mariadb/mysql-test/main/subselect_exists2in_costmat.test

#
# Tests of cost-based choice between the materialization and in-to-exists
# subquery execution strategies (MWL#89)
#
# The test file is divided into two groups of tests:
# A. Typical cases when either of the two strategies is selected:
#    1. Subquery in disjunctive WHERE clause of the outer query.
#    2. NOT IN subqueries
#    3. Subqueries with GROUP BY, HAVING, and aggregate functions
#    4. Subqueries in the SELECT and HAVING clauses
#    5. Subqueries with UNION
# B. Reasonably exhaustive tests of the various combinations of optimizer
#    switches, data distribution, available indexes, and typical queries.
#

set @subselect_mat_cost=@@optimizer_switch;
set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
#
# Test logging to slow log (there was some errors in the log files about
# the slow log when running under valgrind, so better to get this tested)
#
set long_query_time=0.1;


--disable_warnings
drop database if exists world;
--enable_warnings

set names utf8;

create database world;
use world;

--source include/world_schema.inc
--disable_query_log
--disable_result_log
--disable_warnings
--source include/world.inc
--enable_warnings
--enable_result_log
--enable_query_log

-- echo Make the schema and data more diverse by adding more indexes, nullable
-- echo columns, and NULL data.
create index SurfaceArea on Country(SurfaceArea);
create index Language on CountryLanguage(Language);
create index CityName on City(Name);
alter table City change population population int(11) null default 0;

--disable_cursor_protocol
--enable_prepare_warnings
select max(id) from City into @max_city_id;
--disable_prepare_warnings
--enable_cursor_protocol
insert into City values (@max_city_id + 1,'Kilifarevo','BGR',NULL);


SELECT COUNT(*) FROM Country;
SELECT COUNT(*) FROM City;
SELECT COUNT(*) FROM CountryLanguage;

set @@optimizer_switch = 'exists_to_in=on,in_to_exists=on,semijoin=on,materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on';

-- echo
-- echo 1. Subquery in a disjunctive WHERE clause of the outer query.
-- echo

-- echo
-- echo Q1.1m:
-- echo MATERIALIZATION: there are too many rows in the outer query
-- echo to be looked up in the inner table.
EXPLAIN
SELECT Name FROM Country
WHERE (EXISTS (select 1 from City where City.Population > 100000 and
Code = Country) OR
       Name LIKE 'L%') AND
      surfacearea > 1000000;

SELECT Name FROM Country
WHERE (EXISTS (select 1 from City where City.Population > 100000 and
Code = Country) OR
       Name LIKE 'L%') AND
      surfacearea > 1000000;

drop database world;

set optimizer_switch=@subselect_mat_cost;