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mariadb/mysql-test/main/show_explain.test
Igor Babaev 658128af43 MDEV-16188 Use in-memory PK filters built from range index scans 
This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range  
conditions over indexes. In many cases usage of such filters reduce  
the number of disk seeks spent for fetching table rows.

In this implementation the choice of what possible filter to be applied  
(if any) is made purely on cost-based considerations.

This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.

Besides this patch contains a better implementation of the generic  
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.

This patch supports the feature for InnoDB and MyISAM.
2019-02-03 14:56:12 -08:00

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#
# Tests for SHOW EXPLAIN FOR functionality
#
--source include/have_debug.inc
--source include/have_innodb.inc
--disable_warnings
drop table if exists t0, t1, t2, t3, t4;
drop view if exists v1;
--enable_warnings
SET @old_debug= @@session.debug;
#
# Testcases in this file do not work with embedded server. The reason for this
# is that we use the following commands for synchronization:
#
# set @show_explain_probe_select_id=1;
# set debug_dbug='d,show_explain_probe_join_exec_start';
# send select count(*) from t1 where a < 100000;
#
# When ran with mysqltest_embedded, this translates into:
#
# Thread1> DBUG_PUSH("d,show_explain_probe_join_exec_start");
# Thread1> create another thread for doing "send ... reap"
# Thread2> mysql_parse("select count(*) from t1 where a < 100000");
#
# That is, "select count(*) ..." is ran in a thread for which DBUG_PUSH(...)
# has not been called. As a result, show_explain_probe_join_exec_start does not fire, and
# "select count(*) ..." does not wait till its SHOW EXPLAIN command, and the
# test fails.
#
-- source include/not_embedded.inc
set debug_sync='RESET';
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int);
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
alter table t1 add b int, add c int, add filler char(32);
update t1 set b=a, c=a, filler='fooo';
alter table t1 add key(a), add key(b);
#
# Try killing a non-existent thread
#
--error ER_NO_SUCH_THREAD
show explain for 2000000000;
--error ER_SET_CONSTANTS_ONLY
show explain for (select max(a) from t0);
#
# Setup two threads and their ids
#
let $thr1=`select connection_id()`;
connect (con1, localhost, root,,);
connection con1;
let $thr2=`select connection_id()`;
SET @old_debug= @@session.debug;
connection default;
# SHOW EXPLAIN FOR <idle thread>
--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
# SHOW EXPLAIN FOR <ourselves>
--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr1;
let $wait_condition= select State='show_explain_trap' from information_schema.processlist where id=$thr2;
#
# Test SHOW EXPLAIN for simple queries
#
connection con1;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select count(*) from t1 where a < 100000;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
send select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
--echo # We can catch EXPLAIN, too.
set @show_expl_tmp= @@optimizer_switch;
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
send explain select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set optimizer_switch= @show_expl_tmp;
set debug_dbug=@old_debug;
--echo # UNION, first branch
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # UNION, second branch
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send explain select a from t0 A union select a+1 from t0 B;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # Uncorrelated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 B) from t0 A where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # Uncorrelated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send explain select a, (select max(a) from t0 B) from t0 A where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # correlated subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # correlated subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # correlated subquery, select, while inside the subquery
set @show_explain_probe_select_id=2; # <---
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo # correlated subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
# TODO: explain in the parent subuqery when the un-correlated child has been
# run (and have done irreversible cleanups)
# ^^ Is this at all possible after 5.3?
# Maybe, for 5.3 try this:
# - run before/after the parent has invoked child's optimization
# - run after materialization
--echo # Try to do SHOW EXPLAIN for a query that runs a SET command:
--echo # I've found experimentally that select_id==2 here...
--echo #
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send set @foo= (select max(a) from t0 where sin(a) >0);
connection default;
--source include/wait_condition.inc
--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
evalp kill query $thr2;
connection con1;
--error ER_QUERY_INTERRUPTED
reap;
set debug_dbug=@old_debug;
--echo #
--echo # Attempt SHOW EXPLAIN for an UPDATE
--echo #
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
connection default;
--source include/wait_condition.inc
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
--source include/wait_condition.inc
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
set debug_dbug=@old_debug;
--echo #
--echo # Attempt SHOW EXPLAIN for a DELETE (UPD: now works)
--echo #
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
connection default;
--source include/wait_condition.inc
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
--source include/wait_condition.inc
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
set debug_dbug=@old_debug;
--echo #
--echo # Multiple SHOW EXPLAIN calls for one select
--echo #
create table t2 as select a as a, a as dummy from t0 limit 3;
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
drop table t2;
set debug_dbug=@old_debug;
--echo #
--echo # SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
--echo #
explain select * from t0 order by a;
set debug_dbug='+d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select * from t0 order by a;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # SHOW EXPLAIN for SELECT ... with "Using temporary"
--echo #
connection default;
explain select distinct a from t0;
connection con1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select distinct a from t0;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
--echo #
connection default;
explain select distinct a from t0;
connection con1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
send select distinct a from t0;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
--echo #
CREATE TABLE t2 ( a INT );
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
set debug_dbug='+d,show_explain_in_find_all_keys';
send SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
connection default;
--source include/wait_condition.inc
--echo # FIXED by "conservative assumptions about when QEP is available" fix:
--echo # NOTE: current code will not show "Using join buffer":
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t2;
--echo #
--echo # MDEV-239: Assertion `field_types == 0 ... ' failed in Protocol_text::store(double, uint32, String*) with
--echo # SHOW EXPLAIN over EXPLAIN EXTENDED
--echo #
CREATE TABLE t2 (a INT);
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t2;
--echo #
--echo # MDEV-240: SHOW EXPLAIN: Assertion `this->optimized == 2' failed in
--echo # JOIN::print_explain on query with a JOIN, TEMPTABLE view,
--echo #
CREATE TABLE t3 (a INT);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t3;
INSERT INTO t3 VALUES (8);
CREATE TABLE t2 (b INT);
INSERT INTO t2 VALUES (4),(5),(6),(7),(8),(9);
explain SELECT * FROM v1, t2;
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send SELECT * FROM v1, t2;
connection default;
--source include/wait_condition.inc
--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
evalp kill query $thr2;
connection con1;
--error ER_QUERY_INTERRUPTED
reap;
set debug_dbug=@old_debug;
DROP VIEW v1;
DROP TABLE t2, t3;
--echo #
--echo # MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
--echo #
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send select sleep(1);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # Same as above, but try another reason for JOIN to be degenerate
--echo #
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send select * from t0 where 1>10;
connection default;
--source include/wait_condition.inc
#--error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # Same as above, but try another reason for JOIN to be degenerate (2)
--echo #
create table t3(a int primary key);
insert into t3 select a from t0;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send select * from t0,t3 where t3.a=112233;
connection default;
--source include/wait_condition.inc
# --error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t3;
--echo #
--echo # MDEV-270: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with
--echo # select tables optimized away
--echo #
CREATE TABLE t2 (pk INT PRIMARY KEY, a INT ) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,4),(2,62),(3,7),(4,1),(5,0),(6,7),(7,7),(8,1),(9,7),(10,1),
(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5) ;
explain SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_do_select';
send SELECT * FROM t2 WHERE a =
(SELECT MAX(a) FROM t2
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t2;
--echo #
--echo # MDEV-273: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with impossible WHERE
--echo #
CREATE TABLE t2 (a1 INT, KEY(a1)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(4),(6),(7),(1),(0),(7),(7),(1),(7),(1),
(5),(2),(0),(1),(8),(1),(1),(9),(1),(5);
CREATE TABLE t3 (b1 INT) ENGINE=MyISAM;
INSERT INTO t3 VALUES
(4),(5),(8),(4),(8),(2),(9),(6),(4),(8),
(3),(5),(9),(6),(8),(3),(2),(6),(3),(1),
(4),(3),(1),(7),(0),(0),(9),(5),(9),(0),
(2),(2),(5),(9),(1),(4),(8),(6),(5),(5),
(1),(7),(2),(8),(9),(3),(2),(6),(6),(5),
(4),(3),(2),(7),(4),(6),(0),(8),(5),(8),
(2),(9),(7),(5),(7),(0),(4),(3),(1),(0),
(6),(2),(8),(3),(7),(3),(5),(5),(1),(2),
(1),(7),(1),(9),(9),(8),(3);
CREATE TABLE t4 (c1 INT) ENGINE=MyISAM;
EXPLAIN
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_do_select';
send
SELECT count(*) FROM t2, t3
WHERE a1 < ALL (
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t2, t3, t4;
--echo #
--echo # MDEV-275: SHOW EXPLAIN: server crashes in JOIN::print_explain with IN subquery and aggregate function
--echo #
CREATE TABLE t2 ( `pk` INT NOT NULL PRIMARY KEY, `a1` INT NOT NULL, KEY(`a1`)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),
(11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_end';
send
SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
connection default;
--source include/wait_condition.inc
# --error ER_TARGET_NOT_EXPLAINABLE
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t2;
DROP TABLE t1;
--echo #
--echo # MDEV-305: SHOW EXPLAIN: ref returned by SHOW EXPLAIN is different from the normal EXPLAIN ('const' vs empty string)
--echo #
CREATE TABLE t1(a INT, KEY(a));
INSERT INTO t1 VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send SELECT 'test' FROM t1 WHERE a=1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1;
--echo #
--echo # MDEV-299: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN changes back and forth during query execution
--echo #
create table t1 (key1 int, col1 int, col2 int, filler char(100), key(key1));
insert into t1 select A.a+ 10 * B.a, 10, 10, 'filler-data' from t0 A, t0 B;
# Make matches 3 records
update t1 set col1=3, col2=10 where key1=1; # small range
update t1 set col1=3, col2=1000 where key1=2; # big range
update t1 set col1=3, col2=10 where key1=3; # small range again
update t1 set col1=3, col2=1000 where key1=4; # big range
set @tmp_mdev299_jcl= @@join_cache_level;
set join_cache_level=0;
explain select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_test_if_quick_select';
send
select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t1;
--echo #
--echo # MDEV-297: SHOW EXPLAIN: Server gets stuck until timeout occurs while
--echo # executing SHOW INDEX and SHOW EXPLAIN in parallel
--echo #
CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send SHOW INDEX FROM t1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1;
--echo #
--echo # MDEV-324: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN for a query with TEMPTABLE view
--echo # loses 'DERIVED' line on the way without saying that the plan was already deleted
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
EXPLAIN SELECT a + 1 FROM v1;
set debug_dbug='+d,show_explain_probe_join_tab_preread';
set @show_explain_probe_select_id=1;
send
SELECT a + 1 FROM v1;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP VIEW v1;
DROP TABLE t1;
--echo #
--echo # MDEV-323: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN loses
--echo # 'UNION RESULT' line on the way without saying that the plan was already deleted
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (4),(6);
EXPLAIN
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
set debug_dbug='+d,show_explain_probe_union_read';
send
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1;
--echo #
--echo # MDEV-327: SHOW EXPLAIN: Different select_type in plans produced by SHOW EXPLAIN
--echo # and standard EXPLAIN: 'SUBQUERY' vs 'DEPENDENT SUBQUERY'
--echo #
CREATE TABLE t1 (a INT) ENGINE=Aria;
INSERT INTO t1 VALUES
(4),(6),(3),(5),(3),(246),(2),(9),(3),(8),
(1),(8),(8),(5),(7),(5),(1),(6),(2),(9);
CREATE TABLE t2 (b INT) ENGINE=Aria;
INSERT INTO t2 VALUES
(1),(7),(4),(7),(0),(2),(9),(4),(0),(9),
(1),(3),(8),(8),(18),(84),(6),(3),(6),(6);
EXPLAIN
SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
--send
SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1, t2;
--echo #
--echo # Test that SHOW EXPLAIN will print 'Distinct'.
--echo #
CREATE TABLE t1 (a int(10) unsigned not null primary key,b int(10) unsigned);
INSERT INTO t1 VALUES (1,1),(2,1),(3,1),(4,1);
CREATE TABLE t3 (a int(10) unsigned, key(A), b text);
INSERT INTO t3 VALUES (1,'1'),(2,'2');
create temporary table t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
explain select distinct t1.a from t1,t3 where t1.a=t3.a;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
--send
select distinct t1.a from t1,t3 where t1.a=t3.a;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t1,t3,t4;
--echo #
--echo # ---------- SHOW EXPLAIN and permissions -----------------
--echo #
create user test2@localhost;
grant ALL on test.* to test2@localhost;
# Give the user SUPER privilege so it can set debug_dbug variable.
grant super on *.* to test2@localhost;
connect (con2, localhost, test2,,);
connection con1;
--echo #
--echo # First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
--echo #
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
select * from t0 where a < 3;
connection default;
--source include/wait_condition.inc
connection con2;
--error ER_SPECIFIC_ACCESS_DENIED_ERROR
evalp show explain for $thr2;
connection default;
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
--echo #
--echo # Check that user test2 can do SHOW EXPLAIN on its own queries
--echo #
connect (con3, localhost, test2,,);
connection con2;
let $thr_con2=`select connection_id()`;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
select * from t0 where a < 3;
connection con1;
let $save_wait_condition= $wait_condition;
let $wait_condition= select State='show_explain_trap' from information_schema.processlist where id=$thr_con2;
--source include/wait_condition.inc
connection con3;
evalp show explain for $thr_con2;
connection con2;
reap;
connection con1;
disconnect con3;
let $wait_condition= $save_wait_condition;
--echo #
--echo # Now, grant test2 a PROCESSLIST permission, and see that he's able to observe us
--echo #
disconnect con2;
grant process on *.* to test2@localhost;
connect (con2, localhost, test2,,);
connection con1;
set debug_dbug=@old_debug;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
select * from t0 where a < 3;
connection default;
--source include/wait_condition.inc
connection con2;
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
revoke all privileges on test.* from test2@localhost;
drop user test2@localhost;
disconnect con2;
--echo #
--echo # Test that it is possible to KILL a SHOW EXPLAIN command that's waiting
--echo # on its target thread
--echo #
connect (con2, localhost, root,,);
connect (con3, localhost, root,,);
connection con2;
create table t1 (pk int primary key, data char(64)) engine=innodb;
insert into t1 select A.a + 10 * B.a + 100 * C.a, 'data1' from t0 A, t0 B, t0 C;
--echo # Lock two threads
set autocommit=0;
select * from t1 where pk between 10 and 20 for update;
connection con1;
set autocommit=0;
# This will freeze
send
select * from t1 where pk between 10 and 20 for update;
# run SHOW EXPLAIN on a frozen thread
connection default;
let $save_wait_condition= $wait_condition;
let $wait_condition= select State='Sending data' from information_schema.processlist where id=$thr2;
let $thr_default=`select connection_id()`;
--source include/wait_condition.inc
--echo # do: send_eval show explain for thr2;
--disable_query_log
send_eval show explain for $thr2;
--enable_query_log
# kill the SHOW EXPLAIN command
connection con3;
let $wait_condition= select State='show explain' from information_schema.processlist where id=$thr_default;
--source include/wait_condition.inc
evalp kill query $thr_default;
connection default;
--error ER_QUERY_INTERRUPTED
reap;
connection con2;
rollback;
connection con1;
reap;
drop table t1;
disconnect con3;
disconnect con2;
let $wait_condition= $save_wait_condition;
--echo #
--echo # Check that the I_S table is invisible
--echo #
select table_name from information_schema.tables where table_schema='information_schema' and table_name like '%explain%';
--echo #
--echo # MDEV-325: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN is different from standard EXPLAIN: type ALL vs 'index_merge'..
--echo #
CREATE TABLE t1 (a INT, b INT, KEY(a), KEY(b)) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(8,0),(128,5050),(5372,8),(234,7596),(2,0),(2907,8930),(1,0),
(0,5224),(8,7638),(960,5),(9872,1534),(0,2295),(3408,9809),
(7,0),(1168,0),(2089,5570),(0,205),(88,1018),(0,26528),
(0,0),(4,5567),(1444,145),(6,0),(1,7535),(7793,534),(70,9),
(178,1),(44,5),(189,0),(3,0);
EXPLAIN
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
--send
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_do_select';
--send
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t1;
--echo #
--echo # MDEV-298: SHOW EXPLAIN: Plan returned by SHOW EXPLAIN only contains
--echo # 'Using temporary' while the standard EXPLAIN says 'Using temporary; Using filesort'
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),
(10),(11),(12),(13),(14),(15),(16);
INSERT INTO t1 SELECT t11.a FROM t1 t11, t1 t12, t1 t13;
EXPLAIN SELECT a FROM t1 GROUP BY a;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
--send
SELECT a FROM t1 GROUP BY a;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t1;
--echo #
--echo # MDEV-408: SHOW EXPLAIN: Some values are chopped off in SHOW EXPLAIN output
--echo #
CREATE TABLE t1 (a INT, b VARCHAR(35)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (3989,'Abilene'),(3873,'Akron');
CREATE TABLE t2 (c INT, d VARCHAR(52) PRIMARY KEY, KEY(c)) ENGINE=InnoDB;
INSERT INTO t2 VALUES (86,'English'),(87,'Russian');
explain SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE d < b ) OR b < 's';
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
--send
SELECT SUM(a + SLEEP(0.1)) FROM t1 WHERE a IN ( SELECT c FROM t2 WHERE d < b ) OR b < 's';
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
drop table t1, t2;
--echo #
--echo # MDEV-412: SHOW EXPLAIN: Server crashes in JOIN::print_explain on a query with inner join and ORDER BY the same column twice
--echo #
CREATE TABLE t1 (a INT PRIMARY KEY, b VARCHAR(3), KEY(b)) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(3795,'USA'),(3913,'USA'),(3846,'ITA'),(4021,'USA'),(4005,'RUS'),(4038,'USA'),
(3825,'USA'),(3840,'USA'),(3987,'USA'),(3807,'USA'),(3896,'USA'),(4052,'USA'),
(3973,'USA'),(3982,'ITA'),(3965,'USA'),(3852,'RUS'),(4006,'USA'),(3800,'USA'),
(4020,'USA'),(4040,'USA'),(3916,'USA'),(3817,'USA'),(3885,'USA'),(3802,'USA'),
(4009,'ITA'),(3895,'USA'),(3963,'RUS'),(4045,'USA'),(3988,'USA'),(3815,'USA'),
(4063,'USA'),(3978,'USA'),(4019,'USA'),(3954,'USA'),(3950,'USA'),(3974,'ITA'),
(4054,'USA'),(4061,'RUS'),(3976,'USA'),(3966,'USA'),(3957,'USA'),(3981,'USA'),
(3923,'USA'),(3876,'USA'),(3819,'USA'),(3877,'USA'),(3829,'ITA'),(3964,'USA'),
(4053,'RUS'),(3917,'USA'),(3874,'USA'),(4023,'USA'),(4001,'USA'),(3872,'USA'),
(3890,'USA'),(3962,'USA'),(3886,'USA'),(4026,'ITA'),(3869,'USA'),(3937,'RUS'),
(3975,'USA'),(3944,'USA'),(3908,'USA'),(3867,'USA'),(3947,'USA'),(3838,'USA'),
(3796,'USA'),(3893,'USA'),(3920,'ITA'),(3994,'USA'),(3875,'RUS'),(4011,'USA'),
(4013,'USA'),(3810,'USA'),(3834,'USA'),(3968,'USA'),(3931,'USA'),(3839,'USA'),
(4042,'USA'),(4039,'ITA'),(3811,'USA'),(3837,'RUS'),(4041,'USA'),(3884,'USA'),
(3894,'USA'),(3879,'USA'),(3942,'USA'),(3959,'USA'),(3814,'USA'),(4044,'USA'),
(3971,'ITA'),(3823,'USA'),(3793,'RUS'),(3855,'USA'),(3905,'USA'),(3865,'USA'),
(4046,'USA'),(3990,'USA'),(4022,'USA'),(3833,'USA'),(3918,'USA'),(4064,'ITA'),
(3821,'USA'),(3836,'RUS'),(3921,'USA'),(3914,'USA'),(3888,'USA');
CREATE TABLE t2 (c VARCHAR(3) PRIMARY KEY) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('USA');
CREATE TABLE t3 (d VARCHAR(3), e VARCHAR(52), PRIMARY KEY (d,e)) ENGINE=MyISAM;
INSERT INTO t3 VALUES
('JPN','Japanese'),('KOR','Korean'),('POL','Polish'),('PRT','Portuguese'),
('ESP','Spanish'),('FRA','French'),('VNM','Vietnamese');
explain
SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_do_select';
send
SELECT b AS field1, b AS field2 FROM t1, t2, t3 WHERE d = b ORDER BY field1, field2;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1,t2,t3;
--echo #
--echo # MDEV-423: SHOW EXPLAIN: 'Using where' for a subquery is shown in EXPLAIN, but not in SHOW EXPLAIN output
--echo #
CREATE TABLE t1 (a INT) ENGINE=MyISAM;
INSERT INTO t1 VALUES (7),(0),(9),(3),(4),(2),(5),(7),(0),(9),(3),(4),(2),(5);
CREATE TABLE t2 (b INT, c INT) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(0,4),(8,6),(1,3),(8,5),(9,3),(24,246),(6,2),(1,9),(6,3),(2,8),
(4,1),(8,8),(4,8),(4,5),(7,7),(4,5),(1,1),(9,6),(4,2),(8,9);
create table t3 like t2;
insert into t3 select * from t2;
explain
SELECT max(a+b+c) FROM t1 AS alias1, ( SELECT * FROM t2 ) AS alias
WHERE EXISTS ( SELECT * FROM t3 WHERE b = c ) OR a <= 10;
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
SELECT max(a+b+c) FROM t1 AS alias1, ( SELECT * FROM t2 ) AS alias
WHERE EXISTS ( SELECT * FROM t3 WHERE b = c ) OR a <= 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1,t2,t3;
--echo #
--echo # MDEV-416: Server crashes in SQL_SELECT::cleanup on EXPLAIN with SUM ( DISTINCT ) in a non-correlated subquery (5.5-show-explain tree)
--echo #
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (b INT);
INSERT INTO t2 VALUES (8),(9);
EXPLAIN SELECT * FROM t1
WHERE ( 8, 89 ) IN ( SELECT b, SUM( DISTINCT b ) FROM t2 GROUP BY b );
DROP TABLE t1,t2;
--echo #
--echo # Check if queries in non-default charsets work.
--echo #
set names cp1251;
# The below are two Russian letters with codes E3FB in cp1251 encoding.
select charset('<27><>');
select hex('<27><>');
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
select * from t0 where length('<27><>') = a;
connection default;
set names utf8;
--source include/wait_condition.inc
evalp show explain for $thr2;
set names default;
connection con1;
# The constant should be two letters, the last looking like 'bl'
reap;
set debug_dbug=@old_debug;
set names default;
--echo #
--echo # MDEV-462: SHOW EXPLAIN: Assertion `table_list->table' fails in find_field_in_table_ref if FOR contains a non-numeric value
--echo #
--error ER_SET_CONSTANTS_ONLY
show explain for foo;
--echo #
--echo # MDEV-411: SHOW EXPLAIN: For dependent subquery EXPLAIN produces type=index, key, 'Using where; Using index',
--echo # while SHOW EXPLAIN says type=ALL, no key, 'Range checked for each record'
--echo #
CREATE TABLE t1 (a INT NOT NULL, KEY(a)) ENGINE=MyISAM;
INSERT INTO t1 VALUES (7),(0);
CREATE TABLE t2 (b INT NOT NULL) ENGINE=MyISAM;
INSERT INTO t2 VALUES (0),(8);
explain
SELECT SUM(b) FROM ( SELECT * FROM t1 ) AS alias1, t2
WHERE b <= ANY (
SELECT a FROM t1
WHERE a = b + SLEEP(0.2) OR a >= ( SELECT SUM(b) FROM t2 ));
set @show_explain_probe_select_id=1;
set debug_dbug='+d,show_explain_probe_join_exec_start';
send
SELECT SUM(b) FROM ( SELECT * FROM t1 ) AS alias1, t2
WHERE b <= ANY (
SELECT a FROM t1
WHERE a = b + SLEEP(0.2) OR a >= ( SELECT SUM(b) FROM t2 ));
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug=@old_debug;
DROP TABLE t1,t2;
drop table t0;
--echo #
--echo # MDEV-5148: Server crashes in print_explain on killing EXPLAIN EXTENDED
--echo #
create table t0 (a int not null);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int, b int);
insert into t1 select a,a from t0;
create table t2 as select * from t1;
set @show_explain_probe_select_id=2;
set debug_dbug='+d,show_explain_probe_best_ext_lim_search';
send
explain
select * from t0
where not exists ( select 1 from t1, t2 where t1.b=t2.b and t2.a=t0.a) and a is null;
connection default;
--source include/wait_condition.inc
evalp kill query $thr2;
connection con1;
--error ER_QUERY_INTERRUPTED
reap;
drop table t0,t1,t2;
--echo # End
connection default;
disconnect con1;
set debug_sync='RESET';
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