I have a table with one million rows of data. And It's schema is like:
```
create table redis_dictionary_test
(
	date String,
	id String,
	value Int64
)
engine = MergeTree()
partition by date
order by id
settings index_granularity = 8192;
```

I also inserted one million key-value pairs into Redis.
The dictionary is like:
```
create dictionary redis_dict
(
	date String,
	id String,
	value Int64
)
PRIMARY KEY date, id
SOURCE(REDIS(
	host '127.0.0.1'
	port 6379
	storage_type 'hash_map'
	db_index 0
))
LAYOUT(COMPLEX_KEY_DIRECT())
```
When I execute this query: `SELECT COUNT(DISTINCT dictGet('redis_dict', 'value', tuple(date, id))) FROM redis_dictionary_test;`, ClickHouse seems stuck. Progress was in this state: 122.88 thousand rows, 5.84 MB (1.20 million rows/s., 56.83 MB/s.)  12% about five minutes. Finally, I canceled query.

I am sure Redis is fine. Because I monitored Redis and it could accept read and write commands.

I also executed this query on 1000, 10000 and 100000 rows of data. They can return data normally.

What happened to ClickHouse? Where can I find out the reason?
{
            if (bulk_string.isNull())
                throw Exception(ErrorCodes::TYPE_MISMATCH, "Type mismatch, expected not Null String");
            const String & string_value = bulk_string.value();
            switch (type)
            {
                case ValueType::vtUInt8:
                    insert<UInt8>(column, string_value);
                    break;
                case ValueType::vtUInt16:
                    insert<UInt16>(column, string_value);
                    break;
                case ValueType::vtUInt32:
                    insert<UInt32>(column, string_value);
                    break;
                case ValueType::vtUInt64:
                    insert<UInt64>(column, string_value);
                    break;
                case ValueType::vtInt8:
                    insert<Int8>(column, string_value);
                    break;
                case ValueType::vtInt16:
                    insert<Int16>(column, string_value);
                    break;
                case ValueType::vtInt32:
                    insert<Int32>(column, string_value);
                    break;
                case ValueType::vtInt64:
                    insert<Int64>(column, string_value);
                    break;