SharePoint index and crawling timeframes

Question

Hi,

We have migrated to SharePoint from another document management system over the last weekend, and there are about 6 million items that were migrated.

1. How long does SharePoint usually take to crawl and index the sites?
2. Is there a schedule or frequency for the crawling and indexing of the sites?
3. Can we expect that the search results will improve as the crawling and indexing progresses?
4. Is it a good idea to re-crawl and re-index all the sites? (I understand that this will overload SharePoint).

Thank you,

Nishanth Chakkere

Answer 1

Hi @Nishanth Chakkere ,
Good days. Welcome to Q&A forum!

For your questions, please see the following:

1. How long does SharePoint usually take to crawl and index the sites?

• Continuous Crawling: SharePoint Online uses a continuous crawl model instead of scheduled full crawls. Once content is migrated (or updated), the crawler works in the background to pick up changes. For a very large migration (e.g., 6 million items), it can take from 24 hours up to several days for the entire set of items to be fully indexed. The actual duration depends on several factors such as the number of items, document sizes, metadata complexity, and overall system load.
• Gradual Indexing: You may notice that some items appear in search results almost immediately, but the index “catches up” over time. In large environments, it’s common for search results to improve incrementally as more items are processed.

2. Is there a schedule or frequency for the crawling and indexing of the sites?

• No Fixed Schedule (Continuous Process): Unlike on‑premises SharePoint (which may be configured with full crawls on a schedule), SharePoint Online continuously monitors and indexes content changes. There isn’t a fixed “crawl every X hours” schedule. Instead, changes—including new documents and modifications—are picked up almost continuously by the Microsoft Search service.
• Incremental Updates: The search index is updated incrementally. This means that when new content is added or existing content is changed, those changes are gradually reflected in the search index without manual intervention.

3. Can we expect that the search results will improve as the crawling and indexing progresses?

• Improved Relevance Over Time: Yes. Initially, after migration, search results may be incomplete or not as accurate because not all items have been indexed yet. As the continuous crawl processes the millions of items, search queries will gradually return more comprehensive and relevant results.
• Consistent Experience: Once the entire site collection is fully indexed, users should see search results that accurately reflect the migrated content—including support for metadata-based refiners and other query enhancements.

4. Is it a good idea to re-crawl and re-index all the sites?

• Avoid Forcing a Full Crawl: In SharePoint Online, you cannot manually trigger a full crawl in the same way as in on‑premises SharePoint. Although you can re-index individual lists or libraries by using the “Reindex Library” or “Reindex Site” options in settings, doing this for all sites or for millions of items is generally not recommended.
• Potential Impact: Manually triggering re-indexing on a large number of items may overload the service and cause performance issues. The recommended approach is to let the continuous crawl process run naturally.
• Best Practice: If you suspect certain libraries or sites have not been indexed properly (for example, if you see that search results are not improving after several days), you can manually trigger re-indexing for those specific libraries or sites via their settings. For example, go to Library Settings > Advanced Settings and click Reindex Library.

Hope this can help.

Please do let us know if you have any further queries.

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