Struct QueryControl 

pub struct QueryControl { /* private fields */ }

A thread-safe handle for interrupting or observing one running query. A narrow, thread-safe handle for interrupting or observing one query.

Minted by Connection::query_control. Unlike the connection itself, QueryControl is Clone + Send + Sync: DuckDB explicitly permits duckdb_interrupt and duckdb_query_progress to be called from a different thread than the one running the query — that is their entire purpose. It exposes only those two read/signal operations, never anything that would execute SQL, so it cannot create a second concurrent user of the connection.

Generation scoping

The control captures the connection’s query generation when minted. interrupt only signals DuckDB while that generation is still current; once the query completes (advancing the generation) it becomes a no-op. This makes a delayed or racing cancellation unable to interrupt a subsequent, unrelated query on the same connection.

Implementations

impl QueryControl

pub fn interrupt(&self) -> bool

Requests interruption of the query this control was minted for.

Idempotent, and a no-op once that query has finished (the generation has advanced). Returns true if the interrupt was actually signalled to DuckDB, false if it was skipped as stale.

pub fn progress(&self) -> Option<QueryProgress>

Reads the progress of the query currently running on the connection.

Returns None once the query this control was minted for has finished (the generation has advanced), so a stale control cannot report a later query’s progress as its own.

pub fn is_active(&self) -> bool

Returns true if the query this control was minted for is still current.

Trait Implementations

impl Clone for QueryControl

fn clone(&self) -> QueryControl

Returns a duplicate of the value.

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

Performs copy-assignment from source.