Couchbase Interview Questions and Answers

Full-text Search in Couchbase will allow you to query, create, and manage specially purposed indexes defined on the JSON document present within a Couchbase bucket. It provides Google-like search capabilities on JSON documents. Extensive capabilities are provided by Full-text Search (FTS) for natural language querying. Full-text search is powered by open-source indexing and search library called Bleve. The Bleve is written and developed in the Go programming language. The full-text search uses Bleve mainly to perform indexing of documents. Lyzers and pre-built text are included in Full-text Search for various languages such as English, Hindi, Italian, Arabic, Persian, etc. 

Couchbase is actually known as Membase. It is designed for the JSON document, distributed, and open-source database designed for business-critical applications. It also runs on-devices and manages synchronization to the server. The Core Architecture of Couchbase is designed and structured to simplify the process of building modern applications with a suitable data model to provide advanced security features, high availability, high performance, and high scalability. In order to gain an in-depth understanding of Couchbase architecture, you need to first understand the behavior of core run time capabilities and core components of the system.

The Couchbase Server consists of a single package installed on every node. The runtime systems included within the Couchbase Server are security architecture, replication architecture, storage architecture, caching layer architecture, and replication architecture. Couchbase components are specifically used to run independent workloads within the cluster. Core data services in Couchbase are used to perform CURD operations on all items present within buckets. Indexes are used to store multiple keyspaces in a single bucket. They also provide faster access to data present within buckets. In Couchbase, using SQL-like syntax you can query data with N1QL. 

Basically, Cluster Manager in Couchbase runs on all the nodes of a cluster. The Cluster Manager coordinates cluster-wide operations and maintains essential pre-node processes. The architecture of the cluster manager mainly consists of two processes such as babysitter and ns-server. The babysitter is responsible for maintaining a wide variety of Couchbase Server Processes. Ns-server is mainly used to manage the node’s participation in the cluster. 

Basically, the Couchbase Server contains one or more nodes, and each of which is a system running a single Couchbase Server instance. The node is a virtual or physical machine and its main aim is to host a single instance of Couchbase Server. The Couchbase Server is established on a node in four stages such as 1. Installed 2. Started 3. Initialized 4. Provisioned. The node can be a cluster of one server only when a variant of the fourth stage is achieved. You can add a node to the cluster after installation or during the installation. 

N1QL is a query language and it is basically pronounced as nickel. It is popularly considered as Couchbase next-generation query language. The N1QL query language gives application developers a very powerful and expressive SQL dialect with standard ANSI for manipulating, transforming, and querying data present in the JSON document. It is formally a declarative query language that extends SQL for JSON. You can query your data via a native framework. The query service allows you to extract data sources from the Couchbase server by issuing queries. The queries can be issued by using the query service tools, REST API, or a Couchbase SDK.

The key functional blocks present in Couchbase are 

• Data Manager
• Cluster Manager

Data Manager is a functional block that is mainly responsible for storing and extracting data useful for building applications.

The Cluster Manager coordinates cluster-wide operations and maintains essential pre-node processes. The architecture of the cluster manager mainly consists of two processes such as babysitter and ns-server.

Data Manager is a functional block that is mainly responsible for storing and extracting data useful for building applications. The data manager is a block of useful applications. Data Manager performs certain important and specific tasks without impacting the functionality of the software.

Storage Engine in Couchbase mainly stores data on disk by using Couchbase buckets. The storage engine mainly enables the Couchbase Server to hold a larger amount of data more efficiently than the size of memory. 

The Data Service in the Couchbase server provides access to data. It also provides access to data on disk and in memory. The memory allocated for data service is configurable. The architecture of Data Service is shown below.

The principal components of Data Service Architecture are KV Engine, Dispatcher, Scheduler, Checkpoint Manager, etc. 

The key features of Couchbase Server are as follows:

• Fastness: Couchbase Server is very fast and it facilitates the highest throughput and low latency.

• Reliable: It is enterprise-ready software and helps developers to build enterprise applications. 

• Simple: This server is very simple in terms of expanding and managing servers.