udb_query_preparation_area_t *prep_area,
const char *host, const char *plugin, const char *db_name,
char **column_names, size_t column_num, cdtime_t interval);
udb_query_preparation_area_t *prep_area,
const char *host, const char *plugin, const char *db_name,
char **column_names, size_t column_num, cdtime_t interval);