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Cleaner

hyperfile_cleaner

Trait Cleaner 

Source 
pub trait Cleaner {
    // Required methods
    fn collect(
        &self,
        low: Cno,
        high: Cno,
    ) -> impl Future<Output = Result<(Vec<SegmentId>, Vec<SegmentId>)>> + Send;
    fn prune(
        &self,
        low: Cno,
        high: Cno,
    ) -> impl Future<Output = Result<()>> + Send;
}
Expand description

Operations supported by a hyperfile cleaner backend.

Both methods take a [low, high] range of checkpoint numbers (Cno). high == 0 is a sentinel meaning “use the latest published checkpoint (Inode::get_last_cno)”. low is inclusive; a typical value is 1 to cover the entire file history.

The range is inclusive at both ends, so low == high is valid and answered normally — which is what collect(1, 0) resolves to on a file with a single checkpoint. Only low > high is an error, and that also covers a file that has never been flushed (get_last_cno() == 0), since there is no metadata tree to walk.

What the methods report and delete is SegmentId, which names a stored object rather than a checkpoint: a checkpoint written under BlockPtrFormat::PartedSegment is several objects — <cno>.0, <cno>.1, … — and they are not reclaimable together. Under every other format an object and a checkpoint are the same thing and a SegmentId prints as the plain number.

Required Methods§

Source

fn collect( &self, low: Cno, high: Cno, ) -> impl Future<Output = Result<(Vec<SegmentId>, Vec<SegmentId>)>> + Send

Walk the metadata tree of the checkpoint identified by high (or the latest if high == 0) and return (referenced, unreferenced) lists of segment objects, the unreferenced one limited to checkpoints within [low, high].

Useful for dry-run inspection before invoking Cleaner::prune.

Source

fn prune(&self, low: Cno, high: Cno) -> impl Future<Output = Result<()>> + Send

Walk the metadata tree as in Cleaner::collect and then delete the unreferenced segment objects from the underlying store.

Errors if any individual delete batch fails; in that case previously-deleted batches stay deleted (S3 has no transactional batch). The returned error message mentions the failed object count and a sample failed key.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§