mariadb/mysql-test/r/bench_count_distinct.result
Varun Gupta 9419908f38 MDEV-15433: Optimizer does not use group by optimization with distinct
After the commit b76b69cd5f
loose index scan for queries with DISTINCT stopped working.
That is why that commit has to be reverted.
Additionally this patch  fixes the problem of MDEV-10880.
2018-08-05 13:25:40 +03:00

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drop table if exists t1;
create table t1(n int not null, key(n)) delay_key_write = 1;
select count(distinct n) from t1;
count(distinct n)
100
explain extended select count(distinct n) from t1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 range NULL n 4 NULL 10 100.00 Using index for group-by
Warnings:
Note 1003 select count(distinct `test`.`t1`.`n`) AS `count(distinct n)` from `test`.`t1`
drop table t1;