diff --git a/core/dr-catalog/src/merge.rs b/core/dr-catalog/src/merge.rs
index 5da149a..fcc4947 100644
--- a/core/dr-catalog/src/merge.rs
+++ b/core/dr-catalog/src/merge.rs
@@ -725,6 +725,15 @@ fn merge_keywords_within(tx: &Connection, report: &mut MergeReport) -> Result<()
 /// version arrives through there, the default version is both where
 /// [`crate::keywords::assign`] writes and where the panel reads — so it is the
 /// one place the word can land and be seen.
+///
+/// A word is refused when this device holds it only as a tombstone: deleted
+/// under some identity and live under none. That is a set of words, the same
+/// for every row, so it is asked once -- a list SQLite builds before the walk
+/// -- rather than as a correlated `NOT EXISTS ... OR EXISTS` per incoming
+/// assignment. The `deleted = 1` half of that could use no index
+/// (`keyword_terms_name` holds only live rows) and scanned the whole
+/// vocabulary for each of 10,800 assignments: 70 ms of a sync pass that
+/// changed nothing, on the reference library, against 11 ms now.
 const ASSIGN_BY_FILE_ID: &str = "
     INSERT OR IGNORE INTO main.keywords(version_id, keyword)
     SELECT lv.id, rk.keyword
@@ -733,10 +742,9 @@ const ASSIGN_BY_FILE_ID: &str = "
       JOIN remote_cat.remote   rr ON rr.image_id = rv.image_id
       JOIN main.remote         lr ON lr.file_id = rr.file_id
       JOIN main.versions       lv ON lv.image_id = lr.image_id AND lv.is_default = 1
-     WHERE NOT EXISTS (SELECT 1 FROM main.keyword_terms t
-                        WHERE t.name = rk.keyword AND t.deleted = 1)
-        OR EXISTS      (SELECT 1 FROM main.keyword_terms t
-                        WHERE t.name = rk.keyword AND t.deleted = 0)";
+     WHERE rk.keyword NOT IN (SELECT name FROM main.keyword_terms WHERE deleted = 1
+                              EXCEPT
+                              SELECT name FROM main.keyword_terms WHERE deleted = 0)";
 
 /// The same union for a library with no server behind it.
 ///
@@ -753,10 +761,9 @@ const ASSIGN_BY_CONTENT_HASH: &str = "
       JOIN main.images         li ON li.content_hash = ri.content_hash
       JOIN main.versions       lv ON lv.image_id = li.id AND lv.is_default = 1
      WHERE ri.content_hash IS NOT NULL
-       AND (NOT EXISTS (SELECT 1 FROM main.keyword_terms t
-                         WHERE t.name = rk.keyword AND t.deleted = 1)
-            OR EXISTS  (SELECT 1 FROM main.keyword_terms t
-                         WHERE t.name = rk.keyword AND t.deleted = 0))";
+       AND rk.keyword NOT IN (SELECT name FROM main.keyword_terms WHERE deleted = 1
+                              EXCEPT
+                              SELECT name FROM main.keyword_terms WHERE deleted = 0)";
 
 /// Whether an attached database holds a table of this name.
 ///