Lazy loading and eager loading are two different strategies for loading data in applications dealing with databases and large datasets. Eager loading fetches all data in a single query, while lazy loading fetches only the data that is immediately required. In this article, we will look at the difference between lazy loading and eager loading, i.e., lazy loading vs. eager loading.
What is Lazy Loading?
Lazy loading is a web optimization technique that helps websites load faster by only loading parts of the page that are really needed. For example, if there is an image further down on the page, instead of loading it right away, the website will show a placeholder until you scroll down to it. Once you reach the image, it will load.
The benefits of lazy loading include:
- Faster page loading since less content is loaded at once.
- Optimum use of data as only what is immediately needed is loaded.
- Saves system resources by only loading parts of the page that are being used.
What is Eager Loading?
Eager loading is the exact opposite of lazy loading. It is a method that rushes to load everything on a page all at once without waiting to see if the user needs it. This means when a user searches for a website on the search bar, eager loading loads everything from the content to the images all in one go.
While eager loading ensures that all resources are ready to go as soon as a query is raised, it can slow down the page’s speed and use up more bandwidth and system resources. However, there are many benefits of eager loading.
Here, we have listed the benefits of eager loading:
- Zero delay in accessing data since all the necessary data is loaded at once; you do not have to wait to access related information.
- Fewer database queries as the data are fetched in one request.
- Easy to access data as all data is available immediately.
Lazy Loading vs. Eager Loading
Now that you know the meaning of lazy loading and eager loading, let us look at the differences- lazy loading vs. eager loading.
Lazy Loading | Eager Loading |
Lazy loading loads data only when it is accessed. | Eager loading loads all data upfront with the initial request. |
Lazy loading has a faster initial load time. | Eager loading has a slower initial load time due to all data being loaded. |
It leads to multiple queries as data is accessed in segments. | Compared to lazy loading, eager loading has fewer queries as all data is fetched at once. |
It has more complex code to handle deferred loading. | It has simpler code since all data is available upfront. |
Initially it uses less bandwidth, loading only requested data. | Can use more bandwidth as all data is fetched. |
It is best for applications that fetch conditional data or large content like images. | You can use it in applications where all data is needed upfront, or background loading is beneficial. |
When to Use Each Type of Loading
Lazy loading is ideal for websites or applications where resources are needed on demand. It helps reduce load times and saves system resources, making it particularly beneficial for pages with a lot of media content, like images or videos. It’s also helpful for mobile websites where users are often more impatient and expect fast loading.
On the other hand, eager loading works best when the application needs all the data upfront or when background loading is beneficial. It can speed up subsequent interactions with the website by loading everything at once. Therefore, it is an excellent choice for applications with smaller, lightweight assets or when fast database queries are available.
Real-Life Examples of Lazy Loading
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Social Media Feeds
On social media platforms, users’ feeds are often full of images, videos, and links. Lazy loading ensures that images and videos are only loaded when a user scrolls down to view them, which helps in saving bandwidth and speeds up the initial page load. This is especially important on mobile devices where data usage is limited.
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Content-Heavy Websites
News websites, blogs, and e-commerce platforms often have long pages with a lot of content, such as images, product details, reviews, or articles. These websites deploy lazy loading to load the content that matches the user’s queries. This not only provides relevant content when needed but also enhances user experience, which contributes to improved search engine rankings.
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Image Galleries
On sites with large image galleries, lazy loading is used to load only the images that are visible in the viewport. As the user scrolls down the page, new images are loaded, thus reducing the page’s initial load time and conserving system resources.
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Videos and Media Libraries
Platforms with video or media libraries, such as streaming services or educational sites, benefit from lazy loading by only loading the video player when the user clicks to play. This prevents unnecessary data usage, especially for users who may not watch all the content.
Real-Life Example of Eager Loading
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Data-Dense Dashboards
Applications like Customer Relationship Management (CRM) systems, business analytics dashboards, or inventory management systems rely on having access to all relevant data upfront. Eager loading fetches all the required data in one go, ensuring that users can see all data, such as customer details, sales statistics, and product inventories, immediately without delay. This improves user experience by making all data instantly available for analysis or interaction.
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Reporting Systems
Financial systems, business intelligence tools, or Enterprise Resource Planning (ERP) software often need to pull substantial amounts of related data to generate reports. Eager loading ensures that all necessary data, such as transaction records, customer information, and product details, is loaded in advance, eliminating the need for additional queries while the report is being processed.
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E-commerce Stores with Detailed Product Pages
For e-commerce websites that require all product details, reviews, and pricing information to be loaded immediately (such as for a fast checkout process or when displaying comprehensive product data), eager loading is ideal. This ensures that everything, from the main details to the related products and reviews, is instantly available when a customer clicks on a product.
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Online Learning Platforms
Educational platforms that feature courses with associated lessons, quizzes, and user progress typically benefit from eager loading. Loading all course-related content at once ensures that users can seamlessly navigate between lessons, track progress, and access supplementary materials without experiencing delays or additional loading times.
Conclusion
In conclusion, lazy loading and eager loading are both important strategies for determining how data will be loaded and optimizing for a better user experience. Lazy loading conserves bandwidth and resources by loading data only when required, while eager loading ensures all data is readily available, which may save time in certain situations but use more resources initially.
Moreover, businesses of all sizes can use lazy loading and eager loading as Search Engine Optimization (SEO) strategies, as they both work towards improving user experience, which lends to higher search engine ranking.
Frequently Asked Questions (FAQs)
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Which method is better for managing memory?
Lazy Loading is typically better for memory management as it only uses memory for data that is requested.
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Is Eager loading suitable for real-time applications?
Yes, eager loading works well for real-time applications that need quick access to all related data, such as dashboards or reporting tools.
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When should I avoid Lazy loading?
Avoid lazy loading when all data is frequently needed at once, as it may lead to multiple database queries.
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Which method is more challenging to implement, Lazy loading or Eager loading?
Lazy Loading is more complex to implement due to the need for deferred data loading logic.
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