[GitHub] [arrow] jorgecarleitao commented on a change in pull request #8428: ARROW-10251: [Rust] [DataFusion] MemTable::load() now loads partitions in parallel

[GitBox <gi...@apache.org>]

jorgecarleitao commented on a change in pull request #8428:
URL: https://github.com/apache/arrow/pull/8428#discussion_r502821593



##########
File path: rust/datafusion/src/datasource/memory.rs
##########
@@ -59,13 +61,22 @@ impl MemTable {
     pub async fn load(t: &dyn TableProvider, batch_size: usize) -> Result<Self> {
         let schema = t.schema();
         let exec = t.scan(&None, batch_size)?;
+        let partition_count = exec.output_partitioning().partition_count();
+
+        let mut tasks = Vec::with_capacity(partition_count);
+        for partition in 0..partition_count {
+            let exec = exec.clone();
+            let task: JoinHandle<Result<Vec<RecordBatch>>> = task::spawn(async move {
+                let it = exec.execute(partition).await?;
+                Ok(it.into_iter().collect::<ArrowResult<Vec<RecordBatch>>>()?)

Review comment:
       ```suggestion
                   it.into_iter().collect::<ArrowResult<Vec<RecordBatch>>>()
   ```

##########
File path: rust/datafusion/src/datasource/memory.rs
##########
@@ -59,13 +61,22 @@ impl MemTable {
     pub async fn load(t: &dyn TableProvider, batch_size: usize) -> Result<Self> {
         let schema = t.schema();
         let exec = t.scan(&None, batch_size)?;
+        let partition_count = exec.output_partitioning().partition_count();
+
+        let mut tasks = Vec::with_capacity(partition_count);
+        for partition in 0..partition_count {
+            let exec = exec.clone();
+            let task: JoinHandle<Result<Vec<RecordBatch>>> = task::spawn(async move {
+                let it = exec.execute(partition).await?;
+                Ok(it.into_iter().collect::<ArrowResult<Vec<RecordBatch>>>()?)
+            });
+            tasks.push(task)
+        }
 
-        let mut data: Vec<Vec<RecordBatch>> =
-            Vec::with_capacity(exec.output_partitioning().partition_count());
-        for partition in 0..exec.output_partitioning().partition_count() {
-            let it = exec.execute(partition).await?;
-            let partition_batches = it.into_iter().collect::<ArrowResult<Vec<_>>>()?;
-            data.push(partition_batches);
+        let mut data: Vec<Vec<RecordBatch>> = Vec::with_capacity(partition_count);
+        for task in tasks {
+            let result = task.await.unwrap()?;

Review comment:
       ```suggestion
               let result = task.await.expect("To have some data on every recordBatch")?;
   ```




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