**How to reproduce**
Clickhouse server 20.13.1.5273
```
CREATE TABLE default.test
(
`key` UInt32,
`ts` DateTime CODEC(DoubleDelta, LZ4),
`db_time` DateTime DEFAULT now() COMMENT 'spout-ignore' CODEC(DoubleDelta, LZ4)
)
ENGINE = MergeTree
PARTITION BY toStartOfTenMinutes(db_time)
ORDER BY (key, ts)
TTL db_time + toIntervalHour(3)
SETTINGS index_granularity = 8192, merge_with_ttl_timeout = 3600, min_rows_for_compact_part = 1000000, min_bytes_for_compact_part = 200000000, in_memory_parts_enable_wal = 0;


INSERT INTO test(key, ts) SELECT number % 1000, now() + intDiv(number,1000) FROM numbers(500);

SELECT * FROM test;
500 rows in set. Elapsed: 0.003 sec.

DETACH TABLE test;

ATTACH TABLE test;

SELECT * FROM test;

0 rows in set. Elapsed: 0.002 sec.
```

**Expected behavior**
Clickhouse would flush parts on disk.
if (!commands_for_size_validation.empty())
            {
                try
                {
                    auto fake_query_context = Context::createCopy(getContext());
                    fake_query_context->makeQueryContext();
                    fake_query_context->setCurrentQueryId("");
                    MutationsInterpreter interpreter(
                        shared_from_this(), metadata_snapshot, commands_for_size_validation, fake_query_context, false);
                    commands_size += interpreter.evaluateCommandsSize();
                }
                catch (...)
                {
                    tryLogCurrentException(log);
                    MergeTreeMutationEntry & entry = it->second;
                    entry.latest_fail_time = time(nullptr);
                    entry.latest_fail_reason = getCurrentExceptionMessage(false);
                    continue;
                }
            }
            if (current_ast_elements + commands_size >= max_ast_elements)
                break;
            current_ast_elements += commands_size;
            commands->insert(commands->end(), it->second.commands.begin(), it->second.commands.end());
        }
        if (!commands->empty())
        {
            bool is_partition_affected = false;
            for (const auto & command : *commands)
            {