Struct GcStats 

pub struct GcStats {
    pub watermark: Timestamp,
    pub active_transactions: usize,
}

A snapshot of reclamation state, from Database::stats.

These two are what version reclamation is gated on, which is why they are the pair to alert on. Pruning cannot pass the oldest live snapshot, so a single forgotten transaction stops it for every record at once and chains start growing without limit again.

The signal is watermark flat while writes continue, usually alongside an active_transactions that only climbs. Neither number means much alone — a flat watermark on an idle database is just an idle database.

let db = Database::open(Config::in_memory())?;
db.register::<Account>()?;

// A transaction held open pins the watermark for everyone.
let held = db.begin();
assert_eq!(db.stats().active_transactions, 1);

drop(held);
assert_eq!(db.stats().active_transactions, 0);

Fields

watermark: Timestamp

The oldest snapshot any live transaction still reads at, or the read watermark when there are none. Versions superseded at or before this are reclaimable.

active_transactions: usize

Live transactions. A number that only grows is the leak.

Trait Implementations

impl Clone for GcStats

fn clone(&self) -> GcStats

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for GcStats

impl Debug for GcStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.