Expose a new indexer parameter to enable the creation of a document dictionary

crates/milli/src/update/new/extract/documents/compression.rs

@@ -60,6 +60,7 @@ where
     let number_of_documents = index.number_of_documents(wtxn)? as usize;
     match index.document_compression_raw_dictionary(wtxn)? {
         Some(dict) => Ok(Some(EncoderDictionary::copy(dict, COMPRESSION_LEVEL))),
+        None if !indexing_context.allow_creating_compression_dictionary => Ok(None),
         None if number_of_documents >= COMPRESS_LIMIT => Ok(None),
         None if number_of_documents + document_changes.len() < SAMPLE_SIZE => Ok(None),
         None => {

crates/milli/src/update/new/indexer/document_changes.rs

@@ -146,6 +146,7 @@ pub struct IndexingContext<
 {
     pub index: &'index Index,
     pub db_fields_ids_map: &'indexer FieldsIdsMap,
+    pub allow_creating_compression_dictionary: bool,
     pub db_document_decompression_dictionary: Option<&'indexer DecoderDictionary<'static>>,
     pub new_fields_ids_map: &'fid RwLock<FieldIdMapWithMetadata>,
     pub doc_allocs: &'indexer ThreadLocal<FullySend<Cell<Bump>>>,
@@ -210,6 +211,7 @@ pub fn extract<
     IndexingContext {
         index,
         db_fields_ids_map,
+        allow_creating_compression_dictionary,
         db_document_decompression_dictionary,
         new_fields_ids_map,
         doc_allocs,

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

@@ -108,6 +108,7 @@ where
     let indexing_context = IndexingContext {
         index,
         db_fields_ids_map,
+        allow_creating_compression_dictionary,
         db_document_decompression_dictionary: db_document_decompression_dictionary.as_ref(),
         new_fields_ids_map: &new_fields_ids_map,
         doc_allocs: &doc_allocs,