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Applies to: Embedded ✅, Enterprise ✅ Every write keeps the version before it, which is what makes time travel possible. Cleanup is what ends that: pruning versions older than a retention window, and the files that only those versions referenced.
Enterprise job type: cleanup. Distinct from compact: compaction merges files, cleanup removes them. optimize() in LanceDB Embedded runs both in one call; Enterprise schedules them as separate jobs, and runs cleanup only when the deployment’s configuration enables it.

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Retention

cleanup_older_than defaults to 7 days. Versions older than that are removed, along with the files only they referenced. In LanceDB Enterprise, the retention period comes from its configuration instead. The latest version is never removed, whatever you pass. timedelta(0) makes every older version eligible for removal, but cleanup still keeps tagged versions, as the warning below describes.
Pruning is what makes time travel finite: an eligible version outside the retention window is gone. Cleanup keeps a version, whatever its age, when it is:
  • the latest version;
  • a tagged version.
To keep a version recoverable, tag it, subject to the policy below, or keep the window wide enough to cover it.Under the default policy, a tag can also stop cleanup. When a tagged version is older than the window and is not the latest, cleanup refuses to run: it raises an error naming the tag and prunes nothing. To let it proceed, move the tag to a version inside the window, delete the tag, or widen the window.A tag on the latest version does not stop cleanup. But optimize() compacts before it prunes, and compacting commits a new version whenever it merges files, so a tag on what was the latest version can become an older one by the time cleanup runs. optimize() then raises after compacting, and its index update does not run.Enterprise background cleanup keeps tagged snapshots while pruning unrelated expired versions. If you rely on reading untagged old versions, set the window to cover the range you need before running this, not after.

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Managed blob objects

Managed blobs store out-of-line payloads under the table’s _blobs/ directory. Cleanup follows the references from retained snapshots, including protected tags, before selecting objects for deletion. Replacing a blob or deleting a row makes its old payload eligible only after no retained snapshot references it. Cleanup removes whole objects. If a packed object contains several blobs, it remains while any of them is live. Compaction preserves Managed payload objects rather than copying their bytes, so compaction alone does not reclaim the unused portion of a packed object. Use table maintenance to remove Managed objects; deleting _blobs/ files directly can corrupt current or historical snapshots. Upgrade all clients and maintenance workers to a version that understands Managed blobs before using them, and reopen handles created before that upgrade. For LanceDB Embedded tables, optimize() performs compaction and cleanup. Enterprise runs these as background jobs; Python tables connected to Enterprise do not support optimize(). See Intelligent Auto-Maintenance for the Enterprise path.

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Disk usage does not drop immediately

Compaction writes new, merged files before the old ones are removed, so disk usage can rise before it falls. Space is reclaimed only when cleanup prunes the versions that referenced the superseded files. If you need to reclaim space aggressively in the embedded library, shorten the retention window rather than waiting for the default:

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Files from failed transactions

A write that fails partway can leave files that look like an operation still in progress. Cleanup will not remove them until they are at least seven days old, because it cannot tell them apart from a live write.
This option belongs to optimize() in the embedded library. A deployment’s cleanup jobs never set it.
delete_unverified=True removes them regardless of age. Only set it when you can guarantee no other process is writing to the table. Otherwise it can delete files belonging to a write that is genuinely in progress, and corrupt the table.

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What to read next

Compaction

Merging small files, the other half of optimize().

Intelligent Auto-Maintenance

How Enterprise decides to run cleanup without a call from you.