This impacts the Grafana plugin.

From https://github.com/grafana/clickhouse-datasource/issues/198


    if an adhoc filter is specified for the field t1_distributed.f2
        the following query will be built by the plugin SELECT f1 from t1_distributed settings additional_table_filters = {'t1_distributed': 'f2 = xxx'}
        this query will actually not do its job of filtering
        i guess it is coming from the fact that additional_table_filters are applied by clickhouse when it reads the table....but distributed tables are not read.....
        if i replace in the built query, within the additional_table_filters settings, t1_distributed with t1_local (so a query like `SELECT f1 from t1_distributed settings additional_table_filters = {'t1_local': 'f2 = xxx'}), then it is working as expected
    i gave a try to add an adhoc filter on the "local" table (while my "main" query is still on the distributed table) (ie define an adhoc filter on the fied t1_local.f2)
        then the built query by the plugin does not include any additional_table_filters settings (i guess there is a check in order to add additional_table_filters only on the table used in the query)




const Cluster & cluster,
    const StorageID & remote_table_id,
    const ColumnsDescription & storage_columns,
    ContextPtr context)
{
    const auto & shards_info = cluster.getShardsInfo();
    auto query = "DESC TABLE " + remote_table_id.getFullTableName();
    auto new_context = ClusterProxy::updateSettingsForCluster(cluster, context, context->getSettingsRef());
    new_context->setSetting("describe_extend_object_types", true);
    
    Block sample_block
    {
        { ColumnString::create(), std::make_shared<DataTypeString>(), "name" },
        { ColumnString::create(), std::make_shared<DataTypeString>(), "type" },
    };
    auto execute_query_on_shard = [&](const auto & shard_info)
    {
        
        RemoteQueryExecutor executor(shard_info.pool, query, sample_block, new_context);
        executor.setPoolMode(PoolMode::GET_ONE);
        executor.setMainTable(remote_table_id);
        ColumnsDescription res;
        while (auto block = executor.read())