cancel

Best-effort asynchronous cancellation of any statement currently executing on this connection. Designed to be called from a thread OTHER than the one blocked inside a kdbc call — that is the point: higher-level code (e.g. a Kotlin coroutine cancellation handler) can interrupt a running query without waiting for it.

When the cancel takes effect the blocking call on the other thread returns with an error (typically mapped to an exception). Cancel is a request, not a guarantee.

Thread safety: safe to call concurrently with a blocking kdbc call on the same connection. NOT safe to call concurrently with close — callers must serialize cancellation with connection teardown.

Implementations: JVM delegates to java.sql.Statement.cancel on the active statement (or is a no-op if no active statement is tracked); Native delegates to the kdbc C layer's kdbc_cancel which dispatches to the driver-specific primitive (PQcancel, sqlite3_interrupt, mariadb_cancel, dpiConn_breakExecution). Default: no-op.