Struct KeyExpiryManager

pub struct KeyExpiryManager {
    event_ts_to_key: BTreeMap<i64, BTreeSet<Row>>,
    key_expiration_duration: Option<i64>,
    event_timestamp_from_row: Option<ScalarExpr>,
}

Determine when should a key expire according to it’s event timestamp in key.

If a key is expired, any future updates to it should be ignored.

Note that key is expired by it’s event timestamp (contained in the key), not by the time it’s inserted (system timestamp).

Fields

event_ts_to_key: BTreeMap<i64, BTreeSet<Row>>

A map from event timestamp to key, used for expire keys.

key_expiration_duration: Option<i64>

Duration after which a key is considered expired, and will be removed from state

event_timestamp_from_row: Option<ScalarExpr>

Expression to get timestamp from key row

Implementations

impl KeyExpiryManager

pub fn new( key_expiration_duration: Option<i64>, event_timestamp_from_row: Option<ScalarExpr>, ) -> Self

pub fn extract_event_ts(&self, row: &Row) -> Result<Option<i64>, EvalError>

Extract event timestamp from key row.

If no expire state is set, return None.

pub fn compute_expiration_timestamp(&self, now: i64) -> Option<i64>

Return timestamp that should be expired by the time now by compute now - expiration_duration

pub fn get_expire_duration_and_update_event_ts( &mut self, now: i64, row: &Row, ) -> Result<Option<i64>, EvalError>

Update the event timestamp to key mapping.

• If given key is expired by now (that is less than now - expiry_duration), return the amount of time it’s expired.
• If it’s not expired, return None

pub fn get_expire_duration( &self, now: i64, row: &Row, ) -> Result<Option<i64>, EvalError>

Get the expire duration of a key, if it’s expired by now.

Return None if the key is not expired

pub fn remove_expired_keys( &mut self, now: i64, ) -> Option<impl Iterator<Item = Row>>

Remove expired keys from the state, and return an iterator of removed keys with event_ts less than expire time (i.e. now - key_expiration_duration).

Trait Implementations

impl Clone for KeyExpiryManager

fn clone(&self) -> KeyExpiryManager

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for KeyExpiryManager

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

Formats the value using the given formatter.

impl GetSize for KeyExpiryManager

fn get_heap_size(&self) -> usize

Determines how many bytes this object occupies inside the heap.

fn get_stack_size() -> usize

Determines how may bytes this object occupies inside the stack.

fn get_heap_size_with_tracker<T>(&self, tracker: T) -> (usize, T)

where T: GetSizeTracker,

Determines how many bytes this object occupies inside the heap while using a tracker.

fn get_size(&self) -> usize

Determines the total size of the object.

fn get_size_with_tracker<T>(&self, tracker: T) -> (usize, T)

where T: GetSizeTracker,

Determines the total size of the object while using a tracker.

impl Ord for KeyExpiryManager

fn cmp(&self, other: &KeyExpiryManager) -> 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 KeyExpiryManager

fn eq(&self, other: &KeyExpiryManager) -> 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 KeyExpiryManager

fn partial_cmp(&self, other: &KeyExpiryManager) -> 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 Eq for KeyExpiryManager

impl StructuralPartialEq for KeyExpiryManager