diff --git a/Cargo.toml b/Cargo.toml
index eac65404d..79707af9e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -43,7 +43,6 @@ criterion = "0.3"
 
 [features]
 default = []
-intersect-to-csv = []
 
 [[bench]]
 name = "search"
diff --git a/src/lib.rs b/src/lib.rs
index c24c77563..ead9ee278 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -123,68 +123,42 @@ impl Index {
 
         let mut documents = Vec::new();
 
-        let mut debug_intersects = HashMap::new();
+        // Returns the union of the same position for all the derived words.
+        let unions_word_pos = |word: usize, pos: u32| {
+            let mut union_docids = RoaringBitmap::new();
+            for (word, attrs) in &words[word] {
+                if attrs.contains(pos) {
+                    let mut key = word.clone();
+                    key.extend_from_slice(&pos.to_be_bytes());
+                    if let Some(attrs) = self.postings_ids.get(rtxn, &key).unwrap() {
+                        let right = RoaringBitmap::deserialize_from_slice(attrs).unwrap();
+                        union_docids.union_with(&right);
+                    }
+                }
+            }
+
+            union_docids
+        };
+
+        let mut union_cache = HashMap::new();
         let mut intersect_cache = HashMap::new();
-        let mut lunion_docids = RoaringBitmap::default();
-        let mut runion_docids = RoaringBitmap::default();
+        // Returns `true` if there is documents in common between the two words and positions given.
         let contains_documents = |(lword, lpos): (usize, u32), (rword, rpos): (usize, u32)| {
             let proximity = best_proximity::positions_proximity(lpos, rpos);
+
             if proximity == 0 { return false }
 
+            // We retrieve or compute the intersection between the two given words and positions.
             *intersect_cache.entry(((lword, lpos), (rword, rpos))).or_insert_with(|| {
-                let (nb_words, nb_docs_intersect, lnblookups, lnbbitmaps, rnblookups, rnbbitmaps) =
-                    debug_intersects.entry((lword, lpos, rword, rpos, proximity)).or_default();
+                // We retrieve or compute the unions for the two words and positions.
+                union_cache.entry((lword, lpos)).or_insert_with(|| unions_word_pos(lword, lpos));
+                union_cache.entry((rword, rpos)).or_insert_with(|| unions_word_pos(rword, rpos));
 
-                let left = &words[lword];
-                let right = &words[rword];
+                // TODO is there a way to avoid this double gets?
+                let lunion_docids = union_cache.get(&(lword, lpos)).unwrap();
+                let runion_docids = union_cache.get(&(rword, rpos)).unwrap();
 
-                *nb_words = left.len() + right.len();
-
-                let mut l_lookups = 0;
-                let mut l_bitmaps = 0;
-                let mut r_lookups = 0;
-                let mut r_bitmaps = 0;
-
-                // This for the left word
-                lunion_docids.clear();
-                for (word, attrs) in left {
-                    if attrs.contains(lpos) {
-                        l_lookups += 1;
-                        let mut key = word.clone();
-                        key.extend_from_slice(&lpos.to_be_bytes());
-                        if let Some(attrs) = self.postings_ids.get(rtxn, &key).unwrap() {
-                            l_bitmaps += 1;
-                            let right = RoaringBitmap::deserialize_from_slice(attrs).unwrap();
-                            lunion_docids.union_with(&right);
-                        }
-                    }
-                }
-
-                // This for the right word
-                runion_docids.clear();
-                for (word, attrs) in right {
-                    if attrs.contains(rpos) {
-                        r_lookups += 1;
-                        let mut key = word.clone();
-                        key.extend_from_slice(&rpos.to_be_bytes());
-                        if let Some(attrs) = self.postings_ids.get(rtxn, &key).unwrap() {
-                            r_bitmaps += 1;
-                            let right = RoaringBitmap::deserialize_from_slice(attrs).unwrap();
-                            runion_docids.union_with(&right);
-                        }
-                    }
-                }
-
-                let intersect_docids = &mut lunion_docids;
-                intersect_docids.intersect_with(&runion_docids);
-
-                *lnblookups = l_lookups;
-                *lnbbitmaps = l_bitmaps;
-                *rnblookups = r_lookups;
-                *rnbbitmaps = r_bitmaps;
-                *nb_docs_intersect += intersect_docids.len();
-
-                !intersect_docids.is_empty()
+                !lunion_docids.is_disjoint(&runion_docids)
             })
         };
 
@@ -262,65 +236,7 @@ impl Index {
             }
         }
 
-        if cfg!(feature = "intersect-to-csv") {
-            debug_intersects_to_csv(debug_intersects);
-        }
-
         eprintln!("{} candidates", documents.iter().map(RoaringBitmap::len).sum::<u64>());
         Ok(documents.iter().flatten().take(20).collect())
     }
 }
-
-fn debug_intersects_to_csv(intersects: HashMap<(usize, u32, usize, u32, u32), (usize, u64, usize, usize, usize, usize)>) {
-    let mut wrt = csv::Writer::from_path("intersects-stats.csv").unwrap();
-    wrt.write_record(&[
-        "proximity",
-        "lword",
-        "lpos",
-        "rword",
-        "rpos",
-        "nb_derived_words",
-        "nb_docs_intersect",
-        "lnblookups",
-        "lnbbitmaps",
-        "rnblookups",
-        "rnbbitmaps",
-    ]).unwrap();
-
-    for ((lword, lpos, rword, rpos, proximity), vals) in intersects {
-        let (
-            nb_derived_words,
-            nb_docs_intersect,
-            lnblookups,
-            lnbbitmaps,
-            rnblookups,
-            rnbbitmaps,
-        ) = vals;
-
-        let proximity = proximity.to_string();
-        let lword = lword.to_string();
-        let lpos = lpos.to_string();
-        let rword = rword.to_string();
-        let rpos = rpos.to_string();
-        let nb_derived_words = nb_derived_words.to_string();
-        let nb_docs_intersect = nb_docs_intersect.to_string();
-        let lnblookups = lnblookups.to_string();
-        let lnbbitmaps = lnbbitmaps.to_string();
-        let rnblookups = rnblookups.to_string();
-        let rnbbitmaps = rnbbitmaps.to_string();
-
-        wrt.write_record(&[
-            &proximity,
-            &lword,
-            &lpos,
-            &rword,
-            &rpos,
-            &nb_derived_words,
-            &nb_docs_intersect,
-            &lnblookups,
-            &lnbbitmaps,
-            &rnblookups,
-            &rnbbitmaps,
-        ]).unwrap();
-    }
-}