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

Some times there are not output from requests.
{
    auto lock = lockParts();
    for (const auto & part : parts)
    {
        
        part->assertState({DataPartState::Deleting});
        modifyPartState(part, DataPartState::Outdated);
    }
}
void MergeTreeData::removePartsFinally(const MergeTreeData::DataPartsVector & parts)
{
    {
        auto lock = lockParts();
        
        for (const auto & part : parts)
        {
            
            if (part->getState() == DataPartState::Temporary)
                continue;
            auto it = data_parts_by_info.find(part->info);
            if (it == data_parts_by_info.end())
                throw Exception("Deleting data part " + part->name + " doesn't exist", ErrorCodes::LOGICAL_ERROR);