Couchbase Interview Questions & Answers

Couchbase Interview Questions

Are you a person inspiring to work with toughest technology? Are you a person with B.E or B. Tech in computers or Bachelor’s degree in the computers with experience then logon to Couchbase server originally known as Membase is an open source distributed multi model NoSQL document oriented db software package that is optimized for interactive applications. It has a flexible data model, is easily scalable provides consistent high performance and is always on that is 24hours and 7 days. With Couchbase server JSON documents are used to represent application objects and the relationships between objects. So track your future as Software Engineer in Testing, Performance Engineer, Solution Architect DBAExpert and so on by looking into Couchbase job interview question and answers given.

Couchbase Interview Questions And Answers

Couchbase Interview Questions
    1. Question 1. What Is Couchbase Server?

      Answer :

      Couchbase server is an easy, fast, elastic NoSQL database. It is also known as Membase, distributed, multi-model NoSQL file oriented database software package that is advanced for collective applications.

    2. Question 2. Is Couchbase An Open Sourse Software?

      Answer :

      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.

    3. Question 3. What Are The Basic Features Of The Couchbase Server?

      Answer :

      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.

    4. Question 4. Distinguish Between Couchdb And Couchbase Server?

      Answer :

      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.

    5. Question 5. How Many Functional Blocks Have Involved In Couchbase Server And Brief About Them?

      Answer :

      There are two different functional blocks of Couchbase server and are:

      • Data Manager
      • 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 “men capable” 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.

    6. Question 6. 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.

    7. Question 7. What Are The 4 Subsystems Which Function On Every Node?

      Answer :

      • Pulses : Watchdog develops regularly exchange a few words with the presently designated cluster head to offer wellbeing revises.
      • Progression Monitor : This is the subsystem to monitor on carrying out of the limited information executive, resuming unsuccessful procedures as needed and contributing condition data to the pulsing piece.
      • Pattern Manager : It is known that every node in the cluster has a pattern example: vBucket map, an intention map, etc. This subsystem will receive, monitor and process local configuration.
      • Worldwide Singleton Supervisor : This is of the subsystems and its task is to select cluster head if the previously voted head dies and monitoring “per-cluster” carries if the neighboring lump is the present chief.

    8. Question 8. What Vbucket Map Represents?

      Answer :

      The vBucket map is responsible for representing the state of a cluster once a currently running rebalance operation completes. The process called Rebalance Orchestrator correlate the target current maps to conclude which movement Tap Streams to create and administer. The operation of Rebalance will get exhaustive when the current and Target vBucket Maps are alike.

    9. Question 9. 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.

    10. Question 10. What Is The Importance Of Creating A Data Bucket?

      Answer :

      It makes important to create a Data Bucket since the couchbase server stores the data in Data Buckets. The “Default” bucket is created when the couchbase server is installed. The capacity of a data bucket to store the data is up to 20MB. If required, additional data buckets can be added. The bucket creation will have a limit when there is no sufficient space in RAM. Ex: limit the RAM/ Quota usage for the default bucket to 100 MB.

    11. Question 11. Couchbase Node Consists Of Which Elements?

      Answer :

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

    12. Question 12. What Is Cluster Manager In Couchbase?

      Answer :

      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.

    13. Question 13. Cluster Manager Uses Which Programming Language?

      Answer :

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

    14. Question 14. Replication And Fail-over?

      Answer :

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

    15. Question 15. What Is Data Manager In Couchbase?

      Answer :

      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.

    16. Question 16. What Is Data Format In Couchbase?

      Answer :

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

    17. Question 17. What Is Object-managed Cache In Couchbase Server?

      Answer :

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

    18. Question 18. What Is Storage Engine In Couchbase Server?

      Answer :

      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.

    19. Question 19. What Is N1ql?

      Answer :

      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.

    20. Question 20. Why Do We Use Couchbase Server?

      Answer :

      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

    21. Question 21. What Are The Benefits Of Using Couchbase?

      Answer :

      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.

    22. Question 22. What Is Full-text Search?

      Answer :

      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.

    23. Question 23. What Is Analytics In Couchbase?

      Answer :

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

    24. Question 24. Explain About The Core Database Engine In Couchbase?

      Answer :

      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.

    25. Question 25. How Can Couchbase Be Integrated With Big Data And Sql?

      Answer :

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

    26. Question 26. How Container And Cloud Deployments In Couchbase?

      Answer :

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

    27. Question 27. What Are The Different Couchbase Server Editions?

      Answer :

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

    28. Question 28. What Is Cbq Tool?

      Answer :

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

    29. Question 29. What Are The Different Parts In The Basic N1ql Query?

      Answer :

      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.

    30. Question 30. What Is Query Workbench?

      Answer :

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

    31. Question 31. Can You Explain About Role-based Access Control Authentication?

      Answer :

      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 hereby granted the privileges associated with each role.

    32. Question 32. What Is Document?

      Answer :

      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”]


    33. Question 33. What Are Data Structures In Couchbase?

      Answer :

      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.

    34. Question 34. What Is Cross Datacenter Replication (xdcr)?

      Answer :

      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.

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