Struct PostgresCancelToken 

pub struct PostgresCancelToken { /* private fields */ }

A token that can be used to cancel a running query on a PgConnection.

Obtained via PgConnection::cancel_token. Cancellation is a best-effort signal: the server may have already finished processing the query by the time the cancel request arrives, and the cancel request itself is sent over a separate TCP connection with no acknowledgement.

This type is Send + Sync and can be passed to other tasks.

Implementations

impl PostgresCancelToken

pub async fn cancel_query<T>(&self, tls: T) -> Result<(), PgError>

where T: MakeTlsConnect<Socket> + Clone,

Send a cancel request to the PostgreSQL server.

Uses tls to open the temporary cancel connection. Pass tokio_postgres::NoTls for unencrypted connections, or the same TLS connector used when establishing the main connection for encrypted ones.

Returns Ok(()) when the cancel request was sent (not when it was acted upon — there is no acknowledgement in the PostgreSQL wire protocol for cancel requests).

Errors

Returns PgError::Connection if the cancel connection could not be established or the cancel packet could not be sent.

Example

use oxisql_postgres::{PgConnection, TlsMode};

let conn = PgConnection::connect("host=localhost user=postgres", TlsMode::Disabled).await?;
let token = conn.cancel_token().await;
// In another task:
token.cancel_query(tokio_postgres::NoTls).await?;