Tools

This page documents Cobble maintenance tools that are used outside an active writer Db.

Prune Shard Snapshot

prune_shard_snapshot removes one shard snapshot manifest and releases files that are only referenced by that snapshot.

Rust:

use cobble::{Config, prune_shard_snapshot};

let removed = prune_shard_snapshot(config, db_id, snapshot_id)?;
// removed == true: snapshot existed and was pruned
// removed == false: snapshot did not exist

Notes

• This is a maintenance tool API, not a Db instance method.
• It is intended for out-of-band lifecycle managers (for example, a global committer).
• If files are still referenced by other snapshots, those files are retained.

Recommended Writer DB Configuration (with external pruning)

When writer shards are managed by an external global lifecycle component, configure writer DBs as:

• snapshot_only_track: true — writer only tracks snapshots and does not run DB-side retention expiration.
• snapshot_disable_incremental_base_link: true — disable incremental manifest base linking for writer snapshots.
• snapshot_retention: null — do not enable local retention on writer shards.

This keeps snapshot cleanup ownership in the external pruning workflow.