limit extract_word_docids memory usage

milli/src/update/delete_documents.rs

@@ -502,6 +502,7 @@ fn remove_from_word_docids(
             }
         }
     }
+
     Ok(())
 }
 

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

@@ -34,7 +34,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
         indexer.chunk_compression_type,
         indexer.chunk_compression_level,
         indexer.max_nb_chunks,
-        max_memory,
+        max_memory.map(|x| x / 2),
     );
 
     let mut exact_word_docids_sorter = create_sorter(
@@ -42,7 +42,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
         indexer.chunk_compression_type,
         indexer.chunk_compression_level,
         indexer.max_nb_chunks,
-        max_memory,
+        max_memory.map(|x| x / 2),
     );
 
     let mut value_buffer = Vec::new();