reduce channel buffers

Author: Jan Kaul

datafusion_iceberg/src/materialized_view/delta_queries/fork_node.rs

@@ -34,7 +34,7 @@ pub fn fork_node(plan: Arc<LogicalPlan>) -> (ForkNode, ForkNode) {
     let parallelism = std::thread::available_parallelism().unwrap().get();
     let (sender, receiver): (Vec<_>, Vec<_>) = iter::repeat_n((), parallelism)
         .map(|_| {
-            let (sender, receiver) = channel(1);
+            let (sender, receiver) = channel(0);
             (
                 Arc::new(Mutex::new(Some(sender))),
                 Arc::new(Mutex::new(Some(receiver))),

iceberg-rust/src/arrow/write.rs

@@ -308,7 +308,7 @@ async fn write_parquet_files(
     equality_ids: Option<&[i32]>,
 ) -> Result<Vec<DataFile>, ArrowError> {
     let bucket = Bucket::from_path(data_location)?;
-    let (mut writer_sender, writer_reciever): (ArrowSender, ArrowReciever) = channel(1);
+    let (mut writer_sender, writer_reciever): (ArrowSender, ArrowReciever) = channel(0);
 
     // Create initial writer
     let initial_writer = create_arrow_writer(