LSIF: Fast and precise code intelligence

LSIF is a file format for precomputed code intelligence data. It provides fast and precise code intelligence but needs to be periodically generated and uploaded to your Sourcegraph instance. LSIF is opt-in: repositories for which you have not uploaded LSIF data will continue to use the built-in code intelligence.

Precise code intelligence using LSIF is supported in Sourcegraph 3.8 and up.

For users who have a language server deployed, LSIF will take priority over the language server when LSIF data exists for a repository.

Getting started

Follow our LSIF quickstart guide to manually generate and upload LSIF data for your repository. After you are satisfied with the result, you can upload LSIF data to a Sourcegraph instance using your existing continuous integration infrastructure, or using GitHub Actions.

Enabling LSIF on your Sourcegraph instance

Go to your global settings at https://sourcegraph.example.com/site-admin/global-settings and enable LSIF:

  "codeIntel.lsif": true

After uploading LSIF files, your Sourcegraph instance will use these files to respond to code intelligence requests (such as for hovers, definitions, and references). When LSIF data does not exist for a particular file in a repository, Sourcegraph will fall back to built-in code intelligence.

Stale code intelligence

LSIF code intelligence will be out of sync when you’re viewing a file that has changed since the LSIF data was uploaded.

Data retention policy

The bulk of LSIF data is stored on-disk, and as code intelligence data for a commit ages it becomes less useful. Sourcegraph will automatically remove the least recently uploaded data if the amount of disk space falls above a threshold. This value can be changed via the DBS_DIR_MAXIMUM_SIZE_BYTES environment variable. The default value of this variable is 10737418240, which is 1024 * 1024 * 1024 * 10 bytes, or 10 gigabytes.

Warning about uploading too much data

Global find-references is a resource-intensive operation that’s sensitive to the number of packages for which you have uploaded LSIF data into your Sourcegraph instance. Improvements to this are planned for Sourcegraph 3.10 (see the RFC).

Do not upload more than 10-40 LSIF dumps to your Sourcegraph instance or you risk harming other parts of Sourcegraph. We are working to validate its performance at scale and eliminate this concern.

Cross-repository code intelligence

Cross-repository code intelligence will only be powered by LSIF when both repositories have LSIF data. When the current file has LSIF data and the other repository doesn’t, there will be no code intelligence results (we’re working on fallback to fuzzy code intelligence for 3.10).

More about LSIF

To learn more, check out our lightning talk about LSIF from GopherCon 2019 or the introductory blog post: