presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/SemiTransactionalHiveMetastore.java/PartitionAdder/rollback
class PartitionAdder:        public List<List<String>> rollback()
        {
            // drop created partitions
            List<List<String>> partitionsFailedToRollback = new ArrayList<>();
            for (List<String> createdPartitionValue : createdPartitionValues) {
                try {
                    metastore.dropPartition(identity, schemaName, tableName, createdPartitionValue, false);
                }
                catch (PartitionNotFoundException e) {
                    // Maybe some one deleted the partition we added.
                    // Anyways, we are good because the partition is not there anymore.
                }
                catch (Throwable t) {
                    partitionsFailedToRollback.add(createdPartitionValue);
                }
            }
            createdPartitionValues = partitionsFailedToRollback;
            return partitionsFailedToRollback;
        }