```sql
CREATE TABLE t
(
   id Int64, 
   d String,
   p Map(String, String)
   
)
ENGINE = ReplacingMergeTree order by id settings index_granularity  = 0;


insert into t values (1,  's', {'a':'b'});

CH starts eating RAM until it crashes

the same with

insert into t select 1,  's', map('a','b');

```

{
    DataPartsVector total_covered_parts;
    if (!isEmpty())
    {
        auto settings = data.getSettings();
        auto parts_lock = acquired_parts_lock ? MergeTreeData::DataPartsLock() : data.lockParts();
        auto * owing_parts_lock = acquired_parts_lock ? acquired_parts_lock : &parts_lock;
        for (const auto & part : precommitted_parts)
            if (part->getDataPartStorage().hasActiveTransaction())
                part->getDataPartStorage().commitTransaction();
        if (txn)
            for (const auto & part : precommitted_parts)
            {
                DataPartPtr covering_part;
                DataPartsVector covered_active_parts = data.getActivePartsToReplace(part->info, part->name, covering_part, *owing_parts_lock);
                
                
                
                DataPartsVector covered_outdated_parts = data.getCoveredOutdatedParts(part, *owing_parts_lock);
                LOG_TEST(data.log, "Got {} oudated parts covered by {} (TID {} CSN {}): {}",
                         covered_outdated_parts.size(), part->getNameWithState(), txn->tid, txn->getSnapshot(), fmt::join(getPartsNames(covered_outdated_parts), ", "));
                data.filterVisibleDataParts(covered_outdated_parts, txn->getSnapshot(), txn->tid);
                DataPartsVector covered_parts;
                covered_parts.reserve(covered_active_parts.size() + covered_outdated_parts.size());
                std::move(covered_active_parts.begin(), covered_active_parts.end(), std::back_inserter(covered_parts));
                std::move(covered_outdated_parts.begin(), covered_outdated_parts.end(), std::back_inserter(covered_parts));
                MergeTreeTransaction::addNewPartAndRemoveCovered(data.shared_from_this(), part, covered_parts, txn);
            }
        MergeTreeData::WriteAheadLogPtr wal;