Use SQLite as default unless existing mlruns data is detected by harupy · Pull Request #18497 · mlflow/mlflow

harupy · 2025-10-24T06:19:26Z

Related Issues/PRs

What changes are proposed in this pull request?

This PR changes the default tracking URI from file-based storage (./mlruns) to SQLite database (sqlite:///mlflow.db).

Backward Compatibility: Existing mlruns directories with experiment data are automatically detected and continue using file store, ensuring seamless migration for existing users.

How is this PR tested?

Existing unit/integration tests
New tests for backward compatibility detection

Does this PR require documentation update?

Yes. I've updated:
- Examples
- API references
- Instructions

Release Notes

Is this a user-facing change?

Yes. Give a description of this change to be included in the release notes for MLflow users.

Breaking Change: The default tracking URI has been changed from file-based storage (./mlruns) to SQLite database (sqlite:///mlflow.db). Users who rely on the default behavior will now use SQLite instead of file-based storage. To revert to the previous behavior, set MLFLOW_TRACKING_URI=./mlruns or use mlflow.set_tracking_uri("./mlruns").

What component(s), interfaces, languages, and integrations does this PR affect?

Components

area/tracking: Tracking Service, tracking client APIs, autologging
area/build: Build and test infrastructure for MLflow

How should the PR be classified in the release notes? Choose one:

rn/breaking-change - The PR will be mentioned in the "Breaking Changes" section

Should this PR be included in the next patch release?

Yes should be selected for bug fixes, documentation updates, and other small changes. No should be selected for new features and larger changes. If you're unsure about the release classification of this PR, leave this unchecked to let the maintainers decide.

What is a minor/patch release?

Minor release: a release that increments the second part of the version number (e.g., 1.2.0 -> 1.3.0).
Bug fixes, doc updates and new features usually go into minor releases.
Patch release: a release that increments the third part of the version number (e.g., 1.2.0 -> 1.2.1).
Bug fixes and doc updates usually go into patch releases.
Yes (this PR will be cherry-picked and included in the next patch release)
No (this PR will be included in the next minor release)

github-actions · 2025-10-24T06:33:12Z

Documentation preview for 34e5bc4 is available at:

https://pr-18497--mlflow-docs-preview.netlify.app/docs/latest/

More info

Ignore this comment if this PR does not change the documentation.
The preview is updated when a new commit is pushed to this PR.
This comment was created by this workflow run.
The documentation was built by this workflow run.

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

B-Step62 · 2025-11-18T07:50:24Z

mlflow/store/tracking/file_store.py

+            "See https://github.com/mlflow/mlflow/issues/18534 for feedback and how to migrate "
+            "existing data.",


Ideally we should add both. Can we add a notable warning box in https://mlflow.org/docs/latest/self-hosting/ about the defauilt change and link to Github issue for details? Can we do that in a follow-up? I think we need some doc clean up anyway (e.g., remove explicit '--backend-store-uri sqlite:///mlflow.db' specification in some examples)

mlflow/store/tracking/file_store.py

mlflow/tracking/_tracking_service/utils.py

harupy · 2025-11-18T08:06:25Z

/resolve

🚀 Resolve workflow started

✅ Workflow completed successfully.

Claude Output

Summary

I successfully resolved the unresolved PR review comments for PR #18497. Here's what was addressed:

Changes Made:

mlflow/store/tracking/file_store.py:220 - Changed deprecation warning wording from "is deprecated" to "will be deprecated" to use a softer, less assertive tone as suggested by the reviewer.
mlflow/tracking/_tracking_service/utils.py:30 - Enhanced the docstring for _has_existing_mlruns_data() to explain the backward compatibility context: the function checks for existing mlruns data so the default tracking URI can remain as file-based storage for existing workflows.

Skipped:

One review thread had an explicit instruction from the reviewer (harupy) saying "Claude: ignore this review comment" - this was correctly skipped as it was marked for follow-up work.

Commit:

All changes have been committed locally with DCO sign-off (commit: 50739c5). Pre-commit hooks ran successfully and passed all checks. The changes are ready but have NOT been pushed to the remote repository as per instructions.

- Change deprecation warning from "is deprecated" to "will be deprecated" for softer tone - Add context to _has_existing_mlruns_data() docstring explaining backward compatibility purpose 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> Signed-off-by: mlflow-app[bot] <mlflow-app[bot]@users.noreply.github.com>

- Change deprecation warning from "is deprecated" to "will be deprecated" - Update terminology from "model registry backend" to "tracking backend" - Update tests to match the new warning message format - Improve warning text clarity by restructuring the migration guidance 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

mlflow/cli/__init__.py

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

serena-ruan

LGTM!

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

B-Step62

LGTM!

Updates self-hosting documentation to reflect that SQLite is now the default tracking backend (changed in MLflow 3.7 via mlflow#18497). Changes: - Add warning box in self-hosting overview about default change - Update quickstart examples to remove explicit SQLite flags - Update tracking server documentation with new defaults - Add guidance for existing users (auto-detection) and new users Addresses: mlflow#18497 (comment) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

…#18497) Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Signed-off-by: mlflow-app[bot] <mlflow-app[bot]@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: mlflow-app[bot] <mlflow-app[bot]@users.noreply.github.com>

…#18497) Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Signed-off-by: mlflow-app[bot] <mlflow-app[bot]@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: mlflow-app[bot] <mlflow-app[bot]@users.noreply.github.com> Signed-off-by: Tian Lan <sky.blue266000@gmail.com>

github-actions bot added the rn/none List under Small Changes in Changelogs. label Oct 24, 2025

harupy force-pushed the test-default-sqlite branch from 4a7be95 to 98020fb Compare November 14, 2025 09:03

harupy changed the title ~~Change defualt tracking_uri to sqlite~~ Change default tracking_uri to sqlite Nov 14, 2025

harupy added 5 commits November 17, 2025 14:39

Change defualt tracking_uri to sqlite

bced1b9

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

Fix

f5530ff

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

Update example

dffacd7

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

test

1c31661

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

Fix failed tests

2e12c65

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

harupy force-pushed the test-default-sqlite branch from e29e143 to 2e12c65 Compare November 17, 2025 05:39

Fix failed tests

9d8af7f

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

harupy changed the title ~~Change default tracking_uri to sqlite~~ Change default tracking URI to sqlite Nov 17, 2025

harupy changed the title ~~Change default tracking URI to sqlite~~ Change default tracking URI to SQLite and improve TypeScript tests Nov 17, 2025

harupy changed the title ~~Change default tracking URI to SQLite and improve TypeScript tests~~ Change default tracking URI to SQLite Nov 17, 2025

Remove commented out code

339fa2f

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

harupy added the team-review Trigger a team review request label Nov 17, 2025

github-actions bot removed the area/tracing MLflow Tracing and its integrations label Nov 17, 2025

github-actions bot requested review from B-Step62, BenWilson2, TomeHirata, WeichenXu123, daniellok-db, kevin-lyn, serena-ruan and xq-yin November 17, 2025 06:25

B-Step62 reviewed Nov 18, 2025

View reviewed changes

harupy mentioned this pull request Nov 18, 2025

Remove --backend-store-uri from docs #18884

Closed

harupy requested a review from B-Step62 November 18, 2025 08:10

serena-ruan reviewed Nov 18, 2025

View reviewed changes

mlflow/cli/__init__.py Show resolved Hide resolved

harupy requested a review from serena-ruan November 18, 2025 09:16

serena-ruan reviewed Nov 18, 2025

View reviewed changes

mlflow/cli/__init__.py Show resolved Hide resolved

Echo URIs if unspecified

3ec5671

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

serena-ruan approved these changes Nov 18, 2025

View reviewed changes

Clean up redundant comment

34e5bc4

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com>

B-Step62 approved these changes Nov 18, 2025

View reviewed changes

harupy enabled auto-merge November 18, 2025 10:32

harupy added this pull request to the merge queue Nov 18, 2025

Merged via the queue into mlflow:master with commit aae3db2 Nov 18, 2025
47 checks passed

harupy deleted the test-default-sqlite branch November 18, 2025 10:48

harupy mentioned this pull request Nov 18, 2025

Document SQLite as default tracking backend in MLflow 3.7 #18887

Merged

8 tasks

harupy mentioned this pull request Nov 19, 2025

Improve file store deprecation warning messages #18900

Merged

9 tasks

samwithwicky mentioned this pull request Dec 28, 2025

[BUG] mlflow creating mlruns directory in serve-artifacts mode #19658

Closed

11 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Use SQLite as default unless existing mlruns data is detected#18497

Use SQLite as default unless existing mlruns data is detected#18497
harupy merged 17 commits intomlflow:masterfrom
harupy:test-default-sqlite

harupy commented Oct 24, 2025 •

edited

Loading

Uh oh!

github-actions bot commented Oct 24, 2025 •

edited

Loading

Uh oh!

B-Step62 Nov 18, 2025

Uh oh!

Uh oh!

Uh oh!

Uh oh!

harupy commented Nov 18, 2025 •

edited by github-actions bot

Loading

Summary

Changes Made:

Skipped:

Commit:

Uh oh!

Uh oh!

Uh oh!

serena-ruan left a comment

Uh oh!

B-Step62 left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

		"See https://github.com/mlflow/mlflow/issues/18534 for feedback and how to migrate "
		"existing data.",

Conversation

harupy commented Oct 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Related Issues/PRs

What changes are proposed in this pull request?

How is this PR tested?

Does this PR require documentation update?

Release Notes

Is this a user-facing change?

What component(s), interfaces, languages, and integrations does this PR affect?

How should the PR be classified in the release notes? Choose one:

Should this PR be included in the next patch release?

Uh oh!

github-actions bot commented Oct 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

B-Step62 Nov 18, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

harupy commented Nov 18, 2025 • edited by github-actions bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Changes Made:

Skipped:

Commit:

Uh oh!

Uh oh!

Uh oh!

serena-ruan left a comment

Choose a reason for hiding this comment

Uh oh!

B-Step62 left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

harupy commented Oct 24, 2025 •

edited

Loading

github-actions bot commented Oct 24, 2025 •

edited

Loading

harupy commented Nov 18, 2025 •

edited by github-actions bot

Loading