diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index d311d331c..15a903daf 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -693,6 +693,7 @@ struct AttrDb
     {
         SQLite db;
         SQLiteStmt insertAttribute;
+        SQLiteStmt insertPlaceholder;
         SQLiteStmt queryAttribute;
         SQLiteStmt queryAttributes;
         std::unique_ptr<SQLiteTxn> txn;
@@ -722,6 +723,9 @@ struct AttrDb
         state->insertAttribute.create(state->db,
             "insert or replace into Attributes(parent, name, type, value) values (?, ?, ?, ?)");
 
+        state->insertPlaceholder.create(state->db,
+            fmt("insert or ignore into Attributes(parent, name, type) values (?, ?, %d)", Placeholder));
+
         state->queryAttribute.create(state->db,
             "select rowid, type, value from Attributes where parent = ? and name = ?");
 
@@ -758,11 +762,9 @@ struct AttrDb
         assert(rowId);
 
         for (auto & attr : attrs)
-            state->insertAttribute.use()
+            state->insertPlaceholder.use()
                 (rowId)
-                (attr)
-                (AttrType::Placeholder)
-                (0, false).exec();
+                (attr).exec();
 
         return rowId;
     }