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)




if (shard_info.isLocal())
        {
            const auto & res = getStructureOfRemoteTableInShard(cluster, shard_info, table_id, context, table_func_ptr);
            chassert(!res.empty());
            return res;
        }
    }
    for (const auto & shard_info : shards_info)
    {
        try
        {
            const auto & res = getStructureOfRemoteTableInShard(cluster, shard_info, table_id, context, table_func_ptr);
            
            
            if (res.empty())
                continue;
            return res;
        }
        catch (const NetException &)
        {
            std::string fail_message = getCurrentExceptionMessage(false);
            fail_messages += fail_message + '\n';
            continue;
        }
    }
    throw NetException(
        "All attempts to get table structure failed. Log: \n\n" + fail_messages + "\n",
        ErrorCodes::NO_REMOTE_SHARD_AVAILABLE);
}
ColumnsDescriptionByShardNum getExtendedObjectsOfRemoteTables(