Struct RankState 

pub(super) struct RankState<RF: RankFuncCount> {
    first_key: Option<StateKey>,
    buffer: EstimatedVecDeque<StateKey>,
    func_state: RF,
    persistence_enabled: bool,
    last_output_key: Option<StateKey>,
    recover_skip_until: Option<StateKey>,
    _phantom: PhantomData<RF>,
}

Generic state for rank window functions including row_number, rank and dense_rank.

Fields

first_key: Option<StateKey>

First state key of the partition.

buffer: EstimatedVecDeque<StateKey>

State keys that are waiting to be outputted.

func_state: RF

Function-specific state.

persistence_enabled: bool

Whether persistence is enabled for this state.

last_output_key: Option<StateKey>

The key of the last output row (for snapshot).

recover_skip_until: Option<StateKey>

During recovery, skip updating func_state for rows up to and including this key.

_phantom: PhantomData<RF>

Implementations

impl<RF: RankFuncCount> RankState<RF>

pub fn new(_call: &WindowFuncCall) -> Self

fn slide_inner(&mut self) -> (i64, StateEvictHint)

fn slide_no_output_inner(&mut self) -> StateEvictHint

Trait Implementations

impl<RF: RankFuncCount + EstimateSize> EstimateSize for RankState<RF>

fn estimated_heap_size(&self) -> usize

The estimated heap size of the current struct in bytes.

fn estimated_size(&self) -> usize

where Self: Sized,

The estimated total size of the current struct in bytes, including the estimated_heap_size and the size of Self.

impl<RF: RankFuncCount> WindowState for RankState<RF>

fn append(&mut self, key: StateKey, _args: SmallVec<[Datum; 2]>)

Append a new input row to the state. The key is expected to be increasing.

fn curr_window(&self) -> StatePos<'_>

Get the current window frame position.

fn is_empty(&self) -> bool

Whether no row is retained in the state.

fn slide(&mut self) -> Result<(Datum, StateEvictHint)>

Slide the window frame forward and collect the output and evict hint. Similar to Iterator::next.

fn slide_no_output(&mut self) -> Result<StateEvictHint>

Slide the window frame forward and collect the evict hint. Don’t calculate the output if possible.

fn enable_persistence(&mut self)

Enable persistence for this window state. When enabled, the state may return CanEvict hints and should support snapshot/restore.

fn snapshot(&self) -> Option<WindowStateSnapshot>

Create a snapshot of the current state for persistence. Returns None if the state doesn’t support persistence.

fn restore(&mut self, snapshot: WindowStateSnapshot) -> Result<()>

Restore the state from a snapshot. Called during recovery before replaying rows.

fn readiness(&self) -> Readiness

Get the readiness of the current window, given that the rows are appended in the order of the order key, so no future row is less than the last one. Unlike StatePos::is_ready, which is conservative and must not change for the recovery of existing jobs, this is exact.