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 Cluster::ShardInfo & shard_info,
    const StorageID & table_id,
    ContextPtr context,
    const ASTPtr & table_func_ptr)
{
    String query;
    if (table_func_ptr)
    {
        if (shard_info.isLocal())
        {
            TableFunctionPtr table_function_ptr = TableFunctionFactory::instance().get(table_func_ptr, context);
            return table_function_ptr->getActualTableStructure(context);
        }
        auto table_func_name = queryToString(table_func_ptr);
        query = "DESC TABLE " + table_func_name;
    }
    else
    {
        if (shard_info.isLocal())
        {
            auto storage_ptr = DatabaseCatalog::instance().getTable(table_id, context);