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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Point out the correct statement.(a) MongoDB Enterprise provides support for Kerberos authentication of MongoDB clients to mongod and mongos(b) Kerberos is an industry standard authentication protocol for large client/server systems(c) Kerberos allows MongoDB and applications to take advantage of existing authentication infrastructure and processes(d) All of the mentioned |
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Answer» Correct answer is (d) All of the mentioned The explanation: In a Kerberos-based system, every participant in the authenticated communication is known as a “principal”, and every principal must have a unique name. |
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| 152. |
MongoDB supports tagging a range of _______ key values to associate that range with a shard or group of shards.(a) primary(b) secondary(c) shard(d) all of the mentioned |
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Answer» The correct answer is (c) shard The explanation: Those shards receive all inserts within the tagged range. |
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| 153. |
The TCP keepalive on the Azure load balancer is ______ seconds by default.(a) 100(b) 200(c) 240(d) None of the mentioned |
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Answer» Correct option is (a) 100 The explanation: You should set tcp_keepalive_time to 120 to ameliorate this problem. |
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| 154. |
On Linux the ______ manager can create a snapshot.(a) LVM(b) SVM(c) MMS(d) All of the mentioned |
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Answer» Correct answer is (a) LVM Easy explanation: You can create a backup by copying MongoDB’s underlying data files. |
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| 155. |
Point out the correct statement.(a) MMS offers point in time recovery of MongoDB replica sets(b) MongoDB provides a web interface that exposes diagnostic and monitoring information in a simple web page(c) db.Status() outputs an account of the state of a MongoDB instance(d) None of the mentioned |
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Answer» Right answer is (b) MongoDB provides a web interface that exposes diagnostic and monitoring information in a simple web page To explain I would say: The web interface is accessible at localhost: |
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| 156. |
Replica set configuration requires that the _______ have a value that is consistent among all members of the set.(a) replSetName(b) instance(c) MMS(d) all of the mentioned |
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Answer» The correct option is (a) replSetName Easy explanation: Use descriptive names for sets. Once configured, use the mongo shell to add hosts to the replica set. |
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| 157. |
___________ captures and returns the counts of database operations by type.(a) mongostat(b) mongod(c) mms(d) all of the mentioned |
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Answer» Correct option is (a) mongostat The explanation is: Use mongostat to understand the distribution of operation types and to inform capacity planning. |
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| 158. |
Which of the following provide acceptable performance levels for multiple mongod instances?(a) GridFS(b) SST(c) MMS(d) SSD |
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Answer» The correct choice is (d) SSD Easy explanation: Additionally, you may find that multiple databases with small working sets may function acceptably on a single system. |
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| 159. |
The net.http.RESTInterfaceEnabled setting for mongod enables a fully interactive administrative __________ interface, which is disabled by default.(a) Restful(b) Rest(c) WebService(d) All of the mentioned |
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Answer» Correct choice is (b) Rest The explanation: The REST interface does not support any authentication and you should always restrict access to this interface to only allow trusted clients to connect to this port. |
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| 160. |
___________ returns a general overview of the status of the database, detailing disk usage, memory use, connection, journaling, and index access.(a) dbStats(b) db.serverStatus()(c) db.stats()(d) none of the mentioned |
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Answer» The correct answer is (b) db.serverStatus() For explanation I would say: This command is rarely run directly. |
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| 161. |
When connected to a MongoDB instance, mongodump can adversely affect ______ performance.(a) mdump(b) mongodump(c) mongod(d) all of the mentioned |
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Answer» Right answer is (c) mongod Explanation: If your data is larger than system memory, the queries will push the working set out of memory. |
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| 162. |
_____ is a command-line tool for monitoring network use.(a) bwm-ng(b) bwm-g(c) bwm-n(d) bwm-ngs |
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Answer» Correct choice is (a) bwm-ng The explanation: If you suspect a network-based bottleneck, you may use bwm-ng to begin your diagnostic process. |
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| 163. |
For each _______ the Kerberos Key Distribution Center (KDC) maintains a database of the realm’s principal and the principal’s associated “secret keys”.(a) key(b) realm(c) document(d) none of the mentioned |
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Answer» The correct choice is (b) realm For explanation I would say: Principals belong to administrative units called realms. |
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| 164. |
_____ bit builds of mongod enable journaling by default.(a) 8(b) 16(c) 32(d) 64 |
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Answer» Right answer is (d) 64 Easiest explanation: Journaling ensures single instance write-durability. |
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| 165. |
________ do not typically provide sufficient performance to support a MongoDB deployment.(a) RAID-5(b) RAID-10(c) RAID-7(d) None of the mentioned |
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Answer» Correct choice is (a) RAID-5 Easy explanation: Most MongoDB deployments should use disks backed by RAID-10. |
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| 166. |
Point out the wrong statement.(a) As of version 2.0.0, there are no control scripts for mongos(b) The mongodb-enterprise package includes various control scripts, including the init script /etc/rc.d/init.d/mongod(c) You must configure SELinux to allow MongoDB to start on Red Hat Linux-based systems(d) None of the mentioned |
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Answer» Right option is (a) As of version 2.0.0, there are no control scripts for mongos To explain: As of version 3.0.0, there are no control scripts for mongos.The mongos process is used only in sharding. |
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| 167. |
Which of the following is the Ubuntu package management tool?(a) wapt(b) dpkg(c) capt(d) wat |
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Answer» Right option is (b) dpkg The best I can explain: The Ubuntu package management tools (i.e. dpkg and apt) ensure package consistency and authenticity by requiring that distributors sign packages with GPG keys. |
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| 168. |
The _________ message limit can result in the truncation of the audit messages.(a) oplog(b) syslog(c) evallog(d) none of the mentioned |
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Answer» Correct option is (b) syslog For explanation: The auditing system will neither detect the truncation nor error upon its occurrence. |
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| 169. |
Point out the correct statement.(a) Config servers are not replica sets(b) Sharding requires a number of mongod instances with different configurations(c) The config servers store the cluster’s metadata, while the cluster distributes data among one or more shard servers(d) None of the mentioned |
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Answer» The correct answer is (d) None of the mentioned The best explanation: The command line and configuration file interfaces provide MongoDB administrators with a large number of options and settings for controlling the operation of the database system. |
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| 170. |
___________ is used to determine whether a query is a covered query.(a) explainstats()(b) explain()(c) explainall()(d) all of the mentioned |
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Answer» Right answer is (b) explain() The best explanation: db.collection.explain() provides information on the execution of other operations, such as db.collection.update(). |
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| 171. |
MongoDB only provides Enterprise packages for Ubuntu ________ LTS.(a) 13.04(b) 12.10(c) 12.04(d) 13.10 |
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Answer» Right answer is (c) 12.04 For explanation: The package structure and names have changed as of version 2.6. |
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| 172. |
Which of the following is a utility to check disk I/O performance independently of MongoDB?(a) mongoperf(b) mongoio(c) mongod(d) none of the mentioned |
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Answer» The correct answer is (a) mongoperf For explanation: Specify options to mongoperf using a JavaScript document. |
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| 173. |
The audit file rotates at the same time as the ________ log file.(a) Client(b) Server(c) Application(d) All of the mentioned |
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Answer» The correct option is (b) Server The best I can explain: Printing audit events to a file in JSON format degrades server performance more than printing to a file in BSON format. |
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| 174. |
_____________ is used to control mongod commits in the journal.(a) commitIntervMs(b) commitInterval(c) commitIntervalMs(d) all of the mentioned |
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Answer» Right answer is (c) commitIntervalMs Best explanation: For replica sets, write operations are durable only after a write replicates and commits to the journal on a majority of the voting members of the set. |
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| 175. |
The ___ field contains the sequence number of the chunk.(a) x(b) array(c) field(d) n |
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Answer» Correct option is (d) n Explanation: GridFS numbers all chunks, starting with 0. |
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| 176. |
Point out the correct statement.(a) ObjectIds are small, likely unique, fast to generate, and ordered(b) ObjectIds are large, likely unique, and ordered(c) ObjectIds values consists of 18-byte(d) All of the mentioned |
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Answer» The correct choice is (a) ObjectIds are small, likely unique, fast to generate, and ordered Explanation: In MongoDB, documents stored in a collection require a unique _id field that acts as a primary key. |
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| 177. |
_______ is /srv/mongodb, which specifies where MongoDB will store its data files.(a) dbPath(b) dbPathSts(c) db.Op(d) none of the mentioned |
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Answer» Correct option is (a) dbPath To explain: The user account that mongod runs under will need read and write access to this directory. |
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| 178. |
Point out the wrong statement.(a) Query selectivity refers to how well the query predicate excludes or filters out documents in a collection(b) Query selectivity can determine whether or not queries can use indexes effectively or even use indexes at all(c) More selective queries match a larger percentage of documents(d) All of the mentioned |
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Answer» The correct option is (c) More selective queries match a larger percentage of documents Explanation: More selective queries match a smaller percentage of documents. |
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| 179. |
To view the contents of the file, pass the file to the MongoDB utility ___________(a) bsonlog(b) bsonout(c) bsondump(d) SelectIndexes |
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Answer» Correct choice is (c) bsondump Best explanation: The following converts the audit log into a human-readable form and output to the terminal: bsondump data/db/auditLog.bson . |
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| 180. |
Clients can set a __________ value as part of a replica acknowledged write concern.(a) timeout(b) wtimeout(c) waittimeout(d) none of the mentioned |
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Answer» Correct choice is (b) wtimeout Easiest explanation: If the write concern is not satisfied in the specified interval, the operation returns an error, even if the write concern will eventually succeed. |
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| 181. |
_________ is a binary serialization format used to store documents and make remote procedure calls in MongoDB.(a) BSON(b) GridFS(c) JSON(d) None of the mentioned |
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Answer» Correct answer is (a) BSON For explanation: BSON supports many data types as values in documents. |
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| 182. |
MongoDB documents are composed of field-and-value pairs and have the following structure?(a) field1:; value1(b) field1: value1;(c) field1: value1(d) none of the mentioned |
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Answer» The correct answer is (c) field1: value1 The explanation: The value of a field can be any of the BSON data types, including other documents, arrays, and arrays of documents. |
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| 183. |
Indexes are typically available in ______ or located sequentially on disk.(a) RAM(b) ROM(c) CMOS(d) None of the mentioned |
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Answer» The correct answer is (a) RAM Explanation: Querying only the index can be much faster than querying documents outside of the index. |
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| 184. |
MongoDB does not ___________ modifications made before the wtimeout interval expired.(a) commit(b) rollback(c) save(d) all of the mentioned |
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Answer» Correct answer is (b) rollback The best I can explain: The driver’s ability to detect network errors depends on the system’s networking configuration. |
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| 185. |
Point out the wrong statement.(a) Some documents created by internal MongoDB processes may have duplicate fields(b) no MongoDB process will ever add duplicate fields to an existing user document(c) The maximum BSON document size is 16 megabytes(d) None of the mentioned |
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Answer» Right choice is (c) The maximum BSON document size is 16 megabytes To explain I would say: The maximum document size helps ensure that a single document cannot use excessive amount of RAM or, during transmission, excessive amount of bandwidth. |
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| 186. |
With an __________ write concern, MongoDB does not acknowledge the receipt of write operations.(a) Nacknowledged(b) Acknowledgement(c) Acknowledged(d) Unacknowledged |
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Answer» Correct choice is (d) Unacknowledged Explanation: Unacknowledged is similar to errors ignored. |
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| 187. |
To store documents larger than the maximum size, MongoDB provides the _______ API.(a) Grid(b) MMS(c) GridFS(d) None of the mentioned |
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Answer» Right choice is (c) GridFS To explain I would say: MongoDB preserves the order of the document fields following write operations. |
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| 188. |
Point out the correct statement.(a) Read operations on sharded clusters are most efficient when directed to a specific shard(b) Sharded clusters allow you to partition a data set among a cluster of mongod instances in a way that is nearly transparent to the application(c) For a sharded cluster, applications issue operations to one of the mongos instances associated with the cluster(d) All of the mentioned |
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Answer» The correct choice is (d) All of the mentioned The best I can explain: Queries to sharded collections should include the collection’s shard key. |
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| 189. |
___________ concern describes the guarantee that MongoDB provides when reporting on the success of a write operation.(a) Write(b) Read(c) Update(d) None of the mentioned |
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Answer» The correct option is (a) Write For explanation I would say: The strength of the write concerns determine the level of guarantee. |
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| 190. |
_______ concern describes the guarantee that MongoDB provides when reporting on the success of a write operation.(a) Write(b) Read(c) Read only(d) SSD |
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Answer» The correct choice is (a) Write For explanation: The strength of the write concerns determine the level of guarantee. |
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| 191. |
You cannot use _________ to change the value of expireAfterSeconds of an existing index.(a) createIndex()(b) dropIndex()(c) removeIndex()(d) none of the mentioned |
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Answer» The correct option is (a) createIndex() For explanation: Instead use the collMod database command in conjunction with the index collection flag. Otherwise, to change the value of the option of an existing index, you must drop the index first and recreate. |
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| 192. |
Point out the correct statement.(a) TTL indexes expire documents after the specified number of seconds has passed since the indexed field value(b) TTL indexes are special compound indexes(c) If a document does not contain the indexed field, the document will expire(d) None of the mentioned |
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Answer» Correct answer is (a) TTL indexes expire documents after the specified number of seconds has passed since the indexed field value For explanation I would say: The expiration threshold is the indexed field value plus the specified number of seconds. |
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| 193. |
Secondary members replicate _________ operations from the primary.(a) Update(b) Drop(c) Insert(d) None of the mentioned |
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Answer» The correct answer is (d) None of the mentioned Explanation: On replica sets, the TTL background thread only deletes documents on the primary. |
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| 194. |
You cannot create a TTL index on a ________ collection.(a) Sharded(b) Capped(c) Primary(d) None of the mentioned |
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Answer» Correct answer is (b) Capped Best explanation: MongoDB cannot remove documents from a capped collection. |
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| 195. |
A collection with a TTL index has __________ enabled.(a) usePowerOf3Sizes(b) usePowerOf2Sizes(c) usePowerOf4Sizes(d) none of the mentioned |
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Answer» Correct option is (b) usePowerOf2Sizes To explain I would say: As a result of enabling usePowerOf2Sizes, MongoDB must allocate more disk space relative to data size. |
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| 196. |
Which field does not support TTL indexes?(a) _identity(b) _option(c) _id(d) None of the mentioned |
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Answer» The correct option is (c) _id For explanation I would say: You cannot create a TTL index on a capped collection because MongoDB cannot remove documents from a capped collection. |
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| 197. |
Which of the following is a wide-column store?(a) Cassandra(b) Riak(c) MongoDB(d) Redis |
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Answer» The correct option is (a) Cassandra Explanation: Wide-column stores such as Cassandra and HBase are optimized for queries over large datasets, and store columns of data together, instead of rows. |
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| 198. |
Which of the following is a NoSQL Database Type?(a) SQL(b) Document databases(c) JSON(d) All of the mentioned |
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Answer» The correct option is (b) Document databases For explanation: Document databases pair each key with a complex data structure known as a document. |
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| 199. |
Which of the following collection do not support the TTL property?(a) Compound indexes(b) Primary indexes(c) Composite indexes(d) All of the mentioned |
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Answer» Correct choice is (a) Compound indexes Explanation: The TTL index is a single field index. |
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| 200. |
The ___________ provides information for various lock types and lock modes held during the operation.(a) admin.system.authlocks(b) system.profile.locks(c) admin.system.locks(d) all of the mentioned |
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Answer» Right answer is (b) system.profile.locks Explanation: MongoDB uses reader-writer locks that allow concurrent readers shared access to a resource, such as a database or collection, but give exclusive access to a single write operation. |
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