Hi Rich,

Could you please provide an example – CREATE TABLE and the plan that you see (or any other indications that you use to detect the sorted index scan)?

run mysqld with gdb and put a breakpoint at ha_partition::index_init
create table t (id bigint not null auto_increment primary key) partition by hash(id) partitions 2;
insert some rows into t.
select count(*) from t
the breakpoint hits and and the sorted parameter is true
ha_partition::index_init (this=0x7ffd81caa088, inx=0, sorted=true)
this causes the partition storage engine to sort the result set.
for tokudb 7.1.8-rc5, we think that this is a 2x slowdown.
in contrast, mysql 5.6 uses an unsorted indexing operation for this query.

Thanks, yes, I'm getting it this way also.
Leaving to psergei to decide if it's a bug and where it can/should be fixed, 10.0 in 'Fix Version' is tentative and can be changed both ways if necessary.