fix

Author: JingsongLi

paimon-python/pypaimon/write/table_upsert_by_key.py

@@ -169,20 +169,20 @@ def _upsert_partition(
         for i, key_tuple in enumerate(input_key_tuples):
             key_to_last_idx[key_tuple] = i  # last write wins
 
-        input_key_set = set(input_key_tuples)
-        if len(input_key_tuples) != len(input_key_set):
+        if len(input_key_tuples) != len(key_to_last_idx):
             original_count = len(input_key_tuples)
             dedup_indices = sorted(key_to_last_idx.values())
             partition_data = partition_data.take(dedup_indices)
             input_key_tuples = [input_key_tuples[i] for i in dedup_indices]
-            logger.info(
+            logger.warning(
                 "Deduplicated input from %d to %d rows in partition %s "
                 "(kept last occurrence).",
                 original_count, len(input_key_tuples), partition_spec,
             )
 
         # 3. Scan partition in batches, build key → _ROW_ID only for
         #    keys present in the input (avoids full-partition materialisation).
+        input_key_set = set(key_to_last_idx.keys())
         key_to_row_id = self._build_key_to_row_id_map(
             match_keys, partition_spec, input_key_set
         )