diff --git a/milli/src/update/index_documents/cache.rs b/milli/src/update/index_documents/cache.rs
index cd633670b..51adf4ee5 100644
--- a/milli/src/update/index_documents/cache.rs
+++ b/milli/src/update/index_documents/cache.rs
@@ -11,6 +11,7 @@ use crate::CboRoaringBitmapCodec;
 
 pub struct SorterCacheDelAddCboRoaringBitmap<const N: usize, MF> {
     cache: LruCache<SmallVec<[u8; N]>, DelAddRoaringBitmap>,
+    prefix: &'static [u8; 3],
     sorter: grenad::Sorter<MF>,
     deladd_buffer: Vec<u8>,
     cbo_buffer: Vec<u8>,
@@ -18,9 +19,15 @@ pub struct SorterCacheDelAddCboRoaringBitmap<const N: usize, MF> {
 }
 
 impl<const N: usize, MF> SorterCacheDelAddCboRoaringBitmap<N, MF> {
-    pub fn new(cap: NonZeroUsize, sorter: grenad::Sorter<MF>, conn: redis::Connection) -> Self {
+    pub fn new(
+        cap: NonZeroUsize,
+        sorter: grenad::Sorter<MF>,
+        prefix: &'static [u8; 3],
+        conn: redis::Connection,
+    ) -> Self {
         SorterCacheDelAddCboRoaringBitmap {
             cache: LruCache::new(cap),
+            prefix,
             sorter,
             deladd_buffer: Vec::new(),
             cbo_buffer: Vec::new(),
@@ -136,7 +143,10 @@ where
             }
             DelAddRoaringBitmap { del: None, add: None } => return Ok(()),
         }
-        redis::cmd("INCR").arg(key.as_ref()).query::<usize>(&mut self.conn).unwrap();
+        self.cbo_buffer.clear();
+        self.cbo_buffer.extend_from_slice(self.prefix);
+        self.cbo_buffer.extend_from_slice(&key);
+        redis::cmd("INCR").arg(&self.cbo_buffer).query::<usize>(&mut self.conn).unwrap();
         self.sorter.insert(key, value_writer.into_inner().unwrap())
     }
 
diff --git a/milli/src/update/index_documents/extract/extract_facet_number_docids.rs b/milli/src/update/index_documents/extract/extract_facet_number_docids.rs
index 6c6243663..f36903b8f 100644
--- a/milli/src/update/index_documents/extract/extract_facet_number_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_facet_number_docids.rs
@@ -40,6 +40,7 @@ pub fn extract_facet_number_docids<R: io::Read + io::Seek>(
         SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
             NonZeroUsize::new(20).unwrap(),
             facet_number_docids_sorter,
+            b"fnd",
             super::REDIS_CLIENT.get_connection().unwrap(),
         );
 
diff --git a/milli/src/update/index_documents/extract/extract_facet_string_docids.rs b/milli/src/update/index_documents/extract/extract_facet_string_docids.rs
index a618b065f..da6b8fd82 100644
--- a/milli/src/update/index_documents/extract/extract_facet_string_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_facet_string_docids.rs
@@ -48,6 +48,7 @@ pub fn extract_facet_string_docids<R: io::Read + io::Seek>(
         SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
             NonZeroUsize::new(200).unwrap(),
             facet_string_docids_sorter,
+            b"fsd",
             REDIS_CLIENT.get_connection().unwrap(),
         );
 
diff --git a/milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs b/milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs
index cb1dcea51..49de09eee 100644
--- a/milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_fid_word_count_docids.rs
@@ -43,6 +43,7 @@ pub fn extract_fid_word_count_docids<R: io::Read + io::Seek>(
         SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
             NonZeroUsize::new(300).unwrap(),
             fid_word_count_docids_sorter,
+            b"fwc",
             super::REDIS_CLIENT.get_connection().unwrap(),
         );
 
diff --git a/milli/src/update/index_documents/extract/extract_word_docids.rs b/milli/src/update/index_documents/extract/extract_word_docids.rs
index dbe52e426..fca9ca3b1 100644
--- a/milli/src/update/index_documents/extract/extract_word_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_word_docids.rs
@@ -52,6 +52,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
     let mut cached_word_fid_docids_sorter = SorterCacheDelAddCboRoaringBitmap::<20, _>::new(
         NonZeroUsize::new(300).unwrap(),
         word_fid_docids_sorter,
+        b"wfd",
         REDIS_CLIENT.get_connection().unwrap(),
     );
 
@@ -112,6 +113,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
     let mut cached_word_docids_sorter = SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
         NonZeroUsize::new(100).unwrap(),
         word_docids_sorter,
+        b"wdi",
         REDIS_CLIENT.get_connection().unwrap(),
     );
 
@@ -126,6 +128,7 @@ pub fn extract_word_docids<R: io::Read + io::Seek>(
     let mut cached_exact_word_docids_sorter = SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
         NonZeroUsize::new(100).unwrap(),
         exact_word_docids_sorter,
+        b"ewd",
         REDIS_CLIENT.get_connection().unwrap(),
     );
 
diff --git a/milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs b/milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs
index 881a17818..6b7a2496c 100644
--- a/milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs
@@ -55,6 +55,7 @@ pub fn extract_word_pair_proximity_docids<R: io::Read + io::Seek>(
             SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
                 NonZeroUsize::new(100).unwrap(),
                 sorter,
+                b"wpp",
                 super::REDIS_CLIENT.get_connection().unwrap(),
             )
         })
diff --git a/milli/src/update/index_documents/extract/extract_word_position_docids.rs b/milli/src/update/index_documents/extract/extract_word_position_docids.rs
index ecdd62df0..7343b6e6b 100644
--- a/milli/src/update/index_documents/extract/extract_word_position_docids.rs
+++ b/milli/src/update/index_documents/extract/extract_word_position_docids.rs
@@ -41,6 +41,7 @@ pub fn extract_word_position_docids<R: io::Read + io::Seek>(
         SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
             NonZeroUsize::new(300).unwrap(),
             word_position_docids_sorter,
+            b"wpd",
             super::REDIS_CLIENT.get_connection().unwrap(),
         );
 
diff --git a/milli/src/update/word_prefix_docids.rs b/milli/src/update/word_prefix_docids.rs
index 4326a380c..c551642ba 100644
--- a/milli/src/update/word_prefix_docids.rs
+++ b/milli/src/update/word_prefix_docids.rs
@@ -68,6 +68,7 @@ impl<'t, 'i> WordPrefixDocids<'t, 'i> {
         let mut cached_prefix_docids_sorter = SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
             NonZeroUsize::new(200).unwrap(),
             prefix_docids_sorter,
+            b"pdi",
             REDIS_CLIENT.get_connection().unwrap(),
         );
 
diff --git a/milli/src/update/words_prefix_integer_docids.rs b/milli/src/update/words_prefix_integer_docids.rs
index 8e6e957ce..038882530 100644
--- a/milli/src/update/words_prefix_integer_docids.rs
+++ b/milli/src/update/words_prefix_integer_docids.rs
@@ -73,6 +73,7 @@ impl<'t, 'i> WordPrefixIntegerDocids<'t, 'i> {
             SorterCacheDelAddCboRoaringBitmap::<20, MergeFn>::new(
                 NonZeroUsize::new(200).unwrap(),
                 prefix_integer_docids_sorter,
+                b"pid",
                 REDIS_CLIENT.get_connection().unwrap(),
             );