diff --git a/src/libstore/ca-specific-schema.sql b/src/libstore/ca-specific-schema.sql
index c01dc5a76..4ca91f585 100644
--- a/src/libstore/ca-specific-schema.sql
+++ b/src/libstore/ca-specific-schema.sql
@@ -32,6 +32,8 @@ create table if not exists RealisationsRefs (
     foreign key (referrer) references Realisations(id) on delete cascade,
     foreign key (realisationReference) references Realisations(id) on delete restrict
 );
+-- used by deletion trigger
+create index if not exists IndexRealisationsRefsRealisationReference on RealisationsRefs(realisationReference);
 
 -- used by QueryRealisationReferences
 create index if not exists IndexRealisationsRefs on RealisationsRefs(referrer);
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 76524b01c..5cc5c91cc 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -152,6 +152,8 @@ void migrateCASchema(SQLite& db, Path schemaPath, AutoCloseFD& lockFd)
                     select id from Realisations where outputPath = old.id
                     );
                 end;
+                -- used by deletion trigger
+                create index if not exists IndexRealisationsRefsRealisationReference on RealisationsRefs(realisationReference);
             )");
             txn.commit();
         }