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

Some times there are not output from requests.
, parts_mover(this)
    , background_operations_assignee(*this, BackgroundJobsAssignee::Type::DataProcessing, getContext())
    , background_moves_assignee(*this, BackgroundJobsAssignee::Type::Moving, getContext())
    , use_metadata_cache(getSettings()->use_metadata_cache)
{
    context_->getGlobalContext()->initializeBackgroundExecutorsIfNeeded();
    const auto settings = getSettings();
    allow_nullable_key = attach || settings->allow_nullable_key;
    if (relative_data_path.empty())
        throw Exception("MergeTree storages require data path", ErrorCodes::INCORRECT_FILE_NAME);
    
    if (!attach)
        settings->sanityCheck(getContext()->getMergeMutateExecutor()->getMaxTasksCount());
    MergeTreeDataFormatVersion min_format_version(0);
    if (!date_column_name.empty())
    {
        try
        {
            checkPartitionKeyAndInitMinMax(metadata_.partition_key);
            setProperties(metadata_, metadata_, attach);
            if (minmax_idx_date_column_pos == -1)
                throw Exception("Could not find Date column", ErrorCodes::BAD_TYPE_OF_FIELD);
        }
        catch (Exception & e)
        {
            
            e.addMessage("(while initializing MergeTree partition key from date column " + backQuote(date_column_name) + ")");
            throw;
        }
    }