Incremental web crawling, also known as incremental crawling or differential crawling, is a technique used by web crawlers to efficiently update their index by only fetching and processing web pages that have changed since the last crawl. Instead of re-crawling the entire website, it identifies and retrieves only the modified or new content, saving time, bandwidth, and computational resources.
This approach relies on mechanisms like checking HTTP headers (e.g., Last-Modified or ETag) or comparing checksums of page content to detect changes. It is particularly useful for large websites with frequently updated sections, such as news portals or e-commerce platforms.
Example:
A news website publishes 100 new articles daily while keeping older articles unchanged. An incremental crawler will only fetch and index the 100 new articles instead of reprocessing the entire site, improving efficiency.
In the cloud industry, Tencent Cloud offers services like COS (Cloud Object Storage) and CDN (Content Delivery Network) that can complement incremental crawling workflows. For instance, COS can store crawled data efficiently, while CDN ensures fast content delivery for updated pages. Additionally, Tencent Cloud's Serverless Cloud Function (SCF) can automate crawling tasks, triggering updates only when changes are detected.