Statistics
https://play.clickhouse.com/play?user=play#c2VsZWN0IAp0b1N0YXJ0T2ZIb3VyKGNoZWNrX3N0YXJ0X3RpbWUpIGFzIGQsCmNvdW50KCksICBncm91cFVuaXFBcnJheShwdWxsX3JlcXVlc3RfbnVtYmVyKSwgIGFueShyZXBvcnRfdXJsKQpmcm9tIGNoZWNrcyB3aGVyZSAnMjAyMi0wNi0wMScgPD0gY2hlY2tfc3RhcnRfdGltZSBhbmQgdGVzdF9uYW1lIGxpa2UgJyUwMjQ5MV9wYXJ0X2xvZ19oYXNfdGFibGVfdXVpZCUnIGFuZCB0ZXN0X3N0YXR1cyBpbiAoJ0ZBSUwnLCAnRkxBS1knKSBncm91cCBieSBkIG9yZGVyIGJ5IGQgZGVzYw==

Some times there are not output from requests.
{
    MutationCommands commands = getFirstAlterMutationCommandsForPart(part);
    AlterConversions result{};
    for (const auto & command : commands)
        
        
        
        if (command.type == MutationCommand::Type::RENAME_COLUMN)
            result.rename_map[command.rename_to] = command.column_name;
    return result;
}
MergeTreeData::WriteAheadLogPtr MergeTreeData::getWriteAheadLog()
{
    std::lock_guard lock(write_ahead_log_mutex);
    if (!write_ahead_log)
    {
        auto reservation = reserveSpace(getSettings()->write_ahead_log_max_bytes);
        write_ahead_log = std::make_shared<MergeTreeWriteAheadLog>(*this, reservation->getDisk());
    }
    return write_ahead_log;
}
NamesAndTypesList MergeTreeData::getVirtuals() const