Struct AttemptUsage

pub struct AttemptUsage { /* private fields */ }

Usage accounted for a single transaction attempt.

Counters are incremented by Transaction as operations are issued (writes) or resolved (reads). They are always on: no instrumentation is required to get them.

A new instance is created for every attempt, see the module documentation.

The application metrics recorded with Transaction::set_custom_metric are stored here too, and are therefore per-attempt as well. Their map is allocated on first use, so a transaction that never records one pays nothing. Without a metrics consumer collecting them (typically Database::instrumented_run), they are simply dropped with the generation.

Implementations

impl AttemptUsage

pub fn new() -> Self

Starts a new, empty accounting generation, measured with the WallClock.

pub fn elapsed(&self) -> Duration

Time elapsed since the attempt started, measured with the clock the attempt was stamped with.

A clock that goes backwards yields zero rather than panicking.

pub fn bytes_read(&self) -> u64

Bytes read so far, keys and values summed.

pub fn bytes_written(&self) -> u64

Bytes written so far, keys, values and mutation parameters summed.

pub fn snapshot(&self) -> UsageSnapshot

Takes a consistent-enough copy of every counter.

Counters are read one after the other without a lock, so a snapshot taken while operations are completing may mix values from slightly different instants.

pub fn custom_metrics(&self) -> HashMap<MetricKey, u64>

The application metrics recorded during this attempt.

Trait Implementations

impl Debug for AttemptUsage

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

Formats the value using the given formatter.

impl Default for AttemptUsage

fn default() -> Self

Returns the “default value” for a type.