CC @krlmlr

What are the semantics of pending_query->ExecuteTask() ?

See #2797

//! Executes a single task within the query, returning whether or not the query is ready.
//! If this returns RESULT_READY, the Execute function can be called to obtain a pointer to the result.
//! If this returns RESULT_NOT_READY, the ExecuteTask function should be called again.
//! If this returns EXECUTION_ERROR, an error occurred during execution.
//! The error message can be obtained by calling GetError() on the PendingQueryResult.
PendingExecutionResult ExecuteTask();

Are there plans to bring this to the C API? I hate to be greedy, but I have wished for such a thing for interactive UI's that allow the users to get themselves into trouble with sliders and such. I suspect my C skills are not going to pass muster for a PR. Would you expect the signatures to be something like this:

duckdb_state duckdb_query_pending_init(duckdb_connection connection, const char *query, duckdb_pending_query *out) {
}

duckdb_state duckdb_query_pending_execute(duckdb_pending_query *pending, duckdb_result *out) {
}

duckdb_state duckdb_query_pending_cancel(duckdb_pending_query *pending) {
}

Are there plans to bring this to the C API? I hate to be greedy, but I have wished for such a thing for interactive UI's that allow the users to get themselves into trouble with sliders and such. I suspect my C skills are not going to pass muster for a PR. Would you expect the signatures to be something like this:

duckdb_state duckdb_query_pending_init(duckdb_connection connection, const char *query, duckdb_pending_query *out) {
}

duckdb_state duckdb_query_pending_execute(duckdb_pending_query *pending, duckdb_result *out) {
}

duckdb_state duckdb_query_pending_cancel(duckdb_pending_query *pending) {
}

I agree this would be a useful extension to the C API - I can have a go at adding this.

That would be fantastic!