

7) What is Data format in Couchbase?

A) A document is the most basic unit of data manipulation in Couchbase Server. Documents are stored in JSON document format with no predefined schemas.

8) What is Object-managed cache in Couchbase server?

A) Couchbase Server includes a built-in multi-threaded object-managed cache that implements memcached compatible APIs such as get, set, delete, append, prepend etc.

9) What is Storage engine in Couchbase server?

A) Couchbase Server has a tail-append storage design that is immune to data corruption, OOM killers or sudden loss of power. Data is written to the data file in an append-only manner, which enables Couchbase to do mostly sequential writes for update, and provide an optimized access patterns for disk I/O.

10) What is N1QL?

A) A query language called the non-first normal form query language, N1QL, is used for manipulating the JSON data in Couchbase. It has SELECT, INSERT, UPDATE, DELETE, MERGE statements to operate on JSON data.

Couchbase Server Interview Questions

11) Why do we use Couchbase server?

A) Couchbase is designed for consistency and control, they lack agility, flexibility, and scalability. To execute multiple use cases, organizations are forced to deploy multiple types of databases

12) What are the benefits of using Couchbase?

A) It exposes a fast key-value store with managed cache for sub-millisecond data operations, purpose-built indexers for fast queries and a powerful query engine for executing SQL-like queries. For mobile and Internet of Things, environments Couchbase also runs natively on-device and manages synchronization to the server.

13) What is Full-text Search?

A) Built-in full-text search makes it simple for developers to add intelligence to apps. Full text indexes are automatically managed within the Couchbase cluster, avoiding the time delay, overhead, and complexity of managing a separate full-text search product and infrastructure.

14) What is Analytics in Couchbase?

A) Couchbase Analytics provides powerful parallel query processing. Designed to efficiently execute complex, long-running queries that contain complex joins, set, aggregation, and grouping operations.

Couchbase Interview Questions # 15) Explain about the core Database Engine in Couchbase?

A) The core database engine provides the fundamental capabilities for document management and indexing. Based on a memory-first, async everywhere architecture, this includes core capabilities of the database engine, like caching, data persistence, and inter-node replication.

Couchbase Server Interview Questions And Answers

Couchbase Interview Questions # 16) How Can Couchbase be integrated with Big Data and SQL?

A) Couchbase Data Platform includes built-in Big Data and SQL integration, allowing you to leverage tools, processing capacity, and data wherever it may reside.

Couchbase Interview Questions # 17) How Container and Cloud Deployments in Couchbase?

A) Couchbase supports all cloud platforms, as well as a variety of container and virtualization technologies to enable operational excellence.

Couchbase Interview Questions # 18) What are the different Couchbase Server Editions?

A) Couchbase Server is available in several editions: enterprise, community, and open source.

Couchbase Interview Questions # 19) What is cbq tool?

A) N1QL queries can be run from the command line, using the cbq tool.

Couchbase Interview Questions # 20) What are the different parts in the basic N1QL query?

A) A basic N1QL query has the following parts:

SELECT — The fields of each document to return.
FROM — The data bucket in which to look.
WHERE — The conditions that the document must satisfy.

Advanced Couchbase Interview Questions

Couchbase Interview Questions # 21) What is Query Workbench?

A) The Couchbase Web Console provides a Query Workbench, at which you can compose and execute N1QL queries.

Couchbase Interview Questions # 22) Can you explain about Role-Based Access Control Authentication?

A) Role-Based Access Control. This ensures that cluster-resources can only be accessed by users with appropriate privileges. Privileges are grouped in Couchbase-defined sets; and each set is associated with a specific role. Users can each be assigned one or more roles, and are thereby granted the privileges associated with each role.

23) What is Document?

A) A document refers to an entry in the database (other databases may refer to the same concept as a row). A document has an ID (primary key in other databases), which is unique to the document and by which it can be located.

The document value contains the actual application data; for example, a product document may contain information about the price and description. Documents are usually ( but not always) stored as JSON on the server. Because JSON is a structured format, it can be subsequently searched and queried.

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

24) What are Data structures in Couchbase?

A) Data structures in Couchbase are similar in concept to data structures in JavaScript:

Map is like a JavaScript Object, and is a key-value structure, where a value is accessed by using a key string.

List is like a JavaScript array and is a sequential data structure. Values can be placed in the beginning or end of a list, and can be accessed using numeric indexes.

Set is a wrapper over a list which provides the ability to handle unique values.

25) What is Cross Datacenter Replication (XDCR)?

A) Cross Datacenter Replication (XDCR) provides an easy way to replicate data from one cluster to another.

XDCR involves replicating active data to N+1 Couchbase Server clusters or external applications (e.g. Elastic, Spark, Storm, etc.). The clusters are regularly used for multiple, geographically diverse datacenters either for disaster recovery or to bring data closer to users for faster data access. For Couchbase clusters, this replication can be set up to be bi-directional or multi-directional.  Source – Couchbase Documentation

26) Is Couchbase an open source 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.

27) What is couchbase used for?


Couchbase Server is an open source, distributed, NoSQL document-oriented engagement database. It exposes a fast key-value store with managed cache for sub-millisecond data operations, purpose-built indexers for fast queries and a powerful query engine for executing SQL-like queries.

28) Who owns couchbase?


Couchbase, Inc. was created through the merger of Membase and CouchOne in February 2011. The merged company aimed to build an easily scalable, high-performance document-oriented database system, marketed with the term NoSQL. In August, 2011, a $14 million funding was led by Ignition Partners.

29) Distinguish between CouchDB and Couchbase server.


CouchDB: Apache CouchDB is capable of storing the JSON documents and also provides the facility to attach the non-JSON files to those documents.

Couchbase server: Couchbase server is capable of storing the credentials and key-values, thus, it will be able to store binary data or any other kind of data and also JSON documents. The couchbase server takes the help of a Memcached binary protocol for key-value functionalities and REST API’s SQL and view queries.

30) How can you say that a Couchbase Server is different from that of database software?


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

31) What is data manager in the Couchbase Server?


It is actually a functional block with some useful applications. Actually, it is responsible for the purpose of extracting, as well as storing the data from the applications. There are certain other important tasks which it perform and without making an impact of the overall functionality of the software.

32) What Is Vbucket?

Answer :

Vbucket is one of the ways of logically partitioning data because of this nature, it can distribute all over the nodes in a cluster. Each couchbase kind bucket that gets created in the cluster is automatically split up into a static set of slices, later they map to individual servers. They are used to allocate the information effectively along with throughout a cluster.

33) What Are The Tcp Ports Used To Listen To The Requests?

Answer :

The port numbers are configurable. The default ports are as below:

Port 11210 : It is a port which is openly accessible to clients implementing version 2.0 of the memcapable API. Those are “vBucket aware” clients and are depending on the hashing algorithm to map keys to one of a suitable number of “vBuckets”. The vBuckets later will get mapped to a server, providing a layer of indirection enabling vibrant cluster rebalancing, non-disruptive cluster expansion or contraction, replication and failover.

Port 11211 : The usual Memcached port number processes requests from, clients guiding version 1.0 of the memcapable API requirement. Those clients will be depending on a consistent hashing algorithm to map keys openly to servers in a variable-length server catalog.


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