Give same interface to bulk and incremental facet indexing types

+ cargo fmt, oops, sorry for the bad history :(

milli/src/heed_codec/facet/mod.rs

@@ -3,17 +3,19 @@ mod field_doc_id_facet_string_codec;
 mod ordered_f64_codec;
 mod str_ref;
 
+use std::borrow::Cow;
+use std::convert::TryFrom;
+use std::marker::PhantomData;
+
+use heed::types::OwnedType;
+use heed::{BytesDecode, BytesEncode};
+use roaring::RoaringBitmap;
+
 pub use self::field_doc_id_facet_f64_codec::FieldDocIdFacetF64Codec;
 pub use self::field_doc_id_facet_string_codec::FieldDocIdFacetStringCodec;
 pub use self::ordered_f64_codec::OrderedF64Codec;
 pub use self::str_ref::StrRefCodec;
 use crate::{CboRoaringBitmapCodec, BEU16};
-use heed::types::OwnedType;
-use heed::{BytesDecode, BytesEncode};
-use roaring::RoaringBitmap;
-use std::borrow::Cow;
-use std::convert::TryFrom;
-use std::marker::PhantomData;
 
 pub type FieldIdCodec = OwnedType<BEU16>;
 

milli/src/index.rs

@@ -14,10 +14,10 @@ use time::OffsetDateTime;
 use crate::error::{InternalError, UserError};
 use crate::facet::FacetType;
 use crate::fields_ids_map::FieldsIdsMap;
-use crate::heed_codec::facet::OrderedF64Codec;
+use crate::heed_codec::facet::{
-use crate::heed_codec::facet::StrRefCodec;
+    FacetGroupKeyCodec, FacetGroupValueCodec, FieldDocIdFacetF64Codec, FieldDocIdFacetStringCodec,
-use crate::heed_codec::facet::{FacetGroupValueCodec, FacetGroupKeyCodec};
+    FieldIdCodec, OrderedF64Codec, StrRefCodec,
-use crate::heed_codec::facet::{FieldDocIdFacetF64Codec, FieldDocIdFacetStringCodec, FieldIdCodec};
+};
 use crate::{
     default_criteria, BEU32StrCodec, BoRoaringBitmapCodec, CboRoaringBitmapCodec, Criterion,
     DocumentId, ExternalDocumentsIds, FacetDistribution, FieldDistribution, FieldId,

milli/src/search/criteria/asc_desc.rs

@@ -7,7 +7,7 @@ use roaring::RoaringBitmap;
 
 use super::{Criterion, CriterionParameters, CriterionResult};
 use crate::facet::FacetType;
-use crate::heed_codec::facet::{FacetGroupKeyCodec, ByteSliceRef};
+use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec};
 use crate::search::criteria::{resolve_query_tree, CriteriaBuilder};
 use crate::search::facet::facet_sort_ascending::ascending_facet_sort;
 use crate::search::facet::facet_sort_descending::descending_facet_sort;

milli/src/search/distinct/facet_distinct.rs

@@ -6,8 +6,7 @@ use roaring::RoaringBitmap;
 
 use super::{Distinct, DocIter};
 use crate::error::InternalError;
-use crate::heed_codec::facet::FacetGroupKey;
+use crate::heed_codec::facet::{FacetGroupKey, *};
-use crate::heed_codec::facet::*;
 use crate::index::db_name;
 use crate::{DocumentId, FieldId, Index, Result};
 

milli/src/search/facet/facet_distribution.rs

@@ -8,10 +8,10 @@ use roaring::RoaringBitmap;
 
 use crate::error::UserError;
 use crate::facet::FacetType;
-use crate::heed_codec::facet::OrderedF64Codec;
+use crate::heed_codec::facet::{
-use crate::heed_codec::facet::StrRefCodec;
+    ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec, FieldDocIdFacetF64Codec,
-use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec};
+    FieldDocIdFacetStringCodec, OrderedF64Codec, StrRefCodec,
-use crate::heed_codec::facet::{FieldDocIdFacetF64Codec, FieldDocIdFacetStringCodec};
+};
 use crate::search::facet::facet_distribution_iter;
 use crate::{FieldId, Index, Result};
 

milli/src/search/facet/facet_distribution_iter.rs

@@ -112,17 +112,19 @@ where
 
 #[cfg(test)]
 mod tests {
+    use std::ops::ControlFlow;
+
+    use heed::BytesDecode;
+    use rand::{Rng, SeedableRng};
+    use roaring::RoaringBitmap;
+
     use super::iterate_over_facet_distribution;
     use crate::heed_codec::facet::OrderedF64Codec;
     use crate::milli_snap;
     use crate::search::facet::test::FacetIndex;
-    use heed::BytesDecode;
-    use rand::{Rng, SeedableRng};
-    use roaring::RoaringBitmap;
-    use std::ops::ControlFlow;
 
     fn get_simple_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
@@ -133,7 +135,7 @@ mod tests {
         index
     }
     fn get_random_looking_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

milli/src/search/facet/facet_range_search.rs

@@ -261,14 +261,13 @@ mod tests {
     use roaring::RoaringBitmap;
 
     use super::find_docids_of_facet_within_bounds;
-    use crate::heed_codec::facet::FacetGroupKeyCodec;
+    use crate::heed_codec::facet::{FacetGroupKeyCodec, OrderedF64Codec};
-    use crate::heed_codec::facet::OrderedF64Codec;
     use crate::milli_snap;
     use crate::search::facet::test::FacetIndex;
     use crate::snapshot_tests::display_bitmap;
 
     fn get_simple_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
@@ -279,7 +278,7 @@ mod tests {
         index
     }
     fn get_random_looking_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

milli/src/search/facet/facet_sort_ascending.rs

@@ -93,7 +93,7 @@ mod tests {
     use crate::snapshot_tests::display_bitmap;
 
     fn get_simple_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
@@ -104,7 +104,7 @@ mod tests {
         index
     }
     fn get_random_looking_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

milli/src/search/facet/facet_sort_descending.rs

@@ -119,15 +119,14 @@ mod tests {
     use rand::{Rng, SeedableRng};
     use roaring::RoaringBitmap;
 
-    use crate::heed_codec::facet::OrderedF64Codec;
+    use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, OrderedF64Codec};
-    use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec};
     use crate::milli_snap;
     use crate::search::facet::facet_sort_descending::descending_facet_sort;
     use crate::search::facet::test::FacetIndex;
     use crate::snapshot_tests::display_bitmap;
 
     fn get_simple_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
@@ -138,7 +137,7 @@ mod tests {
         index
     }
     fn get_random_looking_index() -> FacetIndex<OrderedF64Codec> {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

milli/src/search/facet/filter.rs

@@ -9,8 +9,9 @@ use roaring::RoaringBitmap;
 
 use super::facet_range_search;
 use crate::error::{Error, UserError};
-use crate::heed_codec::facet::OrderedF64Codec;
+use crate::heed_codec::facet::{
-use crate::heed_codec::facet::{FacetGroupKey, FacetGroupKeyCodec, FacetGroupValueCodec};
+    FacetGroupKey, FacetGroupKeyCodec, FacetGroupValueCodec, OrderedF64Codec,
+};
 use crate::{distance_between_two_points, lat_lng_to_xyz, FieldId, Index, Result};
 
 /// The maximum number of filters the filter AST can process.

milli/src/search/facet/mod.rs

@@ -3,7 +3,7 @@ use heed::{BytesDecode, RoTxn};
 
 pub use self::facet_distribution::{FacetDistribution, DEFAULT_VALUES_PER_FACET};
 pub use self::filter::Filter;
-use crate::heed_codec::facet::{FacetGroupValueCodec, FacetGroupKeyCodec, ByteSliceRef};
+use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec};
 
 mod facet_distribution;
 mod facet_distribution_iter;
@@ -27,8 +27,8 @@ where
         db.as_polymorph().prefix_iter::<_, ByteSlice, ByteSlice>(txn, level0prefix.as_slice())?;
     if let Some(first) = level0_iter_forward.next() {
         let (first_key, _) = first?;
-        let first_key =
+        let first_key = FacetGroupKeyCodec::<BoundCodec>::bytes_decode(first_key)
-            FacetGroupKeyCodec::<BoundCodec>::bytes_decode(first_key).ok_or(heed::Error::Encoding)?;
+            .ok_or(heed::Error::Encoding)?;
         Ok(Some(first_key.left_bound))
     } else {
         Ok(None)
@@ -50,8 +50,8 @@ where
         .rev_prefix_iter::<_, ByteSlice, ByteSlice>(txn, level0prefix.as_slice())?;
     if let Some(last) = level0_iter_backward.next() {
         let (last_key, _) = last?;
-        let last_key =
+        let last_key = FacetGroupKeyCodec::<BoundCodec>::bytes_decode(last_key)
-            FacetGroupKeyCodec::<BoundCodec>::bytes_decode(last_key).ok_or(heed::Error::Encoding)?;
+            .ok_or(heed::Error::Encoding)?;
         Ok(Some(last_key.left_bound))
     } else {
         Ok(None)
@@ -85,11 +85,12 @@ pub mod test {
     use roaring::RoaringBitmap;
 
     use crate::heed_codec::facet::{
-        FacetGroupValue, FacetGroupValueCodec, FacetGroupKey, FacetGroupKeyCodec, ByteSliceRef,
+        ByteSliceRef, FacetGroupKey, FacetGroupKeyCodec, FacetGroupValue, FacetGroupValueCodec,
     };
     use crate::snapshot_tests::display_bitmap;
-    use crate::update::FacetsUpdateIncremental;
+    use crate::update::FacetsUpdateIncrementalInner;
 
+    // A dummy index that only contains the facet database, used for testing
     pub struct FacetIndex<BoundCodec>
     where
         for<'a> BoundCodec:
@@ -100,10 +101,12 @@ pub mod test {
         _phantom: PhantomData<BoundCodec>,
     }
 
+    // The faecet database and its settings
     pub struct Database {
         pub content: heed::Database<FacetGroupKeyCodec<ByteSliceRef>, FacetGroupValueCodec>,
-        pub group_size: usize,
+        pub group_size: u8,
-        pub max_group_size: usize,
+        pub min_level_size: u8,
+        pub max_group_size: u8,
         _tempdir: Rc<tempfile::TempDir>,
     }
 
@@ -117,9 +120,12 @@ pub mod test {
             tempdir: Rc<tempfile::TempDir>,
             group_size: u8,
             max_group_size: u8,
+            min_level_size: u8,
         ) -> FacetIndex<BoundCodec> {
-            let group_size = std::cmp::min(127, std::cmp::max(group_size, 2)) as usize;
+            let group_size = std::cmp::min(127, std::cmp::max(group_size, 2)); // 2 <= x <= 127
-            let max_group_size = std::cmp::max(group_size * 2, max_group_size as usize);
+            let max_group_size = std::cmp::min(127, std::cmp::max(group_size * 2, max_group_size)); // 2*group_size <= x <= 127
+            let min_level_size = std::cmp::max(1, min_level_size); // 1 <= x <= inf
+
             let mut options = heed::EnvOpenOptions::new();
             let options = options.map_size(4096 * 4 * 10 * 100);
             unsafe {
@@ -129,14 +135,25 @@ pub mod test {
             let content = env.open_database(None).unwrap().unwrap();
 
             FacetIndex {
-                db: Database { content, group_size, max_group_size, _tempdir: tempdir },
+                db: Database {
+                    content,
+                    group_size,
+                    max_group_size,
+                    min_level_size,
+                    _tempdir: tempdir,
+                },
                 env,
                 _phantom: PhantomData,
             }
         }
-        pub fn new(group_size: u8, max_group_size: u8) -> FacetIndex<BoundCodec> {
+        pub fn new(
-            let group_size = std::cmp::min(127, std::cmp::max(group_size, 2)) as usize;
+            group_size: u8,
-            let max_group_size = std::cmp::max(group_size * 2, max_group_size as usize);
+            max_group_size: u8,
+            min_level_size: u8,
+        ) -> FacetIndex<BoundCodec> {
+            let group_size = std::cmp::min(127, std::cmp::max(group_size, 2)); // 2 <= x <= 127
+            let max_group_size = std::cmp::min(127, std::cmp::max(group_size * 2, max_group_size)); // 2*group_size <= x <= 127
+            let min_level_size = std::cmp::max(1, min_level_size); // 1 <= x <= inf
             let mut options = heed::EnvOpenOptions::new();
             let options = options.map_size(4096 * 4 * 100);
             let tempdir = tempfile::TempDir::new().unwrap();
@@ -144,7 +161,13 @@ pub mod test {
             let content = env.create_database(None).unwrap();
 
             FacetIndex {
-                db: Database { content, group_size, max_group_size, _tempdir: Rc::new(tempdir) },
+                db: Database {
+                    content,
+                    group_size,
+                    max_group_size,
+                    min_level_size,
+                    _tempdir: Rc::new(tempdir),
+                },
                 env,
                 _phantom: PhantomData,
             }
@@ -156,7 +179,7 @@ pub mod test {
             key: &'a <BoundCodec as BytesEncode<'a>>::EItem,
             docids: &RoaringBitmap,
         ) {
-            let update = FacetsUpdateIncremental::new(self.db.content);
+            let update = FacetsUpdateIncrementalInner::new(self.db.content);
             let key_bytes = BoundCodec::bytes_encode(&key).unwrap();
             update.insert(rwtxn, field_id, &key_bytes, docids).unwrap();
         }
@@ -167,7 +190,7 @@ pub mod test {
             key: &'a <BoundCodec as BytesEncode<'a>>::EItem,
             value: u32,
         ) {
-            let update = FacetsUpdateIncremental::new(self.db.content);
+            let update = FacetsUpdateIncrementalInner::new(self.db.content);
             let key_bytes = BoundCodec::bytes_encode(&key).unwrap();
             update.delete(rwtxn, field_id, &key_bytes, value).unwrap();
         }

milli/src/snapshot_tests.rs

@@ -5,7 +5,7 @@ use std::path::Path;
 use roaring::RoaringBitmap;
 
 use crate::facet::FacetType;
-use crate::heed_codec::facet::{FacetGroupValue, FacetGroupKey};
+use crate::heed_codec::facet::{FacetGroupKey, FacetGroupValue};
 use crate::{make_db_snap_from_iter, ExternalDocumentsIds, Index};
 
 #[track_caller]

milli/src/update/clear_documents.rs

@@ -1,7 +1,8 @@
 use roaring::RoaringBitmap;
 use time::OffsetDateTime;
 
-use crate::{facet::FacetType, ExternalDocumentsIds, FieldDistribution, Index, Result};
+use crate::facet::FacetType;
+use crate::{ExternalDocumentsIds, FieldDistribution, Index, Result};
 
 pub struct ClearDocuments<'t, 'u, 'i> {
     wtxn: &'t mut heed::RwTxn<'i, 'u>,

milli/src/update/delete_documents.rs

@@ -11,7 +11,7 @@ use time::OffsetDateTime;
 use super::{ClearDocuments, FacetsUpdateBulk};
 use crate::error::{InternalError, UserError};
 use crate::facet::FacetType;
-use crate::heed_codec::facet::{FacetGroupValueCodec, FacetGroupKeyCodec, ByteSliceRef};
+use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec};
 use crate::heed_codec::CboRoaringBitmapCodec;
 use crate::index::{db_name, main_key};
 use crate::{

milli/src/update/facet/bulk.rs

@@ -1,18 +1,20 @@
+use std::borrow::Cow;
+use std::cmp;
+use std::fs::File;
+
+use grenad::CompressionType;
+use heed::types::ByteSlice;
+use heed::{BytesEncode, Error, RoTxn, RwTxn};
+use log::debug;
+use roaring::RoaringBitmap;
+use time::OffsetDateTime;
+
 use crate::facet::FacetType;
 use crate::heed_codec::facet::{
     ByteSliceRef, FacetGroupKey, FacetGroupKeyCodec, FacetGroupValue, FacetGroupValueCodec,
 };
 use crate::update::index_documents::{create_writer, writer_into_reader};
 use crate::{CboRoaringBitmapCodec, FieldId, Index, Result};
-use grenad::CompressionType;
-use heed::types::ByteSlice;
-use heed::{BytesEncode, Error, RoTxn, RwTxn};
-use log::debug;
-use roaring::RoaringBitmap;
-use std::borrow::Cow;
-use std::cmp;
-use std::fs::File;
-use time::OffsetDateTime;
 
 pub struct FacetsUpdateBulk<'i> {
     index: &'i Index,
@@ -367,9 +369,7 @@ mod tests {
                     documents.push(serde_json::json!({ "facet2": i }).as_object().unwrap().clone());
                 }
                 let documents = documents_batch_reader_from_objects(documents);
-                dbg!();
                 index.add_documents(documents).unwrap();
-                dbg!();
                 db_snap!(index, facet_id_f64_docids, name);
             };
 
@@ -421,4 +421,100 @@ mod tests {
         test("default", None, None);
         test("tiny_groups_tiny_levels", NonZeroUsize::new(1), NonZeroUsize::new(1));
     }
+
+    #[test]
+    fn test_facets_number_incremental_update() {
+        let test =
+            |name: &str, group_size: Option<NonZeroUsize>, min_level_size: Option<NonZeroUsize>| {
+                let mut index = TempIndex::new_with_map_size(4096 * 1000 * 10); // 40MB
+                index.index_documents_config.autogenerate_docids = true;
+                index.index_documents_config.facet_level_group_size = group_size;
+                index.index_documents_config.facet_min_level_size = min_level_size;
+
+                index
+                    .update_settings(|settings| {
+                        settings.set_filterable_fields(
+                            IntoIterator::into_iter(["facet".to_owned(), "facet2".to_owned()])
+                                .collect(),
+                        );
+                    })
+                    .unwrap();
+
+                let mut documents = vec![];
+                for i in 0..1000 {
+                    documents.push(serde_json::json!({ "facet": i }).as_object().unwrap().clone());
+                }
+                for i in 0..100 {
+                    documents.push(serde_json::json!({ "facet2": i }).as_object().unwrap().clone());
+                }
+                let documents_batch = documents_batch_reader_from_objects(documents.clone());
+
+                index.add_documents(documents_batch).unwrap();
+
+                let mut documents = vec![];
+                for i in 1000..1010 {
+                    documents.push(serde_json::json!({ "facet": i }).as_object().unwrap().clone());
+                }
+                for i in 100..110 {
+                    documents.push(serde_json::json!({ "facet2": i }).as_object().unwrap().clone());
+                }
+                let documents_batch = documents_batch_reader_from_objects(documents.clone());
+
+                index.add_documents(documents_batch).unwrap();
+
+                db_snap!(index, facet_id_f64_docids, name);
+            };
+
+        test("default", None, None);
+        test("tiny_groups_tiny_levels", NonZeroUsize::new(1), NonZeroUsize::new(1));
+    }
+
+    #[test]
+    fn test_facets_number_delete_facet_id_then_bulk_update() {
+        let test =
+            |name: &str, group_size: Option<NonZeroUsize>, min_level_size: Option<NonZeroUsize>| {
+                let mut index = TempIndex::new_with_map_size(4096 * 1000 * 10); // 40MB
+                index.index_documents_config.autogenerate_docids = true;
+                index.index_documents_config.facet_level_group_size = group_size;
+                index.index_documents_config.facet_min_level_size = min_level_size;
+
+                index
+                    .update_settings(|settings| {
+                        settings.set_filterable_fields(
+                            IntoIterator::into_iter(["facet".to_owned(), "facet2".to_owned()])
+                                .collect(),
+                        );
+                    })
+                    .unwrap();
+
+                let mut documents = vec![];
+                for i in 0..1000 {
+                    documents.push(serde_json::json!({ "facet": i }).as_object().unwrap().clone());
+                }
+                for i in 0..100 {
+                    documents.push(serde_json::json!({ "facet2": i }).as_object().unwrap().clone());
+                }
+                let documents_batch = documents_batch_reader_from_objects(documents.clone());
+
+                index.add_documents(documents_batch).unwrap();
+
+                // 1100 facets -> how long is the DB?
+
+                let mut documents = vec![];
+                for i in 1000..1010 {
+                    documents.push(serde_json::json!({ "facet": i }).as_object().unwrap().clone());
+                }
+                for i in 100..110 {
+                    documents.push(serde_json::json!({ "facet2": i }).as_object().unwrap().clone());
+                }
+                let documents_batch = documents_batch_reader_from_objects(documents.clone());
+
+                index.add_documents(documents_batch).unwrap();
+
+                db_snap!(index, facet_id_f64_docids, name);
+            };
+
+        test("default", None, None);
+        test("tiny_groups_tiny_levels", NonZeroUsize::new(1), NonZeroUsize::new(1));
+    }
 }

milli/src/update/facet/incremental.rs

@@ -1,12 +1,16 @@
+use std::collections::HashMap;
+use std::fs::File;
+
 use heed::types::ByteSlice;
 use heed::{BytesDecode, Error, RoTxn, RwTxn};
 use roaring::RoaringBitmap;
 
+use crate::facet::FacetType;
 use crate::heed_codec::facet::{
     ByteSliceRef, FacetGroupKey, FacetGroupKeyCodec, FacetGroupValue, FacetGroupValueCodec,
 };
 use crate::search::facet::get_highest_level;
-use crate::Result;
+use crate::{CboRoaringBitmapCodec, FieldId, Index, Result};
 
 enum InsertionResult {
     InPlace,
@@ -18,30 +22,79 @@ enum DeletionResult {
     Remove { prev: Option<Vec<u8>>, next: Option<Vec<u8>> },
 }
 
-pub struct FacetsUpdateIncremental {
+pub struct FacetsUpdateIncremental<'i> {
+    index: &'i Index,
+    inner: FacetsUpdateIncrementalInner,
+    facet_type: FacetType,
+    new_data: grenad::Reader<File>,
+}
+
+impl<'i> FacetsUpdateIncremental<'i> {
+    pub fn new(index: &'i Index, facet_type: FacetType, new_data: grenad::Reader<File>) -> Self {
+        FacetsUpdateIncremental {
+            index,
+            inner: FacetsUpdateIncrementalInner {
+                db: match facet_type {
+                    FacetType::String => index
+                        .facet_id_string_docids
+                        .remap_key_type::<FacetGroupKeyCodec<ByteSliceRef>>(),
+                    FacetType::Number => index
+                        .facet_id_f64_docids
+                        .remap_key_type::<FacetGroupKeyCodec<ByteSliceRef>>(),
+                },
+                group_size: 4,
+                max_group_size: 8,
+                min_level_size: 5,
+            },
+            facet_type,
+            new_data,
+        }
+    }
+    pub fn group_size(mut self, size: u8) -> Self {
+        self.inner.group_size = size;
+        self
+    }
+    pub fn min_level_size(mut self, size: u8) -> Self {
+        self.inner.min_level_size = size;
+        self
+    }
+    pub fn max_group_size(mut self, size: u8) -> Self {
+        self.inner.max_group_size = size;
+        self
+    }
+    pub fn execute(self, wtxn: &'i mut RwTxn) -> crate::Result<()> {
+        let mut new_faceted_docids = HashMap::<FieldId, RoaringBitmap>::default();
+
+        let mut cursor = self.new_data.into_cursor()?;
+        while let Some((key, value)) = cursor.move_on_next()? {
+            let key = FacetGroupKeyCodec::<ByteSliceRef>::bytes_decode(key)
+                .ok_or(heed::Error::Encoding)?;
+            let docids = CboRoaringBitmapCodec::bytes_decode(value).ok_or(heed::Error::Encoding)?;
+            self.inner.insert(wtxn, key.field_id, key.left_bound, &docids)?;
+            *new_faceted_docids.entry(key.field_id).or_default() |= docids;
+        }
+
+        for (field_id, new_docids) in new_faceted_docids {
+            let mut docids = self.index.faceted_documents_ids(wtxn, field_id, self.facet_type)?;
+            docids |= new_docids;
+            self.index.put_faceted_documents_ids(wtxn, field_id, self.facet_type, &docids)?;
+        }
+        Ok(())
+    }
+}
+
+pub struct FacetsUpdateIncrementalInner {
     db: heed::Database<FacetGroupKeyCodec<ByteSliceRef>, FacetGroupValueCodec>,
     group_size: u8,
     min_level_size: u8,
     max_group_size: u8,
 }
-impl FacetsUpdateIncremental {
+impl FacetsUpdateIncrementalInner {
     pub fn new(db: heed::Database<FacetGroupKeyCodec<ByteSliceRef>, FacetGroupValueCodec>) -> Self {
         Self { db, group_size: 4, min_level_size: 5, max_group_size: 8 }
     }
-    pub fn group_size(mut self, size: u8) -> Self {
-        self.group_size = size;
-        self
-    }
-    pub fn min_level_size(mut self, size: u8) -> Self {
-        self.min_level_size = size;
-        self
-    }
-    pub fn max_group_size(mut self, size: u8) -> Self {
-        self.max_group_size = size;
-        self
-    }
 }
-impl FacetsUpdateIncremental {
+impl FacetsUpdateIncrementalInner {
     fn find_insertion_key_value(
         &self,
         field_id: u16,
@@ -481,9 +534,9 @@ mod tests {
     use rand::{Rng, SeedableRng};
     use roaring::RoaringBitmap;
 
-    use crate::heed_codec::facet::OrderedF64Codec;
+    use crate::heed_codec::facet::{
-    use crate::heed_codec::facet::StrRefCodec;
+        ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec, OrderedF64Codec, StrRefCodec,
-    use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec};
+    };
     use crate::milli_snap;
     use crate::search::facet::get_highest_level;
     use crate::search::facet::test::FacetIndex;
@@ -534,7 +587,7 @@ mod tests {
                     FacetGroupKeyCodec::<ByteSliceRef>::bytes_decode(&key_bytes).unwrap()
                 };
 
-                assert!(value.size > 0 && (value.size as usize) < db.max_group_size);
+                assert!(value.size > 0 && value.size < db.max_group_size);
 
                 let mut actual_size = 0;
                 let mut values_below = RoaringBitmap::new();
@@ -553,7 +606,7 @@ mod tests {
     }
     #[test]
     fn append() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
             bitmap.insert(i as u32);
@@ -566,7 +619,7 @@ mod tests {
     }
     #[test]
     fn many_field_ids_append() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         for i in 0..256u16 {
             let mut bitmap = RoaringBitmap::new();
             bitmap.insert(i as u32);
@@ -595,7 +648,7 @@ mod tests {
     }
     #[test]
     fn many_field_ids_prepend() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         for i in (0..256).into_iter().rev() {
             let mut bitmap = RoaringBitmap::new();
             bitmap.insert(i as u32);
@@ -625,7 +678,7 @@ mod tests {
 
     #[test]
     fn prepend() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         for i in (0..256).into_iter().rev() {
@@ -640,7 +693,7 @@ mod tests {
 
     #[test]
     fn shuffled() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut txn = index.env.write_txn().unwrap();
 
         let mut keys = (0..256).into_iter().collect::<Vec<_>>();
@@ -659,7 +712,7 @@ mod tests {
 
     #[test]
     fn merge_values() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
 
         let mut keys = (0..256).into_iter().collect::<Vec<_>>();
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);
@@ -680,7 +733,7 @@ mod tests {
 
     #[test]
     fn delete_from_end() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         for i in 0..256 {
             let mut bitmap = RoaringBitmap::new();
             bitmap.insert(i);
@@ -745,7 +798,7 @@ mod tests {
 
     #[test]
     fn delete_from_start() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
 
         for i in 0..256 {
             let mut bitmap = RoaringBitmap::new();
@@ -783,7 +836,7 @@ mod tests {
 
     #[test]
     fn delete_shuffled() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
 
         for i in 0..256 {
             let mut bitmap = RoaringBitmap::new();
@@ -829,7 +882,7 @@ mod tests {
 
     #[test]
     fn in_place_level0_insert() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
         let mut keys = (0..16).into_iter().collect::<Vec<_>>();
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);
         keys.shuffle(&mut rng);
@@ -849,7 +902,7 @@ mod tests {
 
     #[test]
     fn in_place_level0_delete() {
-        let index = FacetIndex::<OrderedF64Codec>::new(4, 8);
+        let index = FacetIndex::<OrderedF64Codec>::new(4, 8, 5);
 
         let mut keys = (0..64).into_iter().collect::<Vec<_>>();
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);
@@ -879,7 +932,7 @@ mod tests {
 
     #[test]
     fn shuffle_merge_string_and_delete() {
-        let index = FacetIndex::<StrRefCodec>::new(4, 8);
+        let index = FacetIndex::<StrRefCodec>::new(4, 8, 5);
 
         let mut keys = (1000..1064).into_iter().collect::<Vec<_>>();
         let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

milli/src/update/facet/mod.rs

@@ -1,12 +1,9 @@
-use super::{FacetsUpdateBulk, FacetsUpdateIncremental};
+use self::incremental::FacetsUpdateIncremental;
-use crate::{
+use super::FacetsUpdateBulk;
-    facet::FacetType,
+use crate::facet::FacetType;
-    heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec},
+use crate::heed_codec::facet::{ByteSliceRef, FacetGroupKeyCodec, FacetGroupValueCodec};
-    CboRoaringBitmapCodec, FieldId, Index, Result,
+use crate::{Index, Result};
-};
+use std::fs::File;
-use heed::BytesDecode;
-use roaring::RoaringBitmap;
-use std::{collections::HashMap, fs::File};
 
 pub mod bulk;
 pub mod incremental;
@@ -14,11 +11,13 @@ pub mod incremental;
 pub struct FacetsUpdate<'i> {
     index: &'i Index,
     database: heed::Database<FacetGroupKeyCodec<ByteSliceRef>, FacetGroupValueCodec>,
+    facet_type: FacetType,
+    new_data: grenad::Reader<File>,
+    // Options:
+    // there's no way to change these for now
     level_group_size: u8,
     max_level_group_size: u8,
     min_level_size: u8,
-    facet_type: FacetType,
-    new_data: grenad::Reader<File>,
 }
 impl<'i> FacetsUpdate<'i> {
     pub fn new(index: &'i Index, facet_type: FacetType, new_data: grenad::Reader<File>) -> Self {
@@ -42,36 +41,37 @@ impl<'i> FacetsUpdate<'i> {
     }
 
     pub fn execute(self, wtxn: &mut heed::RwTxn) -> Result<()> {
+        if self.new_data.is_empty() {
+            return Ok(());
+        }
         // here, come up with a better condition!
-        if self.database.is_empty(wtxn)? {
+        // ideally we'd choose which method to use for each field id individually
+        // but I dont' think it's worth the effort yet
+        // As a first requirement, we ask that the length of the new data is less
+        // than a 1/50th of the length of the database in order to use the incremental
+        // method.
+        if self.new_data.len() >= (self.database.len(wtxn)? as u64 / 50) {
             let bulk_update = FacetsUpdateBulk::new(self.index, self.facet_type, self.new_data)
                 .level_group_size(self.level_group_size)
                 .min_level_size(self.min_level_size);
             bulk_update.execute(wtxn)?;
         } else {
-            let indexer = FacetsUpdateIncremental::new(self.database)
+            let incremental_update =
-                .max_group_size(self.max_level_group_size)
+                FacetsUpdateIncremental::new(self.index, self.facet_type, self.new_data)
-                .min_level_size(self.min_level_size);
+                    .group_size(self.level_group_size)
-
+                    .max_group_size(self.max_level_group_size)
-            let mut new_faceted_docids = HashMap::<FieldId, RoaringBitmap>::default();
+                    .min_level_size(self.min_level_size);
-
+            incremental_update.execute(wtxn)?;
-            let mut cursor = self.new_data.into_cursor()?;
-            while let Some((key, value)) = cursor.move_on_next()? {
-                let key = FacetGroupKeyCodec::<ByteSliceRef>::bytes_decode(key)
-                    .ok_or(heed::Error::Encoding)?;
-                let docids =
-                    CboRoaringBitmapCodec::bytes_decode(value).ok_or(heed::Error::Encoding)?;
-                indexer.insert(wtxn, key.field_id, key.left_bound, &docids)?;
-                *new_faceted_docids.entry(key.field_id).or_default() |= docids;
-            }
-
-            for (field_id, new_docids) in new_faceted_docids {
-                let mut docids =
-                    self.index.faceted_documents_ids(wtxn, field_id, self.facet_type)?;
-                docids |= new_docids;
-                self.index.put_faceted_documents_ids(wtxn, field_id, self.facet_type, &docids)?;
-            }
         }
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    // here I want to create a benchmark
+    // to find out at which point it is faster to do it incrementally
+
+    #[test]
+    fn update() {}
+}

milli/src/update/facet/snapshots/bulk.rs/test_facets_number_update/default/facet_id_f64_docids.hash.snap

@@ -0,0 +1,4 @@
+---
+source: milli/src/update/facet/bulk.rs
+---
+9e9175e0a56db39f0dc04fb8f15c28fe

milli/src/update/facet/snapshots/bulk.rs/test_facets_number_update/tiny_groups_tiny_levels/facet_id_f64_docids.hash.snap

@@ -0,0 +1,4 @@
+---
+source: milli/src/update/facet/bulk.rs
+---
+9e9175e0a56db39f0dc04fb8f15c28fe

milli/src/update/facet/snapshots/bulk.rs/test_facets_string_update/default/facet_id_string_docids.hash.snap

@@ -0,0 +1,4 @@
+---
+source: milli/src/update/facet/bulk.rs
+---
+b494fb6565707ce401f6d6ac03f46b93

milli/src/update/facet/snapshots/bulk.rs/test_facets_string_update/tiny_groups_tiny_levels/facet_id_string_docids.hash.snap

@@ -0,0 +1,4 @@
+---
+source: milli/src/update/facet/bulk.rs
+---
+b494fb6565707ce401f6d6ac03f46b93

milli/src/update/index_documents/extract/extract_facet_number_docids.rs

@@ -6,9 +6,9 @@ use heed::{BytesDecode, BytesEncode};
 use super::helpers::{
     create_sorter, merge_cbo_roaring_bitmaps, sorter_into_reader, GrenadParameters,
 };
-use crate::heed_codec::facet::FieldDocIdFacetF64Codec;
+use crate::heed_codec::facet::{
-use crate::heed_codec::facet::OrderedF64Codec;
+    FacetGroupKey, FacetGroupKeyCodec, FieldDocIdFacetF64Codec, OrderedF64Codec,
-use crate::heed_codec::facet::{FacetGroupKey, FacetGroupKeyCodec};
+};
 use crate::Result;
 
 /// Extracts the facet number and the documents ids where this facet number appear.

milli/src/update/index_documents/extract/extract_facet_string_docids.rs

@@ -4,8 +4,7 @@ use std::io;
 use heed::BytesEncode;
 
 use super::helpers::{create_sorter, sorter_into_reader, try_split_array_at, GrenadParameters};
-use crate::heed_codec::facet::StrRefCodec;
+use crate::heed_codec::facet::{FacetGroupKey, FacetGroupKeyCodec, StrRefCodec};
-use crate::heed_codec::facet::{FacetGroupKey, FacetGroupKeyCodec};
 use crate::update::index_documents::merge_cbo_roaring_bitmaps;
 use crate::{FieldId, Result};
 

milli/src/update/index_documents/helpers/grenad_helpers.rs

@@ -3,7 +3,7 @@ use std::fs::File;
 use std::io::{self, Seek, SeekFrom};
 use std::time::Instant;
 
-use grenad::{CompressionType, Reader, Sorter};
+use grenad::{CompressionType, Sorter};
 use heed::types::ByteSlice;
 use log::debug;
 
@@ -208,36 +208,6 @@ pub fn grenad_obkv_into_chunks<R: io::Read + io::Seek>(
     Ok(std::iter::from_fn(move || transposer().transpose()))
 }
 
-pub fn write_into_lmdb_database(
-    wtxn: &mut heed::RwTxn,
-    database: heed::PolyDatabase,
-    reader: Reader<File>,
-    merge: MergeFn,
-) -> Result<()> {
-    debug!("Writing MTBL stores...");
-    let before = Instant::now();
-
-    let mut cursor = reader.into_cursor()?;
-    while let Some((k, v)) = cursor.move_on_next()? {
-        let mut iter = database.prefix_iter_mut::<_, ByteSlice, ByteSlice>(wtxn, k)?;
-        match iter.next().transpose()? {
-            Some((key, old_val)) if key == k => {
-                let vals = &[Cow::Borrowed(old_val), Cow::Borrowed(v)][..];
-                let val = merge(k, vals)?;
-                // safety: we don't keep references from inside the LMDB database.
-                unsafe { iter.put_current(k, &val)? };
-            }
-            _ => {
-                drop(iter);
-                database.put::<_, ByteSlice, ByteSlice>(wtxn, k, v)?;
-            }
-        }
-    }
-
-    debug!("MTBL stores merged in {:.02?}!", before.elapsed());
-    Ok(())
-}
-
 pub fn sorter_into_lmdb_database(
     wtxn: &mut heed::RwTxn,
     database: heed::PolyDatabase,

milli/src/update/index_documents/helpers/mod.rs

@@ -9,8 +9,8 @@ pub use clonable_mmap::{ClonableMmap, CursorClonableMmap};
 use fst::{IntoStreamer, Streamer};
 pub use grenad_helpers::{
     as_cloneable_grenad, create_sorter, create_writer, grenad_obkv_into_chunks,
-    merge_ignore_values, sorter_into_lmdb_database, sorter_into_reader, write_into_lmdb_database,
+    merge_ignore_values, sorter_into_lmdb_database, sorter_into_reader, writer_into_reader,
-    writer_into_reader, GrenadParameters, MergeableReader,
+    GrenadParameters, MergeableReader,
 };
 pub use merge_functions::{
     concat_u32s_array, keep_first, keep_latest_obkv, merge_cbo_roaring_bitmaps, merge_obkvs,

milli/src/update/index_documents/mod.rs

@@ -27,8 +27,7 @@ pub use self::enrich::{
 pub use self::helpers::{
     as_cloneable_grenad, create_sorter, create_writer, fst_stream_into_hashset,
     fst_stream_into_vec, merge_cbo_roaring_bitmaps, merge_roaring_bitmaps,
-    sorter_into_lmdb_database, valid_lmdb_key, write_into_lmdb_database, writer_into_reader,
+    sorter_into_lmdb_database, valid_lmdb_key, writer_into_reader, ClonableMmap, MergeFn,
-    ClonableMmap, MergeFn,
 };
 use self::helpers::{grenad_obkv_into_chunks, GrenadParameters};
 pub use self::transform::{Transform, TransformOutput};

milli/src/update/mod.rs

@@ -2,7 +2,7 @@ pub use self::available_documents_ids::AvailableDocumentsIds;
 pub use self::clear_documents::ClearDocuments;
 pub use self::delete_documents::{DeleteDocuments, DocumentDeletionResult};
 pub use self::facet::bulk::FacetsUpdateBulk;
-pub use self::facet::incremental::FacetsUpdateIncremental;
+pub use self::facet::incremental::FacetsUpdateIncrementalInner;
 pub use self::index_documents::{
     DocumentAdditionResult, DocumentId, IndexDocuments, IndexDocumentsConfig, IndexDocumentsMethod,
 };