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|
--echo #
--echo # MDEV-30877: Output cardinality for derived table ignores GROUP BY
--echo #
--source include/have_sequence.inc
--source include/not_embedded.inc
create table t1 (
groups_20 int,
groups_20_2 int,
b int,
index (groups_20)
);
insert into t1 select seq/1000, seq/1000, seq from seq_1_to_20000;
create table t2 (a int, b int, index(a));
insert into t2 select seq, seq from seq_1_to_10;
analyze table t1 persistent for all;
set optimizer_trace=1;
--echo # Case 1: one indexed column
explain
select *
from
t2,
(select count(*) cnt, groups_20 from t1
group by groups_20) TBL
where
1;
--disable_view_protocol
select
json_detailed(json_extract(trace, '$**.materialized_output_cardinality'))
from
information_schema.optimizer_trace;
--enable_view_protocol
--echo # Case 2: one non- indexed column
explain
select *
from
t2,
(select count(*) cnt, groups_20_2 from t1
group by groups_20_2) TBL
where
1;
--disable_view_protocol
select
json_detailed(json_extract(trace, '$**.materialized_output_cardinality'))
from
information_schema.optimizer_trace;
--enable_view_protocol
--echo # Case 4: one indexed column, multiple tables
create table t3(c int);
insert into t3 select seq from seq_1_to_10;
explain
select *
from
t2,
(select count(*) cnt, groups_20 from t1,t3
group by groups_20) TBL;
--disable_view_protocol
select
json_detailed(json_extract(trace, '$**.materialized_output_cardinality'))
from
information_schema.optimizer_trace;
--enable_view_protocol
--echo # Case 5: group by two tables
explain
select *
from
t2,
(select count(*) cnt, groups_20 from t1,t3
group by groups_20, t3.c) TBL;
--disable_view_protocol
select
json_detailed(json_extract(trace, '$**.materialized_output_cardinality'))
from
information_schema.optimizer_trace;
--enable_view_protocol
--echo # Now, without an index
explain
select *
from
t2,
(select count(*) cnt, groups_20 from t1 use index(),t3 group by groups_20) TBL;
--disable_view_protocol
select
json_detailed(json_extract(trace, '$**.materialized_output_cardinality'))
from
information_schema.optimizer_trace;
--enable_view_protocol
set optimizer_trace=default;
drop table t1, t2, t3;
|
