try using try_map_try_init

milli/src/update/new/indexer/document_operation.rs

@@ -13,6 +13,7 @@ use super::super::items_pool::ItemsPool;
 use super::super::{CowStr, TopLevelMap};
 use super::DocumentChanges;
 use crate::documents::{DocumentIdExtractionError, PrimaryKey};
+use crate::update::new::items_pool::ParallelIteratorExt as _;
 use crate::update::new::{Deletion, Insertion, KvReaderFieldId, KvWriterFieldId, Update};
 use crate::update::{AvailableIds, IndexDocumentsMethod};
 use crate::{DocumentId, Error, FieldsIdsMap, Index, Result, UserError};
@@ -73,7 +74,12 @@ impl<'p, 'pl: 'p> DocumentChanges<'p> for DocumentOperation<'pl> {
         self,
         fields_ids_map: &mut FieldsIdsMap,
         param: Self::Parameter,
-    ) -> Result<impl IndexedParallelIterator<Item = Result<DocumentChange>> + Clone + 'p> {
+    ) -> Result<
+        impl IndexedParallelIterator<
+                Item = std::result::Result<DocumentChange, Option<crate::Error>>,
+            > + Clone
+            + 'p,
+    > {
         let (index, rtxn, primary_key) = param;
 
         let documents_ids = index.documents_ids(rtxn)?;
@@ -199,24 +205,22 @@ impl<'p, 'pl: 'p> DocumentChanges<'p> for DocumentOperation<'pl> {
         // And finally sort them
         docids_version_offsets.sort_unstable_by_key(|(_, (_, docops))| sort_function_key(docops));
 
-        Ok(docids_version_offsets.into_par_iter().map_with(
-            Arc::new(ItemsPool::new(|| index.read_txn().map_err(crate::Error::from))),
-            move |context_pool, (external_docid, (internal_docid, operations))| {
-                context_pool.with(|rtxn| {
-                    let document_merge_function = match self.index_documents_method {
-                        Idm::ReplaceDocuments => MergeDocumentForReplacement::merge,
-                        Idm::UpdateDocuments => MergeDocumentForUpdates::merge,
-                    };
+        Ok(docids_version_offsets.into_par_iter().try_map_try_init(
+            || index.read_txn().map_err(crate::Error::from),
+            move |rtxn, (external_docid, (internal_docid, operations))| {
+                let document_merge_function = match self.index_documents_method {
+                    Idm::ReplaceDocuments => MergeDocumentForReplacement::merge,
+                    Idm::UpdateDocuments => MergeDocumentForUpdates::merge,
+                };
 
-                    document_merge_function(
-                        rtxn,
-                        index,
-                        &fields_ids_map,
-                        internal_docid,
-                        external_docid.to_string(), // TODO do not clone
-                        &operations,
-                    )
-                })
+                document_merge_function(
+                    rtxn,
+                    index,
+                    &fields_ids_map,
+                    internal_docid,
+                    external_docid.to_string(), // TODO do not clone
+                    &operations,
+                )
             },
         ))
     }

milli/src/update/new/indexer/mod.rs

@@ -23,7 +23,7 @@ use crate::documents::{PrimaryKey, DEFAULT_PRIMARY_KEY};
 use crate::update::new::channel::ExtractorSender;
 use crate::update::settings::InnerIndexSettings;
 use crate::update::GrenadParameters;
-use crate::{FieldsIdsMap, GlobalFieldsIdsMap, Index, Result, UserError};
+use crate::{Error, FieldsIdsMap, GlobalFieldsIdsMap, Index, Result, UserError};
 
 mod document_deletion;
 mod document_operation;
@@ -37,7 +37,12 @@ pub trait DocumentChanges<'p> {
         self,
         fields_ids_map: &mut FieldsIdsMap,
         param: Self::Parameter,
-    ) -> Result<impl IndexedParallelIterator<Item = Result<DocumentChange>> + Clone + 'p>;
+    ) -> Result<
+        impl IndexedParallelIterator<
+                Item = std::result::Result<DocumentChange, Option<crate::Error>>,
+            > + Clone
+            + 'p,
+    >;
 }
 
 /// This is the main function of this crate.
@@ -53,7 +58,9 @@ pub fn index<PI>(
     document_changes: PI,
 ) -> Result<()>
 where
-    PI: IndexedParallelIterator<Item = Result<DocumentChange>> + Send + Clone,
+    PI: IndexedParallelIterator<Item = std::result::Result<DocumentChange, Option<Error>>>
+        + Send
+        + Clone,
 {
     let (merger_sender, writer_receiver) = merger_writer_channel(10_000);
     // This channel acts as a rendezvous point to ensure that we are one task ahead