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MDEV-32351: Significant slowdown with outer joins: Test coverage

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Make ANALYZE FORMAT=JSON print block-nl-join.r_unpack_ops when
analyze_print_r_unpack_ops debug flag is set.

Then, add a testcase.
This commit is contained in:
Sergei Petrunia
2023-10-26 20:44:10 +03:00
committed by Oleksandr Byelkin
parent 4ed5900626
commit 9bf2e5e3fe
3 changed files with 150 additions and 0 deletions
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44
mysql-test/main/join_cache_debug.test Normal file
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--source include/have_sequence.inc
--source include/have_debug.inc
--echo #
--echo # MDEV-32351: Significant slowdown for query with many outer joins
--echo #
CREATE TABLE t1 (b int NOT NULL, PRIMARY KEY (b)) ENGINE=MYISAM;
INSERT INTO t1 select seq from seq_1_to_10000;
CREATE TABLE t2 (b int NOT NULL, d varchar(255), KEY (b)) ENGINE=MYISAM ;
INSERT INTO t2 VALUES (1,1),(2,2),(3,3);
CREATE TABLE t3 (c int NOT NULL, PRIMARY KEY (c)) ENGINE=MYISAM ;
INSERT INTO t3 select seq from seq_1_to_3000;
CREATE TABLE t4 (c int NOT NULL, PRIMARY KEY (c)) ENGINE=MYISAM;
INSERT INTO t4 select seq from seq_1_to_3000;
ANALYZE TABLE t1,t2,t3,t4;
create table t1_t2 as
select
t1.b as t1_b, t2.b as t2_b, t2.d as t2_d
FROM t1
LEFT JOIN t2 ON t1.b = t2.b;
SET @old_debug=@@debug_dbug;
SET debug_dbug='+d,analyze_print_r_unpack_ops';
let $q= analyze
format=json
SELECT COUNT(*)
FROM t1_t2
LEFT JOIN t3 ON t2_d = t3.c
LEFT JOIN t4 ON t3.c=1;
echo $q;
let $js=`$q`;
--source include/analyze-format.inc
evalp select '$js' as JSON;
--echo # This must show 3000, not 30000000:
evalp select json_extract('$js', '\$**.r_unpack_ops') as R_UNPACK_OPS;
SET debug_dbug=@old_debug;
drop table t1,t2,t3,t4;
drop table t1_t2;