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

Some times there are not output from requests.
ContextPtr local_context, PartsTemporaryRename & renamed_parts)
{
    const String source_dir = "detached/";
    std::map<String, DiskPtr> name_to_disk;
    
    if (attach_part)
    {
        const String part_id = partition->as<ASTLiteral &>().value.safeGet<String>();
        validateDetachedPartName(part_id);
        auto disk = getDiskForDetachedPart(part_id);
        renamed_parts.addPart(part_id, "attaching_" + part_id, disk);
        if (MergeTreePartInfo::tryParsePartName(part_id, format_version))
            name_to_disk[part_id] = getDiskForDetachedPart(part_id);
    }
    else
    {
        String partition_id = getPartitionIDFromQuery(partition, local_context);
        LOG_DEBUG(log, "Looking for parts for partition {} in {}", partition_id, source_dir);
        ActiveDataPartSet active_parts(format_version);
        auto detached_parts = getDetachedParts();