And waits for them. That's pointless.
#include <Common/typeid_cast.h>
#include <Common/escapeForFileName.h>
#include <Parsers/queryToString.h>
#include <cmath>
#include <ctime>
#include <numeric>
#include <boost/algorithm/string/replace.hpp>
namespace ProfileEvents
{
    extern const Event MergedRows;
    extern const Event MergedUncompressedBytes;
    extern const Event MergesTimeMilliseconds;
    extern const Event Merge;
}
namespace CurrentMetrics
{
    extern const Metric BackgroundPoolTask;
    extern const Metric PartMutation;
}
namespace DB
{
namespace ErrorCodes
{
    extern const int DIRECTORY_ALREADY_EXISTS;
    extern const int LOGICAL_ERROR;
    extern const int ABORTED;
}
static const double DISK_USAGE_COEFFICIENT_TO_SELECT = 2;
static const double DISK_USAGE_COEFFICIENT_TO_RESERVE = 1.1;
void FutureMergedMutatedPart::assign(MergeTreeData::DataPartsVector parts_)