Struct Timestamp 

pub struct Timestamp(/* private fields */);

A logical timestamp marking a point in a database’s commit history.

Timestamps are issued by the database as a strictly increasing sequence. Timestamp::ZERO is the timestamp of the empty database before any commit; a reader that begins against an empty database reads at ZERO and sees nothing. The first commit is stamped 1, the next 2, and so on.

The type is Copy and totally ordered, so comparing visibility is a single integer compare on the hot read path.

Examples

use txn_db::Timestamp;

let t = Timestamp::ZERO;
assert_eq!(t.get(), 0);
assert!(Timestamp::ZERO < Timestamp::from_raw(1));

Implementations

impl Timestamp

pub const ZERO: Timestamp

The timestamp of the empty database, before any transaction has committed. A snapshot taken at ZERO observes no keys.

pub const fn from_raw(value: u64) -> Self

Wrap a raw counter value as a timestamp.

This is the inverse of Timestamp::get and exists for tests, serialization of the commit log, and custom VersionStore implementations that persist timestamps. Application code rarely constructs timestamps directly — the database issues them.

Examples

use txn_db::Timestamp;

let ts = Timestamp::from_raw(42);
assert_eq!(ts.get(), 42);

pub const fn get(self) -> u64

The raw counter value behind this timestamp.

Examples

use txn_db::Timestamp;

assert_eq!(Timestamp::from_raw(7).get(), 7);

Trait Implementations

impl Clone for Timestamp

fn clone(&self) -> Timestamp

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Timestamp

impl Debug for Timestamp

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

Formats the value using the given formatter.

impl Display for Timestamp

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

Formats the value using the given formatter.

impl Eq for Timestamp

impl Hash for Timestamp

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Timestamp

fn cmp(&self, other: &Timestamp) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Timestamp

fn eq(&self, other: &Timestamp) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Timestamp

fn partial_cmp(&self, other: &Timestamp) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Timestamp