presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/file/FileHiveMetastore.java/FileHiveMetastore/commentTable
class FileHiveMetastore:    @Override
    public synchronized void commentTable(HiveIdentity identity, String databaseName, String tableName, Optional<String> comment)
    {
        alterTable(databaseName, tableName, oldTable -> {
            Map<String, String> parameters = oldTable.getParameters().entrySet().stream()
                    .filter(entry -> !entry.getKey().equals(TABLE_COMMENT))
                    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
            comment.ifPresent(value -> parameters.put(TABLE_COMMENT, value));

            return oldTable.withParameters(ImmutableMap.<String, String>builder()
                    .putAll(parameters)
                    .build());
        });
    }