Support diff indexing on extract_docid_word_positions

milli/src/update/del_add.rs

@@ -58,3 +58,43 @@ pub fn into_del_add_obkv<K: obkv::Key + PartialOrd>(
 
     writer.finish()
 }
+
+/// Creates a Kv<K, Kv<DelAdd, value>> from two Kv<K, value>
+///
+/// putting each deletion obkv's keys under an DelAdd::Deletion
+/// and putting each addition obkv's keys under an DelAdd::Addition
+pub fn del_add_from_two_obkvs<K: obkv::Key + PartialOrd + Ord>(
+    deletion: obkv::KvReader<K>,
+    addition: obkv::KvReader<K>,
+    buffer: &mut Vec<u8>,
+) -> Result<(), std::io::Error> {
+    use itertools::merge_join_by;
+    use itertools::EitherOrBoth::{Both, Left, Right};
+
+    let mut writer = obkv::KvWriter::new(buffer);
+    let mut value_buffer = Vec::new();
+
+    for eob in merge_join_by(deletion.iter(), addition.iter(), |(b, _), (u, _)| b.cmp(u)) {
+        value_buffer.clear();
+        match eob {
+            Left((k, v)) => {
+                let mut value_writer = KvWriterDelAdd::new(&mut value_buffer);
+                value_writer.insert(DelAdd::Deletion, v).unwrap();
+                writer.insert(k, value_writer.into_inner()?).unwrap();
+            }
+            Right((k, v)) => {
+                let mut value_writer = KvWriterDelAdd::new(&mut value_buffer);
+                value_writer.insert(DelAdd::Addition, v).unwrap();
+                writer.insert(k, value_writer.into_inner()?).unwrap();
+            }
+            Both((k, deletion), (_, addition)) => {
+                let mut value_writer = KvWriterDelAdd::new(&mut value_buffer);
+                value_writer.insert(DelAdd::Deletion, deletion).unwrap();
+                value_writer.insert(DelAdd::Addition, addition).unwrap();
+                writer.insert(k, value_writer.into_inner()?).unwrap();
+            }
+        }
+    }
+
+    writer.finish()
+}

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

@@ -11,7 +11,7 @@ use serde_json::Value;
 
 use super::helpers::{create_sorter, keep_latest_obkv, sorter_into_reader, GrenadParameters};
 use crate::error::{InternalError, SerializationError};
-use crate::update::index_documents::MergeFn;
+use crate::update::del_add::{del_add_from_two_obkvs, DelAdd, KvReaderDelAdd};
 use crate::{FieldId, Result, MAX_POSITION_PER_ATTRIBUTE, MAX_WORD_LENGTH};
 
 pub type ScriptLanguageDocidsMap = HashMap<(Script, Language), RoaringBitmap>;
@@ -30,15 +30,21 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
     allowed_separators: Option<&[&str]>,
     dictionary: Option<&[&str]>,
     max_positions_per_attributes: Option<u32>,
-) -> Result<(RoaringBitmap, grenad::Reader<BufReader<File>>, ScriptLanguageDocidsMap)> {
+) -> Result<(
+    RoaringBitmap,
+    grenad::Reader<BufReader<File>>,
+    (ScriptLanguageDocidsMap, ScriptLanguageDocidsMap),
+)> {
     puffin::profile_function!();
 
     let max_positions_per_attributes = max_positions_per_attributes
         .map_or(MAX_POSITION_PER_ATTRIBUTE, |max| max.min(MAX_POSITION_PER_ATTRIBUTE));
     let max_memory = indexer.max_memory_by_thread();
 
+    // initialize destination values.
     let mut documents_ids = RoaringBitmap::new();
-    let mut script_language_docids = HashMap::new();
+    let mut del_script_language_docids = HashMap::new();
+    let mut add_script_language_docids = HashMap::new();
     let mut docid_word_positions_sorter = create_sorter(
         grenad::SortAlgorithm::Stable,
         keep_latest_obkv,
@@ -48,7 +54,142 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
         max_memory,
     );
 
-    let mut buffers = Buffers::default();
+    // initialize buffers.
+    let mut del_buffers = Buffers::default();
+    let mut add_buffers = Buffers::default();
+    let mut key_buffer = Vec::new();
+    let mut value_buffer = Vec::new();
+
+    // initialize tokenizer.
+    let mut builder = tokenizer_builder(stop_words, dictionary, allowed_separators, None);
+    let tokenizer = builder.build();
+
+    // iterate over documents.
+    let mut cursor = obkv_documents.into_cursor()?;
+    while let Some((key, value)) = cursor.move_on_next()? {
+        let document_id = key
+            .try_into()
+            .map(u32::from_be_bytes)
+            .map_err(|_| SerializationError::InvalidNumberSerialization)?;
+        let obkv = KvReader::<FieldId>::new(value);
+
+        // if the searchable fields didn't change, skip the searchable indexing for this document.
+        if !searchable_fields_changed(&KvReader::<FieldId>::new(value), searchable_fields) {
+            continue;
+        }
+
+        documents_ids.push(document_id);
+
+        // Update key buffer prefix.
+        key_buffer.clear();
+        key_buffer.extend_from_slice(&document_id.to_be_bytes());
+
+        // Tokenize deletions and additions in 2 diffferent threads.
+        let (del, add): (Result<_>, Result<_>) = rayon::join(
+            || {
+                // deletions
+                lang_safe_tokens_from_document(
+                    &obkv,
+                    searchable_fields,
+                    &tokenizer,
+                    stop_words,
+                    allowed_separators,
+                    dictionary,
+                    max_positions_per_attributes,
+                    DelAdd::Deletion,
+                    &mut del_buffers,
+                )
+            },
+            || {
+                // additions
+                lang_safe_tokens_from_document(
+                    &obkv,
+                    searchable_fields,
+                    &tokenizer,
+                    stop_words,
+                    allowed_separators,
+                    dictionary,
+                    max_positions_per_attributes,
+                    DelAdd::Addition,
+                    &mut add_buffers,
+                )
+            },
+        );
+
+        let (del_obkv, del_script_language_word_count) = del?;
+        let (add_obkv, add_script_language_word_count) = add?;
+
+        // merge deletions and additions.
+        value_buffer.clear();
+        del_add_from_two_obkvs(
+            KvReader::<FieldId>::new(del_obkv),
+            KvReader::<FieldId>::new(add_obkv),
+            &mut value_buffer,
+        )?;
+
+        // write them into the sorter.
+        let obkv = KvReader::<FieldId>::new(value);
+        for (field_id, value) in obkv.iter() {
+            key_buffer.truncate(mem::size_of::<u32>());
+            key_buffer.extend_from_slice(&field_id.to_be_bytes());
+            docid_word_positions_sorter.insert(&key_buffer, value)?;
+        }
+
+        // update script_language_docids deletions.
+        for (script, languages_frequency) in del_script_language_word_count {
+            for (language, _) in languages_frequency {
+                let entry = del_script_language_docids
+                    .entry((script, language))
+                    .or_insert_with(RoaringBitmap::new);
+                entry.push(document_id);
+            }
+        }
+
+        // update script_language_docids additions.
+        for (script, languages_frequency) in add_script_language_word_count {
+            for (language, _) in languages_frequency {
+                let entry = add_script_language_docids
+                    .entry((script, language))
+                    .or_insert_with(RoaringBitmap::new);
+                entry.push(document_id);
+            }
+        }
+    }
+
+    let script_language_docids = (del_script_language_docids, add_script_language_docids);
+    sorter_into_reader(docid_word_positions_sorter, indexer)
+        .map(|reader| (documents_ids, reader, script_language_docids))
+}
+
+/// Check if any searchable fields of a document changed.
+fn searchable_fields_changed(
+    obkv: &KvReader<FieldId>,
+    searchable_fields: &Option<HashSet<FieldId>>,
+) -> bool {
+    for (field_id, field_bytes) in obkv.iter() {
+        if searchable_fields.as_ref().map_or(true, |sf| sf.contains(&field_id)) {
+            let del_add = KvReaderDelAdd::new(field_bytes);
+            match (del_add.get(DelAdd::Deletion), del_add.get(DelAdd::Addition)) {
+                // if both fields are None, check the next field.
+                (None, None) => (),
+                // if both contains a value and values are the same, check the next field.
+                (Some(del), Some(add)) if del == add => (),
+                // otherwise the fields are different, return true.
+                _otherwise => return true,
+            }
+        }
+    }
+
+    false
+}
+
+/// Factorize tokenizer building.
+fn tokenizer_builder<'a>(
+    stop_words: Option<&'a fst::Set<&[u8]>>,
+    allowed_separators: Option<&'a [&str]>,
+    dictionary: Option<&'a [&str]>,
+    script_language: Option<&'a HashMap<Script, Vec<Language>>>,
+) -> TokenizerBuilder<'a, &'a [u8]> {
     let mut tokenizer_builder = TokenizerBuilder::new();
     if let Some(stop_words) = stop_words {
         tokenizer_builder.stop_words(stop_words);
@@ -59,138 +200,144 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
     if let Some(separators) = allowed_separators {
         tokenizer_builder.separators(separators);
     }
-    let tokenizer = tokenizer_builder.build();
 
-    let mut cursor = obkv_documents.into_cursor()?;
-    while let Some((key, value)) = cursor.move_on_next()? {
-        let document_id = key
-            .try_into()
-            .map(u32::from_be_bytes)
-            .map_err(|_| SerializationError::InvalidNumberSerialization)?;
-        let obkv = KvReader::<FieldId>::new(value);
+    if let Some(script_language) = script_language {
+        tokenizer_builder.allow_list(&script_language);
+    }
 
-        documents_ids.push(document_id);
-        buffers.key_buffer.clear();
-        buffers.key_buffer.extend_from_slice(&document_id.to_be_bytes());
+    tokenizer_builder
+}
 
-        let mut script_language_word_count = HashMap::new();
+/// Extract words maped with their positions of a document,
+/// ensuring no Language detection mistakes was made.
+fn lang_safe_tokens_from_document<'a>(
+    obkv: &KvReader<FieldId>,
+    searchable_fields: &Option<HashSet<FieldId>>,
+    tokenizer: &Tokenizer,
+    stop_words: Option<&fst::Set<&[u8]>>,
+    allowed_separators: Option<&[&str]>,
+    dictionary: Option<&[&str]>,
+    max_positions_per_attributes: u32,
+    del_add: DelAdd,
+    buffers: &'a mut Buffers,
+) -> Result<(&'a [u8], HashMap<Script, Vec<(Language, usize)>>)> {
+    let mut script_language_word_count = HashMap::new();
 
-        extract_tokens_from_document(
-            &obkv,
-            searchable_fields,
-            &tokenizer,
-            max_positions_per_attributes,
-            &mut buffers,
-            &mut script_language_word_count,
-            &mut docid_word_positions_sorter,
-        )?;
+    tokens_from_document(
+        &obkv,
+        searchable_fields,
+        &tokenizer,
+        max_positions_per_attributes,
+        del_add,
+        buffers,
+        &mut script_language_word_count,
+    )?;
 
-        // if we detect a potetial mistake in the language detection,
-        // we rerun the extraction forcing the tokenizer to detect the most frequently detected Languages.
-        // context: https://github.com/meilisearch/meilisearch/issues/3565
-        if script_language_word_count
-            .values()
-            .map(Vec::as_slice)
-            .any(potential_language_detection_error)
-        {
-            // build an allow list with the most frequent detected languages in the document.
-            let script_language: HashMap<_, _> =
-                script_language_word_count.iter().filter_map(most_frequent_languages).collect();
+    // if we detect a potetial mistake in the language detection,
+    // we rerun the extraction forcing the tokenizer to detect the most frequently detected Languages.
+    // context: https://github.com/meilisearch/meilisearch/issues/3565
+    if script_language_word_count
+        .values()
+        .map(Vec::as_slice)
+        .any(potential_language_detection_error)
+    {
+        // build an allow list with the most frequent detected languages in the document.
+        let script_language: HashMap<_, _> =
+            script_language_word_count.iter().filter_map(most_frequent_languages).collect();
 
-            // if the allow list is empty, meaning that no Language is considered frequent,
-            // then we don't rerun the extraction.
-            if !script_language.is_empty() {
-                // build a new temporary tokenizer including the allow list.
-                let mut tokenizer_builder = TokenizerBuilder::new();
-                if let Some(stop_words) = stop_words {
-                    tokenizer_builder.stop_words(stop_words);
-                }
-                if let Some(dictionary) = dictionary {
-                    tokenizer_builder.words_dict(dictionary);
-                }
-                if let Some(separators) = allowed_separators {
-                    tokenizer_builder.separators(separators);
-                }
-                tokenizer_builder.allow_list(&script_language);
-                let tokenizer = tokenizer_builder.build();
+        // if the allow list is empty, meaning that no Language is considered frequent,
+        // then we don't rerun the extraction.
+        if !script_language.is_empty() {
+            // build a new temporary tokenizer including the allow list.
+            let mut builder = tokenizer_builder(
+                stop_words,
+                dictionary,
+                allowed_separators,
+                Some(&script_language),
+            );
+            let tokenizer = builder.build();
 
-                script_language_word_count.clear();
+            script_language_word_count.clear();
 
-                // rerun the extraction.
-                extract_tokens_from_document(
-                    &obkv,
-                    searchable_fields,
-                    &tokenizer,
-                    max_positions_per_attributes,
-                    &mut buffers,
-                    &mut script_language_word_count,
-                    &mut docid_word_positions_sorter,
-                )?;
-            }
-        }
-
-        for (script, languages_frequency) in script_language_word_count {
-            for (language, _) in languages_frequency {
-                let entry = script_language_docids
-                    .entry((script, language))
-                    .or_insert_with(RoaringBitmap::new);
-                entry.push(document_id);
-            }
+            // rerun the extraction.
+            tokens_from_document(
+                &obkv,
+                searchable_fields,
+                &tokenizer,
+                max_positions_per_attributes,
+                del_add,
+                buffers,
+                &mut script_language_word_count,
+            )?;
         }
     }
 
-    sorter_into_reader(docid_word_positions_sorter, indexer)
-        .map(|reader| (documents_ids, reader, script_language_docids))
+    Ok((&buffers.obkv_buffer, script_language_word_count))
 }
 
-fn extract_tokens_from_document(
+/// Extract words maped with their positions of a document.
+fn tokens_from_document<'a>(
     obkv: &KvReader<FieldId>,
     searchable_fields: &Option<HashSet<FieldId>>,
     tokenizer: &Tokenizer,
     max_positions_per_attributes: u32,
-    buffers: &mut Buffers,
+    del_add: DelAdd,
+    buffers: &'a mut Buffers,
     script_language_word_count: &mut HashMap<Script, Vec<(Language, usize)>>,
-    docid_word_positions_sorter: &mut grenad::Sorter<MergeFn>,
-) -> Result<()> {
+) -> Result<&'a [u8]> {
+    buffers.obkv_buffer.clear();
+    let mut document_writer = KvWriterU16::new(&mut buffers.obkv_buffer);
     for (field_id, field_bytes) in obkv.iter() {
+        // if field is searchable.
         if searchable_fields.as_ref().map_or(true, |sf| sf.contains(&field_id)) {
-            let value = serde_json::from_slice(field_bytes).map_err(InternalError::SerdeJson)?;
-            buffers.field_buffer.clear();
-            if let Some(field) = json_to_string(&value, &mut buffers.field_buffer) {
-                let tokens = process_tokens(tokenizer.tokenize(field))
-                    .take_while(|(p, _)| (*p as u32) < max_positions_per_attributes);
+            // extract deletion or addition only.
+            if let Some(field_bytes) = KvReaderDelAdd::new(field_bytes).get(del_add) {
+                // parse json.
+                let value =
+                    serde_json::from_slice(field_bytes).map_err(InternalError::SerdeJson)?;
 
-                buffers.obkv_buffer.clear();
-                let mut writer = KvWriterU16::new(&mut buffers.obkv_buffer);
-                for (index, token) in tokens {
-                    // if a language has been detected for the token, we update the counter.
-                    if let Some(language) = token.language {
-                        let script = token.script;
-                        let entry =
-                            script_language_word_count.entry(script).or_insert_with(Vec::new);
-                        match entry.iter_mut().find(|(l, _)| *l == language) {
-                            Some((_, n)) => *n += 1,
-                            None => entry.push((language, 1)),
+                // prepare writting destination.
+                buffers.obkv_positions_buffer.clear();
+                let mut writer = KvWriterU16::new(&mut buffers.obkv_positions_buffer);
+
+                // convert json into an unique string.
+                buffers.field_buffer.clear();
+                if let Some(field) = json_to_string(&value, &mut buffers.field_buffer) {
+                    // create an iterator of token with their positions.
+                    let tokens = process_tokens(tokenizer.tokenize(field))
+                        .take_while(|(p, _)| (*p as u32) < max_positions_per_attributes);
+
+                    for (index, token) in tokens {
+                        // if a language has been detected for the token, we update the counter.
+                        if let Some(language) = token.language {
+                            let script = token.script;
+                            let entry =
+                                script_language_word_count.entry(script).or_insert_with(Vec::new);
+                            match entry.iter_mut().find(|(l, _)| *l == language) {
+                                Some((_, n)) => *n += 1,
+                                None => entry.push((language, 1)),
+                            }
+                        }
+
+                        // keep a word only if it is not empty and fit in a LMDB key.
+                        let token = token.lemma().trim();
+                        if !token.is_empty() && token.len() <= MAX_WORD_LENGTH {
+                            let position: u16 = index
+                                .try_into()
+                                .map_err(|_| SerializationError::InvalidNumberSerialization)?;
+                            writer.insert(position, token.as_bytes())?;
                         }
                     }
-                    let token = token.lemma().trim();
-                    if !token.is_empty() && token.len() <= MAX_WORD_LENGTH {
-                        let position: u16 = index
-                            .try_into()
-                            .map_err(|_| SerializationError::InvalidNumberSerialization)?;
-                        writer.insert(position, token.as_bytes())?;
-                    }
-                }
 
-                let positions = writer.into_inner()?;
-                buffers.key_buffer.truncate(mem::size_of::<u32>());
-                buffers.key_buffer.extend_from_slice(&field_id.to_be_bytes());
-                docid_word_positions_sorter.insert(&buffers.key_buffer, positions)?;
+                    // write positions into document.
+                    let positions = writer.into_inner()?;
+                    document_writer.insert(field_id, positions)?;
+                }
             }
         }
     }
 
-    Ok(())
+    Ok(document_writer.into_inner().map(|v| v.as_slice())?)
 }
 
 /// Transform a JSON value into a string that can be indexed.
@@ -293,12 +440,10 @@ fn compute_language_frequency_threshold(languages_frequency: &[(Language, usize)
 
 #[derive(Default)]
 struct Buffers {
-    // the key buffer is the concatenation of the internal document id with the field id.
-    // The buffer has to be completelly cleared between documents,
-    // and the field id part must be cleared between each field.
-    key_buffer: Vec<u8>,
     // the field buffer for each fields desserialization, and must be cleared between each field.
     field_buffer: String,
     // buffer used to store the value data containing an obkv.
     obkv_buffer: Vec<u8>,
+    // buffer used to store the value data containing an obkv of tokens with their positions.
+    obkv_positions_buffer: Vec<u8>,
 }

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

@@ -117,8 +117,9 @@ pub fn merge_two_del_add_obkvs(
                 let update_reader = KvReaderDelAdd::new(update);
 
                 // keep newest deletion.
-                if let Some(deletion) =
-                    update_reader.get(DelAdd::Deletion).or(base_reader.get(DelAdd::Deletion))
+                if let Some(deletion) = update_reader
+                    .get(DelAdd::Deletion)
+                    .or_else(|| base_reader.get(DelAdd::Deletion))
                 {
                     value_writer.insert(DelAdd::Deletion, deletion).unwrap();
                 }
@@ -127,6 +128,7 @@ pub fn merge_two_del_add_obkvs(
                 let base_addition =
                     merge_additions.then(|| base_reader.get(DelAdd::Addition)).flatten();
                 // keep newest addition.
+                // TODO use or_else
                 if let Some(addition) = update_reader.get(DelAdd::Addition).or(base_addition) {
                     value_writer.insert(DelAdd::Addition, addition).unwrap();
                 }

milli/src/update/index_documents/transform.rs

@@ -805,7 +805,7 @@ impl<'a, 'i> Transform<'a, 'i> {
 
             let buffer = obkv_writer.into_inner()?;
             document_sorter_buffer.clear();
-            into_del_add_obkv(KvReaderU16::new(buffer), true, true, &mut document_sorter_buffer)?;
+            into_del_add_obkv(KvReaderU16::new(buffer), false, true, &mut document_sorter_buffer)?;
             original_writer.insert(docid.to_be_bytes(), &document_sorter_buffer)?;
 
             // Once we have the document. We're going to flatten it
@@ -842,7 +842,7 @@ impl<'a, 'i> Transform<'a, 'i> {
                 writer.insert(fid, &value)?;
             }
             document_sorter_buffer.clear();
-            into_del_add_obkv(KvReaderU16::new(&buffer), true, true, &mut document_sorter_buffer)?;
+            into_del_add_obkv(KvReaderU16::new(&buffer), false, true, &mut document_sorter_buffer)?;
             flattened_writer.insert(docid.to_be_bytes(), &document_sorter_buffer)?;
         }
 

milli/src/update/index_documents/typed_chunk.rs

@@ -43,7 +43,9 @@ pub(crate) enum TypedChunk {
     FieldIdFacetIsEmptyDocids(grenad::Reader<BufReader<File>>),
     GeoPoints(grenad::Reader<BufReader<File>>),
     VectorPoints(grenad::Reader<BufReader<File>>),
-    ScriptLanguageDocids(HashMap<(Script, Language), RoaringBitmap>),
+    ScriptLanguageDocids(
+        (HashMap<(Script, Language), RoaringBitmap>, HashMap<(Script, Language), RoaringBitmap>),
+    ),
 }
 
 impl TypedChunk {
@@ -101,8 +103,8 @@ impl TypedChunk {
             TypedChunk::VectorPoints(grenad) => {
                 format!("VectorPoints {{ number_of_entries: {} }}", grenad.len())
             }
-            TypedChunk::ScriptLanguageDocids(grenad) => {
-                format!("ScriptLanguageDocids {{ number_of_entries: {} }}", grenad.len())
+            TypedChunk::ScriptLanguageDocids((_, addition)) => {
+                format!("ScriptLanguageDocids {{ number_of_entries: {} }}", addition.len())
             }
         }
     }
@@ -344,19 +346,21 @@ pub(crate) fn write_typed_chunk_into_index(
             log::debug!("There are {} entries in the HNSW so far", hnsw_length);
             index.put_vector_hnsw(wtxn, &new_hnsw)?;
         }
-        TypedChunk::ScriptLanguageDocids(hash_pair) => {
-            let mut buffer = Vec::new();
-            for (key, value) in hash_pair {
-                buffer.clear();
-                let final_value = match index.script_language_docids.get(wtxn, &key)? {
-                    Some(db_values) => {
-                        let mut db_value_buffer = Vec::new();
-                        serialize_roaring_bitmap(&db_values, &mut db_value_buffer)?;
-                        let mut new_value_buffer = Vec::new();
-                        serialize_roaring_bitmap(&value, &mut new_value_buffer)?;
-                        merge_roaring_bitmaps(&new_value_buffer, &db_value_buffer, &mut buffer)?;
-                        RoaringBitmap::deserialize_from(&buffer[..])?
+        TypedChunk::ScriptLanguageDocids((deletion, addition)) => {
+            for (key, value) in deletion {
+                if let Some(mut db_values) = index.script_language_docids.get(wtxn, &key)? {
+                    db_values -= value;
+                    if db_values.is_empty() {
+                        index.script_language_docids.delete(wtxn, &key)?;
+                    } else {
+                        index.script_language_docids.put(wtxn, &key, &db_values)?;
                     }
+                }
+            }
+
+            for (key, value) in addition {
+                let final_value = match index.script_language_docids.get(wtxn, &key)? {
+                    Some(mut db_values) => db_values | value,
                     None => value,
                 };
                 index.script_language_docids.put(wtxn, &key, &final_value)?;