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OCR H446 1.3.4 Search-engine indexing

Part 4 of 8 · H446 1.3.4 · Web technologies

Search results come from a provider's own index, not from a live sweep of the web at the moment someone submits a query. This worksheet holds crawling, indexing and query matching apart for H446 1.3.4, using a page that is discovered, changed and then removed to show why results can lag behind the live web.

Students will:

  • describe how a crawler discovers pages by following links from pages it already knows
  • explain what a provider records in its index and what a query actually searches
  • account for the delay between a live page changing and search results changing
  • evaluate common claims about publishing, crawling and how results are retrieved

Inside: 5 explanation cells, 1 multiple-choice question, 2 fill-in-the-blanks cells and 2 written answers. 25 marks, about 35 to 45 minutes.

Series: H446 1.3.4 · Web technologies, part 4 of 8.

Shared by Coding PathwayVerified teacher

  • 10 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 31 Aug 2026
  • Updated 3 Sept 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

Search-engine indexing

A search provider cannot usefully crawl every live page after each user submits a query. It discovers and revisits pages in advance, records selected information and searches its own index at query time.

Four separate states

Discovery, indexing and query-time retrieval are separate states 1 discover pagescrawler follows known links 2 collect and updateterms · positions · links · page address 3 provider-held indexstored records can be added, changed or removed 4 later user querysearch the provider's index and order resultsThe query does not crawl every live page at that moment.

A crawler or spider can begin from known pages and follow links. It collects information such as words, positions, links and addresses. The provider creates or updates index records. Later, a query is matched against that stored index and results can be ordered.

Worked state journey: local repair guides

Day 1: the provider knows page A. A links to new page B, so a crawler can discover B and record its address, terms and links. Day 4: B changes its heading. The live page changes immediately, but the provider's index may still contain the earlier record until B is revisited. Day 7: a user query searches the provider's current index, not every live page at that instant.

This explains both discoverability and delay. A valid page can exist without yet appearing in an index.

Multiple choice1 mark

What does a search provider normally search when a user submits a query?

  • AEvery live web page crawled from the beginning at that moment
  • BOnly the user's browser history
  • CThe website's own private database
  • DIts stored index of discovered page information
Fill in the blanks4 marks
A crawler can gap 1 links to discover pages, gap 2 page information, store or update an gap 3, and later match a user gap 4 against it.
  • follow
  • collect
  • index
  • query
  • PageRank
Written answer8 marks

A provider knows page M. M links to N; N later changes the phrase bike repair to cycle repair; then N is removed. Explain how discovery, recrawling and index updates could affect results at each stage. State why changes need not appear immediately.

Use discover/add, revisit/update and revisit/remove states. Do not claim an exact timetable.

Students type their answer here.

Apply the model independently

The remaining tasks change the context or reduce the support. Complete them without copying the worked model, then check that each explanation connects a mechanism to its consequence.

Written answer8 marks

Evaluate four claims: (1) Publishing guarantees immediate listing; (2) The crawler is the index; (3) A search query downloads every matching page before showing results; (4) Following links can help a crawler discover an unindexed page. Correct each inaccurate claim and justify the accurate one.

Keep discovery software, stored records and query-time use distinct.

Students type their answer here.

Fill in the blanks4 marks
A crawler or checkpoint gap 1 discovers pages. The provider stores selected information in an checkpoint gap 2. A user query searches that stored resource rather than the checkpoint gap 3 web. Page changes may appear after a later checkpoint gap 4.

Review your understanding

Before submitting, check that you can explain the main distinction in your own words, apply it in an unfamiliar context and justify each consequence rather than only naming a feature.