Memcached MCQs (Multiple-Choice Questions)

Memcached is a general-purpose, free, open-source software, and distributed memory-caching system. Memcached is used for speeding up dynamic database-driven websites. It caches data and objects in RAM to reduce the number of times an external data source must be read.

Memcached MCQs: This section contains multiple-choice questions and answers on the various topics of Memcached. Practice these MCQs to test and enhance your skills on Memcached.

List of Memcached MCQs

1. Memcached is a ____.

  1. Centralized memory object caching system
  2. Distributed memory object caching system

Answer: B) Distributed memory object caching system

Explanation:

Memcached is a Distributed memory object caching system.

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2. Memcached is written in which of the following language?

  1. Python
  2. Ruby
  3. Java
  4. C

Answer: D) C

Explanation:

Memcached is written in C language.

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3. Is Memcached Open-source?

  1. Yes
  2. No

Answer: A) Yes

Explanation:

Memcached is open-source.

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4. What is the Memcached default port?

  1. 11220
  2. 11451
  3. 11211
  4. 11311

Answer: C) 11211

Explanation:

Memcached default port is 11211.

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5. What is the Memcached telnet command's basic syntax?

  1. $telnet HOST PORT
  2. $ HOST PORT
  3. $telnet HOST
  4. $telnet PORT_NAME

Answer: A) $telnet HOST PORT

Explanation:

The Memcached telnet command's basic syntax is: $telnet HOST PORT.

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6. The ____ command in Memcached is used to assign a new value to a new or existing key.

  1. Set
  2. Fix
  3. Change
  4. Setup

Answer: A) Set

Explanation:

The set command in Memcached is used to assign a new value to a new or existing key.

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7. The ____ command in Memcached is used to assign a value to a new key.

  1. Create
  2. Add
  3. Set
  4. Assign

Answer: B) Add

Explanation:

The add command in Memcached is used to assign a value to a new key.

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8. What will happen if you use add command to assign a value to a new key, and the key already exists?

  1. the output is NOT STORED.
  2. the output is STORED.
  3. the output is DUPLICATED

Answer: A) the output is NOT STORED.

Explanation:

The add command in Memcached is used to assign a value to a new key. If the key already exists, the output is NOT STORED.

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9. In the below syntax of add command, which of the following keyword in a syntax represent the data that needs to be stored?

add key flags exptime bytes [noreply]
  1. Key
  2. Flags
  3. Value
  4. Exptime
  5. Bytes

Answer: C) Value

Explanation:

Value represents the data that needs to be stored.

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10. The ____ command in Memcached is used to replace the value of an existing key.

  1. Swap
  2. Change
  3. Replace
  4. Substitute

Answer: C) Replace

Explanation:

The replace command in Memcached is used to replace the value of an existing key.

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11. If you are using replace command in Memcached and the key does not exist, what will happen?

  1. the output is NOT STORED.
  2. the output is STORED.
  3. the output is DUPLICATED

Answer: A) the output is NOT STORED.

Explanation:

The replace command in Memcached is used to replace the value of an existing key. If the key does not exist, the output is NOT STORED.

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12. The ____ command in Memcached is used to add data to an existing key.

  1. Extend
  2. Append
  3. Prepend
  4. Add

Answer: B) Append

Explanation:

The append command in Memcached is used to add data to an existing key.

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13. When using the append command the data is stored ____ the existing data.

  1. Before
  2. After
  3. Middle

Answer: B) After

Explanation:

The append command in Memcached is used to add data to an existing key. The data is stored after the key's existing data.

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14. The ____ command is used to append data to the beginning of an existing Memcached value for a specific key.

  1. Extend
  2. Append
  3. Prepend
  4. Add

Answer: C) Prepend

Explanation:

The prepend command is used to append data to the beginning of an existing Memcached value for a specific key.

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15. If the key does not exist while appending the data using prepend command then what will be the result?

  1. The prepend command will append at the end of the key if the key does not exist.
  2. The prepend command will fail if the key does not exist.
  3. The prepend command will append in the middle of any key if the key does not exist.

Answer: B) The prepend command will fail if the key does not exist.

Explanation:

The prepend command will fail if the key does not exist.

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16. What is CAS in Memcached?

  1. Check-And-Set
  2. Compare-And-Swap
  3. Both

Answer: C) Both

Explanation:

CAS stands for Check-And-Set or Compare-And-Swap.

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17. Which of the following command is used to set the data, if the data hasn't been updated since the last retrieve?

  1. Retrieve
  2. Set
  3. Recover
  4. CAS

Answer: D) CAS

Explanation:

If the data hasn't been updated since the last retrieve, the Memcached CAS command is used to set it.

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18. Which command is used to retrieve the value stored at the key?

  1. Retrieve
  2. Get
  3. Obtain

Answer: B) Get

Explanation:

The Memcached get command is used to retrieve the value stored at the key.

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19. Which command is used to remove an existing key from the Memcached server?

  1. Delete
  2. Drop
  3. Remove
  4. Erase

Answer: A) Delete

Explanation:

The Memcached delete command is used to remove an existing key from the Memcached server.

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20. Which of the following command in Memcached is used to increase the numeric value of an existing key?

  1. Increase
  2. Raise
  3. Increment
  4. Incr

Answer: D) Incr

Explanation:

Incr command in Memcached is used to increase the numeric value of an existing key.

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21. Which of the following command in Memcached is used to decrease the numeric value of an existing key?

  1. decrease
  2. lower
  3. Decrement
  4. Decr

Answer: D) Decr

Explanation:

Decr command in Memcached is used to decrease the numeric value of an existing key.

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22. As we know that the Decr command in Memcached is used to decrease the numeric value of an existing key, what will happen if the key is not numeric?

  1. NOT FOUND
  2. Returns Nothing
  3. CLIENT_ERROR cannot increment or decrement non-numeric value

Answer: C) CLIENT_ERROR cannot increment or decrement non-numeric value

Explanation:

CLIENT_ERROR cannot increment or decrement non-numeric value.

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23. In which year Memcached was launched?

  1. 2002
  2. 2004
  3. 2003
  4. 2007

Answer: C) 2003

Explanation:

Memcached's first version was released on May 22, 2003.

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24. Is Memcached a database?

  1. Yes
  2. No

Answer: B) No

Explanation:

Memcached is a memory cache, not a database. It just saves transient data.

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25. Which of the following command is used to close the connection?

  1. Close
  2. End
  3. Quit
  4. Delete

Answer: C) Quit

Explanation:

The quit command is used to close the connection.

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26. Which of the following command returns server statistics such as version, and connections?

  1. Statistics
  2. Stats
  3. Info
  4. Facts

Answer: B) Stats

Explanation:

The Memcached stats command returns server statistics such as PID, version, connections, and so on.

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27. Which of the following command returns item statistics such as count, age, and eviction?

  1. Statistics item
  2. Item
  3. Stats item

Answer: C) Stats item

Explanation:

The Memcached stats items command returns item statistics such as count, age, eviction, and so on, sorted by slab ID.

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28. Each Memcached have ____ unique key.

  1. One
  2. More than one
  3. Many

Answer: A) One

Explanation:

Each Memcached has one unique key.

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29. The ____ occurs when the cache expires and websites are attacked by many requests from the client at the same time.

  1. Dogpile effect
  2. Slab allocator
  3. LRU
  4. CAS

Answer: A) Dogpile effect

Explanation:

The Dogpile effect occurs when the cache expires and websites are attacked by many requests from the client at the same time.

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30. Dogpile effect can be prevented using which of the following?

  1. Scheduler Locker
  2. Semaphore Lock
  3. Deadlock
  4. Bootloader

Answer: B) Semaphore Lock

Explanation:

The dogpile effect can be prevented using a semaphore lock.

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31. Is Data stored in Memcached permanently stored?

  1. Yes
  2. No

Answer: B) No

Explanation:

No, data stored in Memcached is not permanently stored. It is temporally stored data.

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32. When the server is shut down or restarted, all Memcached data is ____?

  1. Restored
  2. Rolled Back
  3. Destroyed

Answer: C) Destroyed

Explanation:

When the server is shut down or restarted, all Memcached data is destroyed.

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33. What is LRU?

  1. Last recently used
  2. Late reset utilized
  3. Least recently utilized
  4. Least recently used

Answer: D) Least recently used

Explanation:

LRU stands for least recently used.

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34. Memcached use ____ to free up memory when it becomes full?

  1. TTL
  2. Slab allocator
  3. LRU

Answer: C) LRU

Explanation:

Memcached use LRU to free up memory when it becomes full.

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35. What is TTL?

  1. Total time left
  2. Time to live
  3. Total time live
  4. Time to load

Answer: B) Time to live

Explanation:

TTL stands for time to live.

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36. ____ refers to the length of time a value is held in Memcached before being evicted.

  1. TTL
  2. Slab allocator
  3. LRU

Answer: A) TTL

Explanation:

TTL refers to the length of time a value is held in Memcached before being evicted.

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37. The ____ command deletes all data (key-value pairs) from the Memcached server.

  1. Delete_all
  2. Drop_all
  3. Flush_all
  4. Remove_all

Answer: C) Flush_all

Explanation:

The flush_all Memcached command deletes all data (key-value pairs) from the Memcached server.

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38. The maximum number of concurrent connections is set to ____ by default.

  1. 8000
  2. 2000
  3. 1050
  4. 1024

Answer: D) 1024

Explanation:

The maximum number of concurrent connections is set to 1024 by default.

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39. Which of the following correctly states the meaning of eviction in Memcached?

  1. you've run out of Memory
  2. you're writing too quickly
  3. extstore can't keep up
  4. All of the above

Answer: D) All of the above

Explanation:

Evictions can indicate that you've run out of Memory or that you're writing too quickly and extstore can't keep up.

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40. In Memcached UDP server is ____ by default.

  1. Disabled
  2. Enabled

Answer: A) Disabled

Explanation:

In Memcached, the UDP server is Disabled by default.

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41. Is Memcached fault-tolerant?

  1. Yes
  2. No

Answer: B) No

Explanation:

Memcached is not a fault-tolerant tool.

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42. Does Memcached support the replication of data?

  1. Yes
  2. No

Answer: A) Yes

Explanation:

Yes, Memcached allows replication, which means that data may be replicated across numerous servers in a cluster.

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43. The maximum length of a key in Memcached is ____.

  1. 200 characters
  2. 250 characters
  3. 500 characters
  4. No limit

Answer: B) 250 characters

Explanation:

The maximum length of a key in Memcached is 250 characters.

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44. What is the maximum size of a value that can be stored in Memcached?

  1. 10 MB
  2. 2MB
  3. 1MB
  4. No limit

Answer: C) 1MB

Explanation:

The maximum size of a value that can be stored in Memcached is 1 megabyte (MB).

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45. What is the maximum TTL?

  1. 60 days
  2. 24 hours
  3. 90 days
  4. 30 days

Answer: D) 30 days

Explanation:

The maximum TTL is 30 days.

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46. ____ is the method of distributing a big data set over numerous Memcached servers in a cluster.

  1. Sharding
  2. Fragmentation
  3. Segmentation
  4. Dogpile effect

Answer: A) Sharding

Explanation:

Sharding is the method of distributing a big data set over numerous Memcached servers in a cluster.

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47. How many methods are there to update the Memcached when data changes?

  1. 5
  2. 4
  3. 3
  4. 2

Answer: D) 2

Explanation:

There are two methods to update Memcached when data changes:

  • By clearing the cache proactively:
  • By resetting the cache

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48. Which of the following command provides you with the version of Memcached?

  1. Ver
  2. Version—
  3. –version
  4. version

Answer: D) version

Explanation:

The version command provides you with the version of Memcached.

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49. Which of the following companies are using Memcached?

  1. Facebook
  2. Twitter
  3. WordPress
  4. Airbnb
  5. All of the above

Answer: E) All of the above

Explanation:

Following companies are using Memcached:

  • Facebook
  • Twitter
  • WordPress
  • Airbnb

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50. What are the alternatives to Memcached?

  1. Redis
  2. Couchbase
  3. Apache Ignite
  4. All of the above

Answer: D) All of the above

Explanation:

Following are the alternatives of Memcached:

  • Redis
  • Couchbase
  • Apache Ignite
  • Varnish

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