Assertion failure on hint-forced Split-Materialized plan

create table t1 (

  groups_20 int not null,

  groups_20_2 int not null,

  b int,

  primary key (groups_20, groups_20_2)

) engine=innodb;

insert into t1 select seq/1000, seq+1, seq from seq_1_to_20000;

create table t2 (a int, b int, index(a));

insert into t2 select seq, seq from seq_0_to_1000;

insert into t2 select seq, seq from seq_0_to_1000;

analyze table t1, t2;

analyze 

select /*+ SPLIT_MATERIALIZED(DT) */a, sum(b) 

from    

  (     

    select groups_20 from t1       

    group by groups_20       

    having count(*)  != 1000   

  ) DT    

  join 

  t2 on a = groups_20 

group by a;

sql/sql_select.cc:8283: double apply_selectivity_for_table(JOIN_TAB*, uint): Assertion `table_records == 0 || sel <=  s->table->opt_range_condition_rows / table_records' failed.

commit ef4be39bfcbae1b0090a3098e511d14457d6139f (HEAD -> main, origin/main)

Author: Mohammad El-Shennawy <mohamedwork216@gmail.com>

Date:   Fri Feb 27 10:28:59 2026 +0200

    MDEV-21543: Speed up VARCHAR pad space handling in multibyte collations (fix)

    Correct compilation on clang-20 by using a bitwise & rather than the

    incorrect &&.