presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/cache/CachingHiveMetastore.java/CachingHiveMetastore/grantRoles
class CachingHiveMetastore:    @Override
    public void grantRoles(Set<String> roles, Set<HivePrincipal> grantees, boolean withAdminOption, HivePrincipal grantor)
    {
        try {
            delegate.grantRoles(roles, grantees, withAdminOption, grantor);
        }
        finally {
            roleGrantsCache.invalidateAll();
        }
    }