Hello,

so I'm working to integrate CatBoost model with our ClickHouse cluster. It appears that, whenever we create a new XML model file in the configured path, the **first** call to the new model never returns (this is true both of the HTTP interface as well as via clickhouse-client).

Independently from whether the locked statement gets cancelled, subsequent calls succeed immediately.

```
16e8bdb5bbb9 :) select version();

SELECT version()

┌─version()─┐
│ 20.6.3.28 │
└───────────┘

1 rows in set. Elapsed: 0.006 sec.
```

Is this known behavior? If it helps, my models look like this:

```
<models>
    <model>
        <type>catboost</type>
        <name>ctr_predictor</name>
        <path>/catboost/my_predictor</path>
        <lifetime>0</lifetime>
    </model>
</models>
```
{
        std::lock_guard lock(mutex);
        readRepositories(repository_name, path);
        collectObjectConfigs();
        return object_configs;
    }
private:
    struct FileInfo
    {
        Poco::Timestamp last_update_time = 0;
        bool in_use = true; 
        Poco::AutoPtr<Poco::Util::AbstractConfiguration> file_contents; 
        std::unordered_map<String , String > objects;
    };
    struct RepositoryInfo
    {
        std::unique_ptr<Repository> repository;
        std::unordered_map<String , FileInfo> files;
    };
    
    
    void readRepositories(const std::optional<String> & only_repository_name = {}, const std::optional<String> & only_path = {})