Crawling & learning process

In the previous section, you successfully linked all your company apps to Glean. Now, three essential background processes will take place, each crucial for optimizing Glean's functionality:

1. Crawling - Glean fetches data from your connected apps.
2. Indexing - Glean creates a model of the data that was fetched and incorporates it into your organization's search index.
3. Learning - Glean processes the data that was fetched using Machine Learning (ML) to create a search and ranking algorithm tailored to your organization's data and users.

Timelines for completion

The time required to complete all three processes will vary depending on the size of your organization and the volume of content that Glean needs to process. The combined crawling and indexing processes can take approximately:

• Two to three days to complete for a typical small organization, or small volume of content.
• 10 to 14 days for a typical large organization, or large volume of content.

The machine learning (ML) process can take an additional two to 14 days, depending on:

1. The GCP or AWS region that your Glean tenant was deployed to (and the tier of TPU/GPU hardware available in that region).
2. The amount of content that needs to be processed as part of each ML workflow.

These times should be used as an estimate only.

Your Glean engineer will advise you once all crawling, indexing, and learning processes have been completed. The remainder of this document will cover these processes in more detail.

For now, you can proceed to the next step: Populate Content.

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About crawling and indexing

When you initiate a crawl for a data source for the first time, the crawling and indexing processes are initiated. During this time, Glean will:

1. Crawl the content (and associated permissions & activity metadata) for the selected data source.
2. Create the Glean Knowledge Graph by indexing the crawled content, mapping it together, and creating a real-time model that can be referred to in response to a user's query.

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Crawling is the process in which Glean fetches data from within your organization's sources of data for the purposes of creating the search index.

The Knowledge Graph is a real-time model of your organization's indexed information. It is a map that links all content, people, permissions, language, and activity within your organization. It is designed to provide users with the most personalized and relevant results for their queries in a matter of milliseconds.

Indexing is the process in which Glean makes content ready for display in search results by creating (or updating) your organization's Knowledge Graph: the mapping between all content, people, permissions, language, and activity in the company.

Check the crawling and indexing status

You can check the status of your in-progress crawls at any time by going to  Admin Console → Platform → Data sources and reviewing the table of configured apps.

When a data source is undergoing its initial sync, it will appear under the Initial sync in progress section, which is split into two phases:

1. Crawling (step one of two) - Glean is actively fetching content and metadata from the data source.
2. Indexing (step two of two) - Glean is processing the crawled content and incorporating it into the Knowledge Graph.

Once both crawling and indexing are complete for a data source, it will move from Initial sync in progress to the All data sources section, where it will appear alongside other fully-synced sources.

For each data source, you'll see:

• Items synced - The total number of items (documents, messages, files, etc.) that have been crawled and indexed. If a document has been crawled and indexed, it's visible in Glean.
• Change rate (items/day) - The number of changes (edits, additions, deletions) synced in the past 24 hours, reflecting ongoing freshness after initial sync completes.

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Status and metrics refresh on an hourly cadence. If you don't see immediate updates after making changes, check back in about an hour.

Check the status of your in-progress crawls at any time by going to Admin Console → Platform → Data sources

Crawling and Indexing FAQ

Crawling (Step one of two)

The initial crawl for any datasource will always take a while; the total time of which is dependent on two key factors:

The size of the datasource (For example, the number of documents/messages, and the size of each). The rate limit(s) of the datasource vendor's API.

If a datasource vendor's API has a low rate limit, this will affect how quickly Glean can crawl it for items. Likewise, datasources containing a large number of documents, files, or messages, will also take longer to crawl.

Some datasources share a rate limit across all integrated applications (like Glean). For these datasources, crawling time is typically slower, as Glean must be careful not to exhaust the entire rate limit threshold itself.

You can monitor crawling progress by checking the Initial sync in progress section under Crawling (step one of two) and watching the Items synced metric increase.

Indexing (Step two of two)

The indexing process works in parallel with the crawling process. That is, content that has been crawled is processed by Glean's indexer while other content is still being crawled.

While the crawling speed is heavily dependent on the volume of data AND the API rate limit, the indexing speed is conversely heavily dependent on compute resources. The health of each deployment's index and compute resources dedicated to the indexing process is carefully monitored by Glean's SRE team.

Once crawling begins to complete, you'll see the data source move to the Indexing (step two of two) phase in the Initial sync in progress section.

Total Time Required

For a typical enterprise datasource, expect the complete initial crawling and indexing processes to take anywhere from 3 days, up to 14 days for large datasources with moderate API rate limits. Once both phases complete, the data source will move to the All data sources section.

Yes. Each data source configured has its own unique crawler that dynamically scales based on demand. This ensures that multiple data sources can be crawled in parallel without impact to the time required to complete each crawl.

When a full (initial) crawl of a data source is initiated, it captures the state of all documents and content up to the exact timestamp when the crawl started. If any documents are modified or created after this timestamp, they will be processed and incorporated into the search index in one of two ways:

• Webhooks: Most datasources support webhooks, which Glean leverages to be notified of any content changes. When a webhook is received, it is processed within 1-5 minutes, depending on the datasource.
• Incremental Crawls: Glean performs an incremental crawl of each datasource every 24 hours. These crawls focus on identifying and incorporating changes that have occurred since the last crawl that were not captured via webhooks. This ensures that all recent modifications are captured.

Both webhooks and incremental crawls operate independently and run concurrently with any active full crawls. This design ensures that document updates are processed efficiently and that the system remains up-to-date with the latest changes.

The Access Verification page allows admins to resolve questions related to the visibility of specific documents within Glean. See Verify if a document is visible in Glean for more details.

If you are experiencing slow or stalled progress during crawling and indexing, refer to the Using metrics for troubleshooting section of the monitoring page to diagnose the issue.

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About machine learning

Once the crawling and indexing processes have been completed, Glean will initiate several Machine Learning (ML) workflows that will run on all indexed content.

The ML process is critically important and is responsible for:

• Optimizing search query understanding and spellcheck.
• Understanding synonyms, acronyms, and semantics used in documents and between employees within your organization.
• Enhancing relevance rankings for search results and people suggestions.
• Enabling query suggestions, predictive text, and autocomplete.
• Training the unique language model for your organization; which is essential for operation of Glean Chat and Glean Assistant.

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Usage of Glean is not supported until the ML process has completed successfully. You should not allow users access to Glean until all ML has completed.

Check the machine learning status

The ML workflows are background processes. It is not currently possible to check the status of these inside the Glean UI.

Machine learning FAQ

Completing all required ML workflows can take two to 14 days in total, depending on:

• The amount of content that needs to be processed as part of each ML workflow.
• The GCP or AWS region that your Glean tenant was deployed to (and the tier of TPU/GPU hardware available in that region).
  • For example, using an Nvidia T4 GPU (if that is all that is supported in your elected deployment region) instead of a dedicated TPU typically increases the time required to run all ML workflows by a factor of four to six times.

No. The ML workflows must be run on a complete dataset. Hence, Glean cannot initiate the ML process until all of your data sources have been crawled and indexed.

• Search results will be significantly degraded.
• Glean Assistant and Glean Chat will not respond correctly.
• Spellcheck will be erroneous.
• Autocomplete will not function.
• Any synonyms or acronyms used within the organization will not be understood if included in a search query.