Bulk loader: pre-allocate some buffers

lib/src/storage/mod.rs

@@ -21,7 +21,7 @@ use std::collections::VecDeque;
 use std::collections::{HashMap, HashSet};
 use std::error::Error;
 #[cfg(not(target_family = "wasm"))]
-use std::mem::take;
+use std::mem::{swap, take};
 #[cfg(not(target_family = "wasm"))]
 use std::path::{Path, PathBuf};
 #[cfg(not(target_family = "wasm"))]
@@ -1266,6 +1266,7 @@ impl StorageBulkLoader {
                     &done_counter,
                     &mut done_and_displayed_counter,
                     num_threads,
+                    batch_size,
                 )?;
             }
         }
@@ -1275,6 +1276,7 @@ impl StorageBulkLoader {
             &done_counter,
             &mut done_and_displayed_counter,
             num_threads,
+            batch_size,
         )?;
         for thread in threads {
             thread.join().unwrap()?;
@@ -1290,6 +1292,7 @@ impl StorageBulkLoader {
         done_counter: &Arc<AtomicU64>,
         done_and_displayed_counter: &mut u64,
         num_threads: usize,
+        batch_size: usize,
     ) -> Result<(), StorageError> {
         self.on_possible_progress(done_counter, done_and_displayed_counter);
         // We avoid to have too many threads
@@ -1299,11 +1302,12 @@ impl StorageBulkLoader {
                 self.on_possible_progress(done_counter, done_and_displayed_counter);
             }
         }
-        let buffer = take(buffer);
+        let mut buffer_to_load = Vec::with_capacity(batch_size);
+        swap(buffer, &mut buffer_to_load);
         let storage = self.storage.clone();
         let done_counter_clone = done_counter.clone();
         threads.push_back(spawn(move || {
-            FileBulkLoader::new(storage).load(buffer, &done_counter_clone)
+            FileBulkLoader::new(storage, batch_size).load(buffer_to_load, &done_counter_clone)
         }));
         self.on_possible_progress(done_counter, done_and_displayed_counter);
         Ok(())
@@ -1332,21 +1336,17 @@ struct FileBulkLoader {
 
 #[cfg(not(target_family = "wasm"))]
 impl FileBulkLoader {
-    fn new(storage: Storage) -> Self {
+    fn new(storage: Storage, batch_size: usize) -> Self {
         Self {
             storage,
-            id2str: HashMap::default(),
-            quads: HashSet::default(),
-            triples: HashSet::default(),
+            id2str: HashMap::with_capacity(3 * batch_size),
+            quads: HashSet::with_capacity(batch_size),
+            triples: HashSet::with_capacity(batch_size),
             graphs: HashSet::default(),
         }
     }
 
-    fn load(
-        &mut self,
-        quads: impl IntoIterator<Item = Quad>,
-        counter: &AtomicU64,
-    ) -> Result<(), StorageError> {
+    fn load(&mut self, quads: Vec<Quad>, counter: &AtomicU64) -> Result<(), StorageError> {
         self.encode(quads)?;
         let size = self.triples.len() + self.quads.len();
         self.save()?;
@@ -1354,7 +1354,7 @@ impl FileBulkLoader {
         Ok(())
     }
 
-    fn encode(&mut self, quads: impl IntoIterator<Item = Quad>) -> Result<(), StorageError> {
+    fn encode(&mut self, quads: Vec<Quad>) -> Result<(), StorageError> {
         for quad in quads {
             let encoded = EncodedQuad::from(quad.as_ref());
             if quad.graph_name.is_default_graph() {