Top Answers to Couchbase Interview Questions
1. Compare Couchbase and MongoDB
|Scalability||Seamless scalability||Multi-step scalability|
|Uptime||Always up||Needs maintenance|
2. Is Couchbase an open sourse software?
Truly. Couchbase can be perceived as an open source software delivered under the Apache 2.0 permit with an endeavor and network version. Couchbase is an appropriated diverse NoSQL record arranged database software bundle that is progressed for aggregate applications and open-source software.
3. What is Couchbase Server?
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.
4. What are the basic features of the Couchbase server?
The fundamental highlights of the Couchbase Server are
Quick – Couchbase is known for its briskness. Couchbase server encourages the lower inertness and most elevated throughput. The exhibition cost will be low and it is a striking sign .
Basic – Couchbase server is basic regarding overseeing, introducing, getting, extending and utilizing it. In a Couchbase server, it isn’t important to make and oversee patterns, as an archive database without normalizing and tuning of the database.
Flexible – The Couchbase server will convey the data and I/O over virtual machines or ware servers, in this way it can make it simple to relate the ideal amount of assets to the changing needs of an application. In couchbase server the hubs can be improved from 1 to 100 tons in a bunch and furthermore can get diminished to continue application execution.
Dependable – Couchbase server is stable and endeavor prepared software, so anybody can depend on strategic applications.
5. Distinguish between CouchDB and Couchbase server.
CouchDB: Apache CouchDB is fit for putting away the JSON records and furthermore gives the office to connect the non-JSON documents to those documents.Couchbase server: Couchbase server is fit for putting away the certifications and key-values, subsequently, it will have the option to store double data or some other sort of data and furthermore JSON archives. The couchbase server takes the assistance of a Memcached paired convention for key-esteem functionalities and REST API’s SQL and view inquiries.
6. How many functional blocks have involved in Couchbase server and brief about them?
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 “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.
7. What is vBucket?
Vbucket is one of the methods of legitimately dividing data as a result of this nature, it can appropriate everywhere on the hubs in a group. Each couchbase kind basin that gets created in the group is consequently separated into a static arrangement of cuts, later they guide to singular servers. They are utilized to designate the data adequately alongside all through a bunch.
8. What are the 4 subsystems which function on every node?
- 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.
9. What vBucket Map represents?
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.
10. What are the TCP ports used to listen to the requests?
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.
11. What is the importance of creating a Data Bucket?
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.