no reduntant clone of field

src/daft-csv/src/read.rs

@@ -7,11 +7,7 @@ use arrow2::{
 use async_compat::{Compat, CompatExt};
 use common_error::{DaftError, DaftResult};
 use csv_async::AsyncReader;
-use daft_core::{
-    schema::{Schema, SchemaRef},
-    utils::arrow::cast_array_for_daft_if_needed,
-    Series,
-};
+use daft_core::{schema::Schema, utils::arrow::cast_array_for_daft_if_needed, Series};
 use daft_dsl::optimization::get_required_columns;
 use daft_io::{get_runtime, GetResult, IOClient, IOStatsRef};
 use daft_table::Table;
@@ -155,16 +151,16 @@ fn assert_stream_send<'u, R>(
 
 // Parallel version of table concat
 // get rid of this once Table APIs are parallel
-fn parallel_table_concat(tables: &[Table]) -> DaftResult<Table> {
+fn tables_concat(mut tables: Vec<Table>) -> DaftResult<Table> {
     if tables.is_empty() {
         return Err(DaftError::ValueError(
             "Need at least 1 Table to perform concat".to_string(),
         ));
     }
     if tables.len() == 1 {
-        return Ok((*tables.first().unwrap()).clone());
+        return Ok(tables.pop().unwrap());
     }
-    let first_table = tables.first().unwrap();
+    let first_table = tables.pop().unwrap();
 
     let first_schema = first_table.schema.as_ref();
     for tab in tables.iter().skip(1) {
@@ -186,7 +182,7 @@ fn parallel_table_concat(tables: &[Table]) -> DaftResult<Table> {
             Series::concat(series_to_cat.as_slice())
         })
         .collect::<DaftResult<Vec<_>>>()?;
-    Table::new(first_table.schema.clone(), new_series)
+    Table::new(first_table.schema, new_series)
 }
 
 async fn read_csv_single_into_table(
@@ -204,7 +200,6 @@ async fn read_csv_single_into_table(
 
     let limit = convert_options.as_ref().and_then(|opts| opts.limit);
 
-    let mut remaining_rows = limit.map(|limit| limit as i64);
     let include_columns = convert_options
         .as_ref()
         .and_then(|opts| opts.include_columns.clone());
@@ -255,17 +250,17 @@ async fn read_csv_single_into_table(
     let schema_fields = if let Some(include_columns) = &include_columns {
         let field_map = fields
             .iter()
-            .map(|field| (field.name.clone(), field.clone()))
-            .collect::<HashMap<String, Field>>();
+            .map(|field| (field.name.as_str(), field))
+            .collect::<HashMap<&str, &Field>>();
         include_columns
             .iter()
-            .map(|col| field_map[col].clone())
+            .map(|col| field_map[col.as_str()].clone())
             .collect::<Vec<_>>()
     } else {
         fields
     };
 
-    let schema: arrow2::datatypes::Schema = schema_fields.clone().into();
+    let schema: arrow2::datatypes::Schema = schema_fields.into();
     let schema = Arc::new(Schema::try_from(&schema)?);
 
     let filtered_tables = assert_stream_send(tables.map_ok(move |table| {
@@ -280,6 +275,7 @@ async fn read_csv_single_into_table(
             table
         }
     }));
+    let mut remaining_rows = limit.map(|limit| limit as i64);
     let collected_tables = filtered_tables
         .try_take_while(|result| {
             match (result, remaining_rows) {
@@ -304,7 +300,7 @@ async fn read_csv_single_into_table(
         return Table::empty(Some(schema));
     }
     // // TODO(Clark): Don't concatenate all chunks from a file into a single table, since MicroPartition is natively chunked.
-    let concated_table = parallel_table_concat(&collected_tables)?;
+    let concated_table = tables_concat(collected_tables)?;
     if let Some(limit) = limit && concated_table.len() > limit {
         // apply head incase that last chunk went over limit
         concated_table.head(limit)
@@ -409,17 +405,11 @@ async fn read_csv_single_into_stream(
         fields_to_projection_indices(&schema.fields, &convert_options.include_columns);
 
     let fields = schema.fields;
-    let fields_subset = projection_indices
-        .iter()
-        .map(|i| fields.get(*i).unwrap().into())
-        .collect::<Vec<daft_core::datatypes::Field>>();
-    let read_schema = daft_core::schema::Schema::new(fields_subset)?;
     let stream = parse_into_column_array_chunk_stream(
         read_stream,
         Arc::new(fields.clone()),
         projection_indices,
-        Arc::new(read_schema),
-    );
+    )?;
 
     Ok((stream, fields))
 }
@@ -486,18 +476,24 @@ fn parse_into_column_array_chunk_stream(
     stream: impl ByteRecordChunkStream + Send,
     fields: Arc<Vec<arrow2::datatypes::Field>>,
     projection_indices: Arc<Vec<usize>>,
-    read_schema: SchemaRef,
-) -> impl TableStream + Send {
+) -> DaftResult<impl TableStream + Send> {
     // Parsing stream: we spawn background tokio + rayon tasks so we can pipeline chunk parsing with chunk reading, and
     // we further parse each chunk column in parallel on the rayon threadpool.
+
+    let fields_subset = projection_indices
+        .iter()
+        .map(|i| fields.get(*i).unwrap().into())
+        .collect::<Vec<daft_core::datatypes::Field>>();
+    let read_schema = Arc::new(daft_core::schema::Schema::new(fields_subset)?);
     let read_daft_fields = Arc::new(
         read_schema
             .fields
             .values()
             .map(|f| Arc::new(f.clone()))
             .collect::<Vec<_>>(),
     );
-    stream.map_ok(move |record| {
+
+    Ok(stream.map_ok(move |record| {
         let (fields, projection_indices) = (fields.clone(), projection_indices.clone());
         let read_schema = read_schema.clone();
         let read_daft_fields = read_daft_fields.clone();
@@ -528,7 +524,7 @@ fn parse_into_column_array_chunk_stream(
             recv.await.context(super::OneShotRecvSnafu {})?
         })
         .context(super::JoinSnafu {})
-    })
+    }))
 }
 
 fn fields_to_projection_indices(