presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/metadata/DatabaseShardManager.java/DatabaseShardManager/minColumn
class DatabaseShardManager:    public static String minColumn(long columnId)
    {
        checkArgument(columnId >= 0, "invalid columnId %s", columnId);
        return format("c%s_min", columnId);
    }