MCQs on Caching Techniques | PHP Advanced
Caching is an essential technique in optimizing web application performance by reducing server load and speeding up content delivery. This set of 30 MCQs covers various caching techniques, including PHP caching methods, query caching, HTTP headers, and CDNs to enhance web performance.
Caching Techniques – MCQs
1. Introduction to Caching
- What is caching in web development?
- a) Storing data for later use to reduce load time
- b) Compressing files to make them smaller
- c) Encrypting data for security
- d) Storing data temporarily in the database
- What does caching help to improve in web applications?
- a) Security
- b) Performance and speed
- c) Data accuracy
- d) Code quality
- Which of the following is a benefit of caching?
- a) Reduces the load on databases
- b) Increases server storage
- c) Reduces the need for backups
- d) Prevents hacking attempts
- Where is cached data typically stored?
- a) In the database
- b) In the client’s browser
- c) In the web server memory or disk
- d) In an external file system
- What does a cache miss refer to?
- a) Data found in the cache
- b) Data not found in the cache and needs to be fetched again
- c) Data deleted from the cache
- d) Data sent to the client directly from the server
- Which type of caching is used when content is stored for faster access on the client side?
- a) Server-side caching
- b) Client-side caching
- c) Database caching
- d) File-system caching
2. Caching with PHP (OPCache, Memcached, Redis)
- What is OPcache in PHP?
- a) A file system cache
- b) A PHP bytecode cache
- c) A database cache
- d) A session cache
- How does OPcache improve PHP performance?
- a) By storing compiled PHP bytecode in memory
- b) By caching SQL queries
- c) By compressing PHP files
- d) By storing HTML content in memory
- What type of cache is Memcached primarily used for?
- a) File caching
- b) Database query caching
- c) Object caching
- d) Page caching
- What is the main purpose of Redis in caching?
- a) Caching images
- b) Caching static files
- c) Storing and managing data with high availability
- d) Compressing data to reduce size
- Which of the following is a feature of Memcached?
- a) Persistent storage
- b) In-memory data storage for fast access
- c) Distributed disk-based storage
- d) Data encryption
- Which PHP extension is used to interact with Redis?
- a) Redis
- b) Memcached
- c) PDO
- d) OPcache
3. Query Caching
- What does query caching do in a database?
- a) Stores query results to avoid re-execution
- b) Compresses database queries
- c) Encrypts queries for security
- d) Prepares queries for faster execution
- How does query caching help improve performance?
- a) By storing the results of frequently executed queries
- b) By avoiding database connections
- c) By minimizing server-side processing
- d) By reducing the amount of disk space used
- In which case is query caching most beneficial?
- a) For non-repetitive queries
- b) For queries that change frequently
- c) For frequently repeated queries with the same result
- d) For large, complex queries
- Which of the following databases supports query caching?
- a) MySQL
- b) PostgreSQL
- c) MongoDB
- d) Oracle
- What is a potential drawback of query caching?
- a) It can slow down queries with frequently changing data
- b) It increases database storage space
- c) It encrypts cached data
- d) It requires additional hardware resources
- What happens when a query cache expires?
- a) The data is permanently deleted
- b) The query is re-executed to fetch fresh data
- c) The cache is updated automatically
- d) The cache is transferred to another server
4. HTTP Caching Headers
- What is the purpose of the
Cache-Controlheader in HTTP?- a) To prevent caching of resources
- b) To control the caching behavior of the browser and intermediate caches
- c) To ensure that data is not cached
- d) To specify the type of compression for resources
- Which HTTP header is used to specify the time a resource can be cached?
- a) Expires
- b) Cache-Control
- c) Pragma
- d) Last-Modified
- What does the
Expiresheader do in HTTP caching?- a) Specifies a specific date/time when the resource should be considered expired
- b) Specifies the cache duration in seconds
- c) Prevents caching of the resource
- d) Specifies the compression format of a resource
- What is the function of the
ETagheader in HTTP?- a) It identifies the resource to prevent caching
- b) It serves as a version identifier for the resource
- c) It prevents caching altogether
- d) It specifies the language of the resource
- How can you force the browser to always re-fetch a resource?
- a) By using a long expiration time
- b) By setting the
Cache-Control: no-storedirective - c) By using the
Expiresheader - d) By enabling query string versioning
- What does the
If-Modified-Sinceheader do in HTTP?- a) Forces the browser to reload a cached resource
- b) Indicates that the resource has been updated since the last request
- c) Checks if the resource is expired
- d) Provides a version number for the resource
5. Content Delivery Networks (CDNs)
- What is a Content Delivery Network (CDN)?
- a) A tool to compress content
- b) A distributed network of servers to deliver content efficiently to users
- c) A way to cache images locally
- d) A system for managing database connections
- How does a CDN improve website performance?
- a) By reducing the distance between the server and the user
- b) By compressing the website’s HTML files
- c) By storing data in the database
- d) By optimizing the code
- Which of the following is a major benefit of using a CDN?
- a) Faster content delivery and reduced latency
- b) Increased server load
- c) Enhanced database security
- d) Reduced file sizes
- Which type of content is commonly delivered by CDNs?
- a) Static files (images, CSS, JavaScript)
- b) Dynamic database queries
- c) Encrypted data
- d) HTTP headers
- How do CDNs reduce the load on origin servers?
- a) By delivering content directly to the user from distributed servers
- b) By caching database queries
- c) By optimizing HTML content
- d) By encrypting content
- What is one common feature of most CDNs?
- a) Automatic content caching at edge locations
- b) Real-time video streaming
- c) Secure data storage
- d) Content analysis and reporting
Answers
| QNo | Answer |
|---|---|
| 1 | a) Storing data for later use to reduce load time |
| 2 | b) Performance and speed |
| 3 | a) Reduces the load on databases |
| 4 | c) In the web server memory or disk |
| 5 | b) Data not found in the cache and needs to be fetched again |
| 6 | b) Client-side caching |
| 7 | b) A PHP bytecode cache |
| 8 | a) By storing compiled PHP bytecode in memory |
| 9 | c) Object caching |
| 10 | c) Storing and managing data with high availability |
| 11 | b) In-memory data storage for fast access |
| 12 | a) Redis |
| 13 | a) Stores query results to avoid re-execution |
| 14 | a) By storing the results of frequently executed queries |
| 15 | c) For frequently repeated queries with the same result |
| 16 | a) MySQL |
| 17 | a) It can slow down queries with frequently changing data |
| 18 | b) The query is re-executed to fetch fresh data |
| 19 | b) To control the caching behavior of the browser and intermediate caches |
| 20 | a) Expires |
| 21 | a) Specifies a specific date/time when the resource should be considered expired |
| 22 | b) It serves as a version identifier for the resource |
| 23 | b) By setting the Cache-Control: no-store directive |
| 24 | b) Indicates that the resource has been updated since the last request |
| 25 | b) A distributed network of servers to deliver content efficiently to users |
| 26 | a) By reducing the distance between the server and the user |
| 27 | a) Faster content delivery and reduced latency |
| 28 | a) Static files (images, CSS, JavaScript) |
| 29 | a) By delivering content directly to the user from distributed servers |
| 30 | a) Automatic content caching at edge locations |