src/main/java/org/embulk/output/postgresql/AbstractPostgreSQLCopyBatchInsert.java in embulk-output-postgresql-0.8.3 vs src/main/java/org/embulk/output/postgresql/AbstractPostgreSQLCopyBatchInsert.java in embulk-output-postgresql-0.8.4

@@ -227,6 +227,13 @@
             return "";
         default:
             return String.valueOf(c);
         }
     }
+
+    @Override
+    public int[] getLastUpdateCounts()
+    {
+        // need not be implemented because AbstractPostgreSQLCopyBatchInsert won't retry.
+        return new int[]{};
+    }
 }