**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.
throw Exception(message, ErrorCodes::BAD_TTL_EXPRESSION);
            }
        }
    }
}
void MergeTreeData::checkStoragePolicy(const StoragePolicyPtr & new_storage_policy) const
{
    const auto old_storage_policy = getStoragePolicy();
    old_storage_policy->checkCompatibleWith(new_storage_policy);
}
void MergeTreeData::MergingParams::check(const StorageInMemoryMetadata & metadata) const
{
    const auto columns = metadata.getColumns().getAllPhysical();
    if (!sign_column.empty() && mode != MergingParams::Collapsing && mode != MergingParams::VersionedCollapsing)
        throw Exception("Sign column for MergeTree cannot be specified in modes except Collapsing or VersionedCollapsing.",
                        ErrorCodes::LOGICAL_ERROR);
    if (!version_column.empty() && mode != MergingParams::Replacing && mode != MergingParams::VersionedCollapsing)
        throw Exception("Version column for MergeTree cannot be specified in modes except Replacing or VersionedCollapsing.",
                        ErrorCodes::LOGICAL_ERROR);
    if (!columns_to_sum.empty() && mode != MergingParams::Summing)
        throw Exception("List of columns to sum for MergeTree cannot be specified in all modes except Summing.",
                        ErrorCodes::LOGICAL_ERROR);
    
    auto check_sign_column = [this, & columns](bool is_optional, const std::string & storage)
    {
        if (sign_column.empty())
        {
            if (is_optional)
                return;
            throw Exception("Logical error: Sign column for storage " + storage + " is empty", ErrorCodes::LOGICAL_ERROR);