From 31776fdc3ffcec5448024bf725c2e9f108b5a76e Mon Sep 17 00:00:00 2001
From: ad hoc <postma.marin@protonmail.com>
Date: Tue, 7 Jun 2022 12:24:06 +0200
Subject: [PATCH 1/2] add failing test

---
 milli/src/update/index_documents/mod.rs | 48 +++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/milli/src/update/index_documents/mod.rs b/milli/src/update/index_documents/mod.rs
index 117233611..5b6af12ae 100644
--- a/milli/src/update/index_documents/mod.rs
+++ b/milli/src/update/index_documents/mod.rs
@@ -1881,4 +1881,52 @@ mod tests {
 
         wtxn.commit().unwrap();
     }
+
+    #[test]
+    fn index_documents_in_multiple_transforms() {
+        let tmp = tempfile::tempdir().unwrap();
+        let mut options = EnvOpenOptions::new();
+        options.map_size(4096 * 100);
+        let index = Index::new(options, tmp).unwrap();
+        let mut wtxn = index.write_txn().unwrap();
+        let indexer_config = IndexerConfig::default();
+        let mut builder = IndexDocuments::new(
+            &mut wtxn,
+            &index,
+            &indexer_config,
+            IndexDocumentsConfig::default(),
+            |_| (),
+        )
+        .unwrap();
+
+        let doc1 = documents! {[{
+            "id": 228142,
+            "title": "asdsad",
+            "state": "automated",
+            "priority": "normal",
+            "public_uid": "37ccf021",
+            "project_id": 78207,
+            "branch_id_number": 0
+        }]};
+
+        let doc2 = documents! {[{
+            "id": 228143,
+            "title": "something",
+            "state": "automated",
+            "priority": "normal",
+            "public_uid": "39c6499b",
+            "project_id": 78207,
+            "branch_id_number": 0
+        }]};
+
+        builder.add_documents(doc1).unwrap();
+        builder.add_documents(doc2).unwrap();
+
+        builder.execute().unwrap();
+
+        let map = index.external_documents_ids(&wtxn).unwrap().to_hash_map();
+        let ids = map.values().collect::<HashSet<_>>();
+
+        assert_eq!(ids.len(), map.len());
+    }
 }

From d0aaa7ff0057204762006ee3263019d94e21abe1 Mon Sep 17 00:00:00 2001
From: Tamo <tamo@meilisearch.com>
Date: Tue, 7 Jun 2022 15:44:55 +0200
Subject: [PATCH 2/2] Fix wrong internal ids assignments

---
 milli/src/update/index_documents/transform.rs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/milli/src/update/index_documents/transform.rs b/milli/src/update/index_documents/transform.rs
index 9238212fd..08d450578 100644
--- a/milli/src/update/index_documents/transform.rs
+++ b/milli/src/update/index_documents/transform.rs
@@ -51,6 +51,7 @@ pub struct Transform<'a, 'i> {
     indexer_settings: &'a IndexerConfig,
     pub autogenerate_docids: bool,
     pub index_documents_method: IndexDocumentsMethod,
+    available_documents_ids: AvailableDocumentsIds,
 
     original_sorter: grenad::Sorter<MergeFn>,
     flattened_sorter: grenad::Sorter<MergeFn>,
@@ -128,12 +129,14 @@ impl<'a, 'i> Transform<'a, 'i> {
             indexer_settings.max_nb_chunks,
             indexer_settings.max_memory.map(|mem| mem / 2),
         );
+        let documents_ids = index.documents_ids(wtxn)?;
 
         Ok(Transform {
             index,
             fields_ids_map: index.fields_ids_map(wtxn)?,
             indexer_settings,
             autogenerate_docids,
+            available_documents_ids: AvailableDocumentsIds::from_documents_ids(&documents_ids),
             original_sorter,
             flattened_sorter,
             index_documents_method,
@@ -156,8 +159,6 @@ impl<'a, 'i> Transform<'a, 'i> {
     {
         let fields_index = reader.index();
         let external_documents_ids = self.index.external_documents_ids(wtxn)?;
-        let documents_ids = self.index.documents_ids(wtxn)?;
-        let mut available_documents_ids = AvailableDocumentsIds::from_documents_ids(&documents_ids);
 
         let mapping = create_fields_mapping(&mut self.fields_ids_map, fields_index)?;
 
@@ -261,7 +262,8 @@ impl<'a, 'i> Transform<'a, 'i> {
                             // if the document has never been encountered we give it a new docid
                             // and push this new docid to the external documents ids builder
                             Entry::Vacant(entry) => {
-                                let new_docid = available_documents_ids
+                                let new_docid = self
+                                    .available_documents_ids
                                     .next()
                                     .ok_or(UserError::DocumentLimitReached)?;
                                 entry.insert(new_docid as u64);