EITS: value "position" calculated incorrectly for CHAR(n) columns

create table ten(a int);

insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

create table t1(

  c_mktsegment char(10)

);

insert into t1 select 'AUTOMOBILE' from ten;

insert into t1 select 'FURNITURE' from ten;

insert into t1 select 'HOUSEHOLD' from ten;

insert into t1 select 'MACHINERY' from ten;

set histogram_size=20;

set use_stat_tables='preferably';

set optimizer_use_condition_selectivity=4;

analyze table t1 persistent for all;

explain extended select count(*) from t1 where c_mktsegment ='ABCD';

(gdb) print mp

  $334 = 4702394920804032544

(gdb) print minp

  $335 = 4707761685061911113

(gdb) print maxp

  $336 = 5566804592153216338

(gdb) print mp_prefix

  $337 = "    DCBA"

(gdb) print minp_prefix

  $338 = "IBOMOTUA"

(gdb) print maxp_prefix

  $339 = "RENIHCAM"

(gdb) p maxp > minp

  $340 = true

(gdb) p mp < minp

  $342 = true

  n= mp - minp;

(gdb) print n

  $343 = 1.8441377309451674e+19

(gdb) p ((double) mp) - ((double) minp)

  $344 = -5366764257878016