Struct ChangeRequest 

pub struct ChangeRequest {
    pub table: String,
    pub from_snapshot: Option<i64>,
    pub to_snapshot: Option<i64>,
    pub columns: Vec<String>,
    pub filter: Option<RowFilter>,
    pub net_changes: bool,
    pub identity: Vec<String>,
}

What a caller asks a CdcBackend for.

columns and filter are the pushdown half: they narrow what the CDC read produces, exactly as crate::source::TableSpec does for a snapshot read. Before this existed, SyncMode::Cdc was full-width by construction — SELECT * from the changelog view / an unprojected read_changelog — so the projection that landed for SyncMode::Full did not reach the CDC path at all.

Fields

table: String

Fully qualified table name as the engine sees it.

from_snapshot: Option<i64>

Exclusive lower bound: the last snapshot/version already applied. None = from the beginning of the table’s history.

to_snapshot: Option<i64>

Inclusive upper bound. None = the table’s current snapshot/version.

columns: Vec<String>

The projection. Empty = every column (the pre-pushdown behaviour). The changelog metadata columns are always retained regardless.

filter: Option<RowFilter>

A row predicate applied to the change rows. None = no filter.

net_changes: bool

Collapse intermediate states so the window reports the net effect per row identity (Iceberg net_changes => true; Spark 4.2 netChanges).

identity: Vec<String>

Identity columns used to pair pre/post-images in fold_updates. Empty leaves update_before / update_after as separate rows.

Implementations

impl ChangeRequest

pub fn new(table: impl Into<String>, from: Option<i64>) -> Self

A window over table from from (exclusive) to the current snapshot.

pub fn with_columns(self, columns: Vec<String>) -> Self

Narrow the read to columns (empty leaves it unprojected).

pub fn with_filter(self, filter: Option<RowFilter>) -> Self

Push filter into the change read.

pub fn to(self, to: Option<i64>) -> Self

Set the upper bound (inclusive).

pub fn with_identity(self, identity: Vec<String>) -> Self

Pair pre/post-images on these identity columns.

pub fn engine_columns(&self) -> Vec<String>

The projection as the engine must see it: the asked-for columns plus every changelog metadata column, which must survive so the encoder can read op / snapshot / ts. Empty stays empty (= all columns).

Trait Implementations

impl Clone for ChangeRequest

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ChangeRequest

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

Formats the value using the given formatter.

impl Default for ChangeRequest

fn default() -> Self

Returns the “default value” for a type.