zhuqi-lucas commented on issue #16193:
URL: https://github.com/apache/datafusion/issues/16193#issuecomment-2916774947
@pepijnve It works for me, the change code is here:
```rust
tokio = { workspace = true, features = ["macros", "signal"]}
```
```rust
use arrow::array::{Int64Array, RecordBatch};
use arrow::datatypes::{DataType, Field, Fields, Schema, SchemaRef};
use datafusion::execution::{RecordBatchStream, SendableRecordBatchStream,
TaskContext};
use datafusion::functions_aggregate::sum;
use datafusion::physical_expr::aggregate::AggregateExprBuilder;
use datafusion::physical_expr::{EquivalenceProperties, Partitioning};
use datafusion::physical_plan::aggregates::{AggregateExec, AggregateMode,
PhysicalGroupBy};
use datafusion::physical_plan::execution_plan::{Boundedness, EmissionType};
use datafusion::physical_plan::{DisplayAs, DisplayFormatType, ExecutionPlan,
PlanProperties};
use datafusion::{common, physical_plan};
use futures::{Stream, StreamExt};
use std::any::Any;
use std::error::Error;
use std::fmt::Formatter;
use std::pin::Pin;
use std::sync::Arc;
use std::task::{Context, Poll};
use tokio::signal::ctrl_c;
use datafusion::prelude::SessionContext;
struct InfiniteStream {
batch: RecordBatch,
poll_count: usize,
}
impl RecordBatchStream for InfiniteStream {
fn schema(&self) -> SchemaRef {
self.batch.schema()
}
}
impl Stream for InfiniteStream {
type Item = common::Result<RecordBatch>;
fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) ->
Poll<Option<Self::Item>> {
self.poll_count += 1;
if self.poll_count % 10_000 == 0 {
println!("InfiniteStream::poll_next {} times", self.poll_count);
}
Poll::Ready(Some(Ok(self.batch.clone())))
}
}
#[derive(Debug)]
struct InfiniteExec {
batch: RecordBatch,
properties: PlanProperties,
}
impl InfiniteExec {
fn new(batch: &RecordBatch) -> Self {
InfiniteExec {
batch: batch.clone(),
properties: PlanProperties::new(
EquivalenceProperties::new(batch.schema().clone()),
Partitioning::UnknownPartitioning(1),
EmissionType::Incremental,
Boundedness::Unbounded {
requires_infinite_memory: false,
},
),
}
}
}
impl DisplayAs for InfiniteExec {
fn fmt_as(&self, _t: DisplayFormatType, f: &mut Formatter) ->
std::fmt::Result {
write!(f, "infinite")
}
}
impl ExecutionPlan for InfiniteExec {
fn name(&self) -> &str {
"infinite"
}
fn as_any(&self) -> &dyn Any {
self
}
fn schema(&self) -> SchemaRef {
self.batch.schema()
}
fn properties(&self) -> &PlanProperties {
&self.properties
}
fn children(&self) -> Vec<&Arc<dyn ExecutionPlan>> {
vec![]
}
fn with_new_children(
self: Arc<Self>,
_children: Vec<Arc<dyn ExecutionPlan>>,
) -> common::Result<Arc<dyn ExecutionPlan>> {
Ok(self.clone())
}
fn execute(
&self,
_partition: usize,
_context: Arc<TaskContext>,
) -> common::Result<SendableRecordBatchStream> {
Ok(Box::pin(InfiniteStream {
batch: self.batch.clone(),
poll_count: 0,
}))
}
}
#[tokio::test]
async fn main() -> Result<(), Box<dyn Error>> {
// 1) build session & schema & sample batch
let session_ctx = SessionContext::new();
let schema = Arc::new(Schema::new(Fields::try_from(vec![
Field::new("value", DataType::Int64, false),
])?));
let mut builder = Int64Array::builder(8192);
for v in 0..8192 {
builder.append_value(v);
}
let batch = RecordBatch::try_new(schema.clone(),
vec![Arc::new(builder.finish())])?;
// 2) set up the infinite source + aggregation
let inf = Arc::new(InfiniteExec::new(&batch));
let aggr = Arc::new(AggregateExec::try_new(
AggregateMode::Single,
PhysicalGroupBy::new(vec![], vec![], vec![]),
vec![Arc::new(
AggregateExprBuilder::new(sum::sum_udaf(), vec![Arc::new(
datafusion::physical_expr::expressions::Column::new_with_schema(
"value", &schema,
)?
)])
.schema(inf.schema())
.alias("sum")
.build()?,
)],
vec![None],
inf.clone(),
inf.schema(),
)?);
// 3) get the stream
let mut stream = physical_plan::execute_stream(aggr,
session_ctx.task_ctx())?;
println!("Running query; press Ctrl-C to cancel");
// 4) drive the stream inline in select!
let result = tokio::select! {
batch_opt = async {
loop {
if let Some(item) = stream.next().await {
break Some(item);
} else {
break None;
}
}
} => batch_opt,
_ = ctrl_c() => {
println!("Cancellation received!");
None
}
};
// 5) handle the outcome
match result {
None => println!("No result (cancelled or empty)"),
Some(Ok(batch)) => println!("Got batch with {} rows",
batch.num_rows()),
Some(Err(e)) => eprintln!("Error: {}", e),
}
println!("Exiting, stream will be dropped now");
Ok(())
}
```
Testing result, ctril c works well:
```rust
Running query; press Ctrl-C to cancel
InfiniteStream::poll_next 10000 times
InfiniteStream::poll_next 20000 times
InfiniteStream::poll_next 30000 times
InfiniteStream::poll_next 40000 times
InfiniteStream::poll_next 50000 times
Cancellation received!
No result (cancelled or empty)
Exiting, stream will be dropped now
```
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