From 620d520d680fc8849a518d0fe5172bcedb632564 Mon Sep 17 00:00:00 2001
From: Daniel Black <daniel@mariadb.org>
Date: Thu, 29 Sep 2022 00:20:23 +1000
Subject: [PATCH 1/6] MDEV-29614 mariadb-upgrade calls mysql and mysql-check
 (#2279)

rather than mariadb/mariadb-check
---
 client/mysql_upgrade.c               |  6 +++---
 mysql-test/main/mysql_upgrade.result |  6 +++---
 mysql-test/main/mysql_upgrade.test   | 12 ++++++------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/client/mysql_upgrade.c b/client/mysql_upgrade.c
index 4e7ddec312f90..ad54b06101ebf 100644
--- a/client/mysql_upgrade.c
+++ b/client/mysql_upgrade.c
@@ -935,7 +935,7 @@ static int run_mysqlcheck_upgrade(my_bool mysql_db_only)
     return 0;
   }
   verbose("Phase %d/%d: Checking and upgrading %s", ++phase, phases_total, what);
-  print_conn_args("mysqlcheck");
+  print_conn_args("mariadb-check");
   retch= run_tool(mysqlcheck_path,
                   NULL, /* Send output from mysqlcheck directly to screen */
                   defaults_file,
@@ -1451,7 +1451,7 @@ int main(int argc, char **argv)
   }
 
   /* Find mysql */
-  find_tool(mysql_path, IF_WIN("mysql.exe", "mysql"), self_name);
+  find_tool(mysql_path, IF_WIN("mariadb.exe", "mariadb"), self_name);
 
   open_mysql_upgrade_file();
 
@@ -1459,7 +1459,7 @@ int main(int argc, char **argv)
     exit(upgrade_already_done(0) == 0);
 
   /* Find mysqlcheck */
-  find_tool(mysqlcheck_path, IF_WIN("mysqlcheck.exe", "mysqlcheck"), self_name);
+  find_tool(mysqlcheck_path, IF_WIN("mariadb-check.exe", "mariadb-check"), self_name);
 
   if (opt_systables_only && !opt_silent)
     printf("The --upgrade-system-tables option was used, user tables won't be touched.\n");
diff --git a/mysql-test/main/mysql_upgrade.result b/mysql-test/main/mysql_upgrade.result
index f1872c17802af..e2155b522a30e 100644
--- a/mysql-test/main/mysql_upgrade.result
+++ b/mysql-test/main/mysql_upgrade.result
@@ -778,18 +778,18 @@ FLUSH PRIVILEGES;
 #
 This installation of MariaDB is already upgraded to MariaDB .
 There is no need to run mysql_upgrade again for MariaDB .
-Looking for 'mysql' as: mysql
+Looking for 'mariadb' as: mariadb
 This installation of MariaDB is already upgraded to MariaDB .
 There is no need to run mysql_upgrade again for MariaDB .
 #
 # MDEV-27279: mariadb_upgrade check-if-upgrade absence is do it
 #
-Looking for 'mysql' as: mysql
+Looking for 'mariadb' as: mariadb
 Empty or non existent ...mysql_upgrade_info. Assuming mysql_upgrade has to be run!
 #
 # MDEV-27279: mariadb_upgrade check-if-upgrade with minor version change
 #
-Looking for 'mysql' as: mysql
+Looking for 'mariadb' as: mariadb
 This installation of MariaDB is already upgraded to MariaDB .
 There is no need to run mysql_upgrade again for MariaDB .
 This installation of MariaDB is already upgraded to MariaDB .
diff --git a/mysql-test/main/mysql_upgrade.test b/mysql-test/main/mysql_upgrade.test
index 017a7cc742fce..19d490d73bd09 100644
--- a/mysql-test/main/mysql_upgrade.test
+++ b/mysql-test/main/mysql_upgrade.test
@@ -55,7 +55,7 @@ DROP USER mysqltest1@'%';
 
 --echo Run mysql_upgrade with a non existing server socket
 --replace_result $MYSQLTEST_VARDIR var
---replace_regex /.*mysqlcheck.*: Got/mysqlcheck: Got/ /\([0-9|-]*\)/(errno)/
+--replace_regex /.*mariadb-check.*: Got/mariadb-check: Got/ /\([0-9|-]*\)/(errno)/
 --error 1
 # NC: Added --skip-version-check, as the version check would fail when
 # mysql_upgrade tries to get the server version.
@@ -139,7 +139,7 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 --echo Run mysql_upgrade with unauthorized access
 --error 1
 --exec $MYSQL_UPGRADE --skip-verbose --user=root --password=wrong_password 2>&1
---replace_regex /.*mysqlcheck.*: Got/mysqlcheck: Got/ /\([0-9|-]*\)/(errno)/
+--replace_regex /.*mariadb-check.*: Got/mariadb-check: Got/ /\([0-9|-]*\)/(errno)/
 --error 1
 --exec $MYSQL_UPGRADE --skip-verbose --skip-version-check --user=root --password=wrong_password 2>&1
 
@@ -290,7 +290,7 @@ FLUSH PRIVILEGES;
 --replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
 --error 1
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
---replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mariadb.* as:[^\n]*/'mariadb' as: mariadb/
 --error 1
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
 
@@ -302,7 +302,7 @@ FLUSH PRIVILEGES;
 --replace_regex /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
 
---replace_regex /'mysql.* as:[^\n]*/'mysql' as: mysql/ /open .* Assuming/open XXX. Assuming/ /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
+--replace_regex /'mariadb.* as:[^\n]*/'mariadb' as: mariadb/ /open .* Assuming/open XXX. Assuming/ /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
 
 --echo #
@@ -324,7 +324,7 @@ EOF
 
 --error 1
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --silent
---replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mariadb.* as:[^\n]*/'mariadb' as: mariadb/
 --error 1
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
 --replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
@@ -351,7 +351,7 @@ EOF
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --silent
 --replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
---replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mariadb.* as:[^\n]*/'mysql' as: mysql/
 --exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
 --remove_file $MYSQLD_DATADIR/mysql_upgrade_info
 drop table mysql.global_priv;

From d7d3ad698abde16978e094b825e17a6ecd8604e8 Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Wed, 28 Sep 2022 13:00:38 +0200
Subject: [PATCH 2/6] debug_sync: ignore "sort" kills and disconnects

only "hard" kills will now interrupt debug_sync waits.
this is needed to have debug_sync points that work during disconnect
---
 sql/debug_sync.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sql/debug_sync.cc b/sql/debug_sync.cc
index 09aa069512730..b5de53be0000e 100644
--- a/sql/debug_sync.cc
+++ b/sql/debug_sync.cc
@@ -1467,7 +1467,7 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
         the required dynamic memory allocated.
       */
       while (stringcmp(&debug_sync_global.ds_signal, &action->wait_for) &&
-             !thd->killed && opt_debug_sync_timeout)
+             !(thd->killed & KILL_HARD_BIT) && opt_debug_sync_timeout)
       {
         error= mysql_cond_timedwait(&debug_sync_global.ds_cond,
                                     &debug_sync_global.ds_mutex,

From 74ac683a7e822f3287e75527d7d3a7ff1256c46c Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Wed, 28 Sep 2022 14:43:30 +0200
Subject: [PATCH 3/6] cleanup: kill test

split it into debug and non-debug tests
---
 mysql-test/main/kill.result       | 227 +----------------------
 mysql-test/main/kill.test         | 296 +----------------------------
 mysql-test/main/kill_debug.result | 223 ++++++++++++++++++++++
 mysql-test/main/kill_debug.test   | 298 ++++++++++++++++++++++++++++++
 4 files changed, 529 insertions(+), 515 deletions(-)
 create mode 100644 mysql-test/main/kill_debug.result
 create mode 100644 mysql-test/main/kill_debug.test

diff --git a/mysql-test/main/kill.result b/mysql-test/main/kill.result
index 5d38bd900596a..797052710e86c 100644
--- a/mysql-test/main/kill.result
+++ b/mysql-test/main/kill.result
@@ -1,225 +1,7 @@
 set local sql_mode="";
 set global sql_mode="";
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE IF EXISTS t1, t2, t3;
-DROP FUNCTION IF EXISTS MY_KILL;
-CREATE FUNCTION MY_KILL(tid INT) RETURNS INT
-BEGIN
-DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN END;
-KILL tid;
-RETURN (SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = tid);
-END|
-connect  con1, localhost, root,,;
-connect  con2, localhost, root,,;
-connection con1;
-connection con2;
-connection con1;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read';
-connection con2;
-SET DEBUG_SYNC='now WAIT_FOR con1_read';
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-SET DEBUG_SYNC = 'RESET';
-connection con1;
-SELECT 1;
-Got one of the listed errors
-SELECT 1;
-1
-1
-SELECT @id != CONNECTION_ID();
-@id != CONNECTION_ID()
-1
-connection con2;
-SELECT 4;
-4
-4
-connection default;
-KILL (SELECT COUNT(*) FROM mysql.user);
-ERROR 42000: KILL does not support subqueries or stored functions
-connection con1;
-connection con2;
-connection con1;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read WAIT_FOR kill';
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_read';
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-SET DEBUG_SYNC = 'RESET';
-connection con1;
-SELECT 1;
-Got one of the listed errors
-SELECT 1;
-1
-1
-SELECT @id != CONNECTION_ID();
-@id != CONNECTION_ID()
-1
-connection con2;
-SELECT 4;
-4
-4
-connection default;
-CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT);
-CREATE TABLE t2 (id INT UNSIGNED NOT NULL);
-INSERT INTO t1 VALUES
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0);
-INSERT t1 SELECT 0 FROM t1 AS a1, t1 AS a2 LIMIT 4032;
-INSERT INTO t2 SELECT id FROM t1;
-connection con1;
-connection con2;
-connection con1;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync';
-SELECT id FROM t1 WHERE id IN
-(SELECT DISTINCT a.id FROM t2 a, t2 b, t2 c, t2 d
-GROUP BY ACOS(1/a.id), b.id, c.id, d.id
-HAVING a.id BETWEEN 10 AND 20);
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL @id;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-connection con1;
-Got one of the listed errors
-SELECT 1;
-1
-1
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE t1, t2;
-connection con1;
-connection con2;
-connection con1;
-SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync WAIT_FOR kill';
-SELECT ACOS(0);
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ACOS(0)
-1.5707963267948966
-SELECT 1;
-1
-1
-SELECT @id = CONNECTION_ID();
-@id = CONNECTION_ID()
-1
-connection default;
-SET DEBUG_SYNC = 'RESET';
-CREATE TABLE t1 (f1 INT);
-CREATE FUNCTION bug27563() RETURNS INT(11)
-DETERMINISTIC
-BEGIN
-DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
-DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
-SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
-RETURN 1;
-END|
-connection con1;
-connection con2;
-connection con1;
-INSERT INTO t1 VALUES (bug27563());
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ERROR 70100: Query execution was interrupted
-SELECT * FROM t1;
-f1
-connection default;
-SET DEBUG_SYNC = 'RESET';
-INSERT INTO t1 VALUES(0);
-connection con1;
-UPDATE t1 SET f1= bug27563();
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ERROR 70100: Query execution was interrupted
-SELECT * FROM t1;
-f1
-0
-connection default;
-SET DEBUG_SYNC = 'RESET';
-INSERT INTO t1 VALUES(1);
-connection con1;
-DELETE FROM t1 WHERE bug27563() IS NULL;
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ERROR 70100: Query execution was interrupted
-SELECT * FROM t1;
-f1
-0
-1
-connection default;
-SET DEBUG_SYNC = 'RESET';
-connection con1;
-SELECT * FROM t1 WHERE f1= bug27563();
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ERROR 70100: Query execution was interrupted
-SELECT * FROM t1;
-f1
-0
-1
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP FUNCTION bug27563;
-CREATE TABLE t2 (f2 INT);
-CREATE TRIGGER trg27563 BEFORE INSERT ON t1 FOR EACH ROW
-BEGIN
-DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
-DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
-INSERT INTO t2 VALUES(0);
-SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
-INSERT INTO t2 VALUES(1);
-END|
-connection con1;
-INSERT INTO t1 VALUES(2),(3);
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-ERROR 70100: Query execution was interrupted
-SELECT * FROM t1;
-f1
-0
-1
-SELECT * FROM t2;
-f2
-0
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE t1, t2;
-#
-# Bug#19723: kill of active connection yields different error code
-# depending on platform.
-#
-connection con1;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-KILL @id;
-ERROR 70100: Connection was killed
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-connection con1;
-# ER_SERVER_SHUTDOWN, CR_SERVER_GONE_ERROR, CR_SERVER_LOST,
-# depending on the timing of close of the connection socket
-SELECT 1;
-Got one of the listed errors
-SELECT 1;
-1
-1
-SELECT @id != CONNECTION_ID();
-@id != CONNECTION_ID()
-1
-connection default;
-SET DEBUG_SYNC = 'RESET';
+connect con1, localhost, root;
+connect con2, localhost, root;
 #
 # Additional test for WL#3726 "DDL locking for all metadata objects"
 # Check that DDL and DML statements waiting for metadata locks can
@@ -227,7 +9,6 @@ SET DEBUG_SYNC = 'RESET';
 # can be tricky to write test case for some of them (e.g. REPAIR or
 # ALTER and other statements under LOCK TABLES).
 #
-drop tables if exists t1, t2, t3;
 create table t1 (i int primary key);
 connect  blocker, localhost, root, , ;
 connect  dml, localhost, root, , ;
@@ -380,9 +161,9 @@ connection default;
 ERROR 70100: Query execution was interrupted
 disconnect con5;
 DROP USER u1@localhost;
-SET DEBUG_SYNC = 'RESET';
-DROP FUNCTION MY_KILL;
 set global sql_mode=default;
+disconnect con1;
+disconnect con2;
 #
 # MDEV-17998
 # Deadlock and eventual Assertion `!table->pos_in_locked_tables' failed
diff --git a/mysql-test/main/kill.test b/mysql-test/main/kill.test
index 7dc5715882557..e40918ee6b2a8 100644
--- a/mysql-test/main/kill.test
+++ b/mysql-test/main/kill.test
@@ -8,294 +8,11 @@
 #
 
 -- source include/not_embedded.inc
--- source include/have_debug_sync.inc
 set local sql_mode="";
 set global sql_mode="";
 
---disable_warnings
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE IF EXISTS t1, t2, t3;
-DROP FUNCTION IF EXISTS MY_KILL;
---enable_warnings
-
-delimiter |;
-# Helper function used to repeatedly kill a session.
-CREATE FUNCTION MY_KILL(tid INT) RETURNS INT
-BEGIN
-  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN END;
-  KILL tid;
-  RETURN (SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = tid);
-END|
-delimiter ;|
-
-connect (con1, localhost, root,,);
-connect (con2, localhost, root,,);
-
-# Save id of con1
-connection con1;
---disable_reconnect
-let $ID= `SELECT @id := CONNECTION_ID()`;
-connection con2;
-let $ignore= `SELECT @id := $ID`;
-connection con1;
-# Signal when this connection is terminating.
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-# See if we can kill read().
-# Run into read() immediately after hitting 'before_do_command_net_read'.
-SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read';
-
-# Kill con1
-connection con2;
-SET DEBUG_SYNC='now WAIT_FOR con1_read';
-# At this point we have no way to figure out, when con1 is blocked in
-# reading from the socket. Sending KILL to early would not terminate
-# con1. So we repeat KILL until con1 terminates.
-let $wait_condition= SELECT MY_KILL(@id);
---source include/wait_condition.inc
-# If KILL missed the read(), sync point wait will time out.
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-SET DEBUG_SYNC = 'RESET';
-
-connection con1;
---error 1053,2006,2013,5014
-SELECT 1;
-
---enable_reconnect
-# this should work, and we should have a new connection_id()
-SELECT 1;
-let $ignore= `SELECT @id := $ID`;
-SELECT @id != CONNECTION_ID();
-
-#make sure the server is still alive
-connection con2;
-SELECT 4;
-connection default;
-
---error ER_SUBQUERIES_NOT_SUPPORTED
-KILL (SELECT COUNT(*) FROM mysql.user);
-
-connection con1;
-let $ID= `SELECT @id := CONNECTION_ID()`;
-connection con2;
-let $ignore= `SELECT @id := $ID`;
-connection con1;
-disable_reconnect;
-# Signal when this connection is terminating.
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-# See if we can kill the sync point itself.
-# Wait in 'before_do_command_net_read' until killed.
-# It doesn't wait for a signal 'kill' but for to be killed.
-# The signal name doesn't matter here.
-SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read WAIT_FOR kill';
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_read';
-# Repeat KILL until con1 terminates.
-let $wait_condition= SELECT MY_KILL(@id);
---source include/wait_condition.inc
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-SET DEBUG_SYNC = 'RESET';
-
-connection con1;
---error 1053,2006,2013,5014
-SELECT 1;
-enable_reconnect;
-SELECT 1;
-let $ignore= `SELECT @id := $ID`;
-SELECT @id != CONNECTION_ID();
-connection con2;
-SELECT 4;
-connection default;
-
-#
-# BUG#14851: killing long running subquery processed via a temporary table.
-#
-
-CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT);
-CREATE TABLE t2 (id INT UNSIGNED NOT NULL);
-
-INSERT INTO t1 VALUES
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
-(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0);
-INSERT t1 SELECT 0 FROM t1 AS a1, t1 AS a2 LIMIT 4032;
-
-INSERT INTO t2 SELECT id FROM t1;
-
-connection con1;
-let $ID= `SELECT @id := CONNECTION_ID()`;
-connection con2;
-let $ignore= `SELECT @id := $ID`;
-
-connection con1;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
-SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync';
-# This is a very long running query. If this test start failing,
-# it may be necessary to change to an even longer query.
-send SELECT id FROM t1 WHERE id IN
-       (SELECT DISTINCT a.id FROM t2 a, t2 b, t2 c, t2 d
-          GROUP BY ACOS(1/a.id), b.id, c.id, d.id
-          HAVING a.id BETWEEN 10 AND 20);
-
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL @id;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-
-connection con1;
---error 1317,1053,2006,2013,5014
-reap;
-SELECT 1;
-
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE t1, t2;
-
-#
-# Test of blocking of sending ERROR after OK or EOF
-#
-connection con1;
-let $ID= `SELECT @id := CONNECTION_ID()`;
-connection con2;
-let $ignore= `SELECT @id := $ID`;
-connection con1;
-SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync WAIT_FOR kill';
-send SELECT ACOS(0);
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
-reap;
-SELECT 1;
-SELECT @id = CONNECTION_ID();
-connection default;
-SET DEBUG_SYNC = 'RESET';
-
-#
-# Bug#27563: Stored functions and triggers wasn't throwing an error when killed.
-#
-CREATE TABLE t1 (f1 INT);
-delimiter |;
-CREATE FUNCTION bug27563() RETURNS INT(11)
-DETERMINISTIC
-BEGIN
-  DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
-  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
-  SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
-  RETURN 1;
-END|
-delimiter ;|
-# Test stored functions
-# Test INSERT
-connection con1;
-let $ID= `SELECT @id := CONNECTION_ID()`;
-connection con2;
-let $ignore= `SELECT @id := $ID`;
-connection con1;
-send INSERT INTO t1 VALUES (bug27563());
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
---error 1317
-reap;
-SELECT * FROM t1;
-connection default;
-SET DEBUG_SYNC = 'RESET';
-
-# Test UPDATE
-INSERT INTO t1 VALUES(0);
-connection con1;
-send UPDATE t1 SET f1= bug27563();
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
---error 1317
-reap;
-SELECT * FROM t1;
-connection default;
-SET DEBUG_SYNC = 'RESET';
-
-# Test DELETE
-INSERT INTO t1 VALUES(1);
-connection con1;
-send DELETE FROM t1 WHERE bug27563() IS NULL;
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
---error 1317
-reap;
-SELECT * FROM t1;
-connection default;
-SET DEBUG_SYNC = 'RESET';
-
-# Test SELECT
-connection con1;
-send SELECT * FROM t1 WHERE f1= bug27563();
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
---error 1317
-reap;
-SELECT * FROM t1;
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP FUNCTION bug27563;
-
-# Test TRIGGERS
-CREATE TABLE t2 (f2 INT);
-delimiter |;
-CREATE TRIGGER trg27563 BEFORE INSERT ON t1 FOR EACH ROW
-BEGIN
-  DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
-  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
-  INSERT INTO t2 VALUES(0);
-  SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
-  INSERT INTO t2 VALUES(1);
-END|
-delimiter ;|
-connection con1;
-send INSERT INTO t1 VALUES(2),(3);
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
-KILL QUERY @id;
-connection con1;
---error 1317
-reap;
-SELECT * FROM t1;
-SELECT * FROM t2;
-connection default;
-SET DEBUG_SYNC = 'RESET';
-DROP TABLE t1, t2;
-
---echo #
---echo # Bug#19723: kill of active connection yields different error code
---echo # depending on platform.
---echo #
-
---connection con1
-let $ID= `SELECT @id := CONNECTION_ID()`;
-SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
---disable_reconnect
---error ER_CONNECTION_KILLED
-KILL @id;
-
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
-connection con1;
---echo # ER_SERVER_SHUTDOWN, CR_SERVER_GONE_ERROR, CR_SERVER_LOST,
---echo # depending on the timing of close of the connection socket
---error 1053,2006,2013,5014
-SELECT 1;
---enable_reconnect
-SELECT 1;
-let $ignore= `SELECT @id := $ID`;
-SELECT @id != CONNECTION_ID();
-connection default;
-SET DEBUG_SYNC = 'RESET';
+connect con1, localhost, root;
+connect con2, localhost, root;
 
 --echo #
 --echo # Additional test for WL#3726 "DDL locking for all metadata objects"
@@ -304,9 +21,6 @@ SET DEBUG_SYNC = 'RESET';
 --echo # can be tricky to write test case for some of them (e.g. REPAIR or
 --echo # ALTER and other statements under LOCK TABLES).
 --echo #
---disable_warnings
-drop tables if exists t1, t2, t3;
---enable_warnings
 
 create table t1 (i int primary key);
 connect (blocker, localhost, root, , );
@@ -570,11 +284,9 @@ reap;
 disconnect con5;
 DROP USER u1@localhost;
 
-
-SET DEBUG_SYNC = 'RESET';
-DROP FUNCTION MY_KILL;
-
 set global sql_mode=default;
+disconnect con1;
+disconnect con2;
 
 --echo #
 --echo # MDEV-17998
diff --git a/mysql-test/main/kill_debug.result b/mysql-test/main/kill_debug.result
new file mode 100644
index 0000000000000..d0fadb5c7b5a3
--- /dev/null
+++ b/mysql-test/main/kill_debug.result
@@ -0,0 +1,223 @@
+set local sql_mode="";
+set global sql_mode="";
+CREATE FUNCTION MY_KILL(tid INT) RETURNS INT
+BEGIN
+DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN END;
+KILL tid;
+RETURN (SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = tid);
+END|
+connect con1, localhost, root;
+connect con2, localhost, root;
+connection con1;
+connection con2;
+connection con1;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read';
+connection con2;
+SET DEBUG_SYNC='now WAIT_FOR con1_read';
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+SET DEBUG_SYNC = 'RESET';
+connection con1;
+SELECT 1;
+Got one of the listed errors
+SELECT 1;
+1
+1
+SELECT @id != CONNECTION_ID();
+@id != CONNECTION_ID()
+1
+connection con2;
+SELECT 4;
+4
+4
+connection default;
+KILL (SELECT COUNT(*) FROM mysql.user);
+ERROR 42000: KILL does not support subqueries or stored functions
+connection con1;
+connection con2;
+connection con1;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read WAIT_FOR kill';
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_read';
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+SET DEBUG_SYNC = 'RESET';
+connection con1;
+SELECT 1;
+Got one of the listed errors
+SELECT 1;
+1
+1
+SELECT @id != CONNECTION_ID();
+@id != CONNECTION_ID()
+1
+connection con2;
+SELECT 4;
+4
+4
+connection default;
+CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT);
+CREATE TABLE t2 (id INT UNSIGNED NOT NULL);
+INSERT INTO t1 VALUES
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0);
+INSERT t1 SELECT 0 FROM t1 AS a1, t1 AS a2 LIMIT 4032;
+INSERT INTO t2 SELECT id FROM t1;
+connection con1;
+connection con2;
+connection con1;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync';
+SELECT id FROM t1 WHERE id IN
+(SELECT DISTINCT a.id FROM t2 a, t2 b, t2 c, t2 d
+GROUP BY ACOS(1/a.id), b.id, c.id, d.id
+HAVING a.id BETWEEN 10 AND 20);
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL @id;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+connection con1;
+Got one of the listed errors
+SELECT 1;
+1
+1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1, t2;
+connection con1;
+connection con2;
+connection con1;
+SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync WAIT_FOR kill';
+SELECT ACOS(0);
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ACOS(0)
+1.5707963267948966
+SELECT 1;
+1
+1
+SELECT @id = CONNECTION_ID();
+@id = CONNECTION_ID()
+1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+CREATE TABLE t1 (f1 INT);
+CREATE FUNCTION bug27563() RETURNS INT(11)
+DETERMINISTIC
+BEGIN
+DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
+DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
+SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
+RETURN 1;
+END|
+connection con1;
+connection con2;
+connection con1;
+INSERT INTO t1 VALUES (bug27563());
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ERROR 70100: Query execution was interrupted
+SELECT * FROM t1;
+f1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+INSERT INTO t1 VALUES(0);
+connection con1;
+UPDATE t1 SET f1= bug27563();
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ERROR 70100: Query execution was interrupted
+SELECT * FROM t1;
+f1
+0
+connection default;
+SET DEBUG_SYNC = 'RESET';
+INSERT INTO t1 VALUES(1);
+connection con1;
+DELETE FROM t1 WHERE bug27563() IS NULL;
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ERROR 70100: Query execution was interrupted
+SELECT * FROM t1;
+f1
+0
+1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+connection con1;
+SELECT * FROM t1 WHERE f1= bug27563();
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ERROR 70100: Query execution was interrupted
+SELECT * FROM t1;
+f1
+0
+1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP FUNCTION bug27563;
+CREATE TABLE t2 (f2 INT);
+CREATE TRIGGER trg27563 BEFORE INSERT ON t1 FOR EACH ROW
+BEGIN
+DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
+DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
+INSERT INTO t2 VALUES(0);
+SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
+INSERT INTO t2 VALUES(1);
+END|
+connection con1;
+INSERT INTO t1 VALUES(2),(3);
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+ERROR 70100: Query execution was interrupted
+SELECT * FROM t1;
+f1
+0
+1
+SELECT * FROM t2;
+f2
+0
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1, t2;
+#
+# Bug#19723: kill of active connection yields different error code
+# depending on platform.
+#
+connection con1;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+KILL @id;
+ERROR 70100: Connection was killed
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+connection con1;
+# ER_SERVER_SHUTDOWN, CR_SERVER_GONE_ERROR, CR_SERVER_LOST,
+# depending on the timing of close of the connection socket
+SELECT 1;
+Got one of the listed errors
+SELECT 1;
+1
+1
+SELECT @id != CONNECTION_ID();
+@id != CONNECTION_ID()
+1
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP FUNCTION MY_KILL;
+set global sql_mode=default;
+disconnect con1;
+disconnect con2;
diff --git a/mysql-test/main/kill_debug.test b/mysql-test/main/kill_debug.test
new file mode 100644
index 0000000000000..ba6a0ced52884
--- /dev/null
+++ b/mysql-test/main/kill_debug.test
@@ -0,0 +1,298 @@
+#
+# Test KILL and KILL QUERY statements.
+#
+# Killing a connection in an embedded server does not work like in a normal
+# server, if it is waiting for a new statement. In an embedded server, the
+# connection does not read() from a socket, but returns control to the
+# application. 'mysqltest' does not handle the kill request.
+#
+
+-- source include/not_embedded.inc
+-- source include/have_debug_sync.inc
+set local sql_mode="";
+set global sql_mode="";
+
+delimiter |;
+# Helper function used to repeatedly kill a session.
+CREATE FUNCTION MY_KILL(tid INT) RETURNS INT
+BEGIN
+  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN END;
+  KILL tid;
+  RETURN (SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE ID = tid);
+END|
+delimiter ;|
+
+connect con1, localhost, root;
+connect con2, localhost, root;
+
+# Save id of con1
+connection con1;
+--disable_reconnect
+let $ID= `SELECT @id := CONNECTION_ID()`;
+connection con2;
+let $ignore= `SELECT @id := $ID`;
+connection con1;
+# Signal when this connection is terminating.
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+# See if we can kill read().
+# Run into read() immediately after hitting 'before_do_command_net_read'.
+SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read';
+
+# Kill con1
+connection con2;
+SET DEBUG_SYNC='now WAIT_FOR con1_read';
+# At this point we have no way to figure out, when con1 is blocked in
+# reading from the socket. Sending KILL to early would not terminate
+# con1. So we repeat KILL until con1 terminates.
+let $wait_condition= SELECT MY_KILL(@id);
+--source include/wait_condition.inc
+# If KILL missed the read(), sync point wait will time out.
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+SET DEBUG_SYNC = 'RESET';
+
+connection con1;
+--error 1053,2006,2013,5014
+SELECT 1;
+
+--enable_reconnect
+# this should work, and we should have a new connection_id()
+SELECT 1;
+let $ignore= `SELECT @id := $ID`;
+SELECT @id != CONNECTION_ID();
+
+#make sure the server is still alive
+connection con2;
+SELECT 4;
+connection default;
+
+--error ER_SUBQUERIES_NOT_SUPPORTED
+KILL (SELECT COUNT(*) FROM mysql.user);
+
+connection con1;
+let $ID= `SELECT @id := CONNECTION_ID()`;
+connection con2;
+let $ignore= `SELECT @id := $ID`;
+connection con1;
+disable_reconnect;
+# Signal when this connection is terminating.
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+# See if we can kill the sync point itself.
+# Wait in 'before_do_command_net_read' until killed.
+# It doesn't wait for a signal 'kill' but for to be killed.
+# The signal name doesn't matter here.
+SET DEBUG_SYNC= 'before_do_command_net_read SIGNAL con1_read WAIT_FOR kill';
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_read';
+# Repeat KILL until con1 terminates.
+let $wait_condition= SELECT MY_KILL(@id);
+--source include/wait_condition.inc
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+SET DEBUG_SYNC = 'RESET';
+
+connection con1;
+--error 1053,2006,2013,5014
+SELECT 1;
+enable_reconnect;
+SELECT 1;
+let $ignore= `SELECT @id := $ID`;
+SELECT @id != CONNECTION_ID();
+connection con2;
+SELECT 4;
+connection default;
+
+#
+# BUG#14851: killing long running subquery processed via a temporary table.
+#
+
+CREATE TABLE t1 (id INT PRIMARY KEY AUTO_INCREMENT);
+CREATE TABLE t2 (id INT UNSIGNED NOT NULL);
+
+INSERT INTO t1 VALUES
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0), (0),(0),(0),(0),(0),(0),(0),(0);
+INSERT t1 SELECT 0 FROM t1 AS a1, t1 AS a2 LIMIT 4032;
+
+INSERT INTO t2 SELECT id FROM t1;
+
+connection con1;
+let $ID= `SELECT @id := CONNECTION_ID()`;
+connection con2;
+let $ignore= `SELECT @id := $ID`;
+
+connection con1;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync';
+# This is a very long running query. If this test start failing,
+# it may be necessary to change to an even longer query.
+send SELECT id FROM t1 WHERE id IN
+       (SELECT DISTINCT a.id FROM t2 a, t2 b, t2 c, t2 d
+          GROUP BY ACOS(1/a.id), b.id, c.id, d.id
+          HAVING a.id BETWEEN 10 AND 20);
+
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL @id;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+
+connection con1;
+--error 1317,1053,2006,2013,5014
+reap;
+SELECT 1;
+
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1, t2;
+
+#
+# Test of blocking of sending ERROR after OK or EOF
+#
+connection con1;
+let $ID= `SELECT @id := CONNECTION_ID()`;
+connection con2;
+let $ignore= `SELECT @id := $ID`;
+connection con1;
+SET DEBUG_SYNC= 'before_acos_function SIGNAL in_sync WAIT_FOR kill';
+send SELECT ACOS(0);
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+reap;
+SELECT 1;
+SELECT @id = CONNECTION_ID();
+connection default;
+SET DEBUG_SYNC = 'RESET';
+
+#
+# Bug#27563: Stored functions and triggers wasn't throwing an error when killed.
+#
+CREATE TABLE t1 (f1 INT);
+delimiter |;
+CREATE FUNCTION bug27563() RETURNS INT(11)
+DETERMINISTIC
+BEGIN
+  DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
+  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
+  SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
+  RETURN 1;
+END|
+delimiter ;|
+# Test stored functions
+# Test INSERT
+connection con1;
+let $ID= `SELECT @id := CONNECTION_ID()`;
+connection con2;
+let $ignore= `SELECT @id := $ID`;
+connection con1;
+send INSERT INTO t1 VALUES (bug27563());
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+--error 1317
+reap;
+SELECT * FROM t1;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+
+# Test UPDATE
+INSERT INTO t1 VALUES(0);
+connection con1;
+send UPDATE t1 SET f1= bug27563();
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+--error 1317
+reap;
+SELECT * FROM t1;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+
+# Test DELETE
+INSERT INTO t1 VALUES(1);
+connection con1;
+send DELETE FROM t1 WHERE bug27563() IS NULL;
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+--error 1317
+reap;
+SELECT * FROM t1;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+
+# Test SELECT
+connection con1;
+send SELECT * FROM t1 WHERE f1= bug27563();
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+--error 1317
+reap;
+SELECT * FROM t1;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP FUNCTION bug27563;
+
+# Test TRIGGERS
+CREATE TABLE t2 (f2 INT);
+delimiter |;
+CREATE TRIGGER trg27563 BEFORE INSERT ON t1 FOR EACH ROW
+BEGIN
+  DECLARE CONTINUE HANDLER FOR SQLSTATE '70100' SET @a:= 'killed';
+  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET @a:= 'exception';
+  INSERT INTO t2 VALUES(0);
+  SET DEBUG_SYNC= 'now SIGNAL in_sync WAIT_FOR kill';
+  INSERT INTO t2 VALUES(1);
+END|
+delimiter ;|
+connection con1;
+send INSERT INTO t1 VALUES(2),(3);
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR in_sync';
+KILL QUERY @id;
+connection con1;
+--error 1317
+reap;
+SELECT * FROM t1;
+SELECT * FROM t2;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t1, t2;
+
+--echo #
+--echo # Bug#19723: kill of active connection yields different error code
+--echo # depending on platform.
+--echo #
+
+--connection con1
+let $ID= `SELECT @id := CONNECTION_ID()`;
+SET DEBUG_SYNC= 'thread_end SIGNAL con1_end';
+--disable_reconnect
+--error ER_CONNECTION_KILLED
+KILL @id;
+
+connection con2;
+SET DEBUG_SYNC= 'now WAIT_FOR con1_end';
+connection con1;
+--echo # ER_SERVER_SHUTDOWN, CR_SERVER_GONE_ERROR, CR_SERVER_LOST,
+--echo # depending on the timing of close of the connection socket
+--error 1053,2006,2013,5014
+SELECT 1;
+--enable_reconnect
+SELECT 1;
+let $ignore= `SELECT @id := $ID`;
+SELECT @id != CONNECTION_ID();
+connection default;
+
+SET DEBUG_SYNC = 'RESET';
+DROP FUNCTION MY_KILL;
+
+set global sql_mode=default;
+disconnect con1;
+disconnect con2;

From de130323b4401ba9dfcb08ebd7f8d688cb317a80 Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Wed, 28 Sep 2022 14:27:55 +0200
Subject: [PATCH 4/6] MDEV-29368 Assertion `trx->mysql_thd == thd' failed in
 innobase_kill_query from process_timers/timer_handler and use-after-poison in
 innobase_kill_query

This is a 10.5 version of 9b750dcbd89e, fix for
MDEV-23536 Race condition between KILL and transaction commit

InnoDB needs to remove trx from thd before destroying it (trx), otherwise
a concurrent KILL might get a pointer from thd to a destroyed trx.

ha_close_connection() should allow engines to clear ha_data in
hton->on close_connection(). To prevent the engine from being unloaded
while hton->close_connection() is running, we remove the lock from
ha_data and unlock the plugin manually.
---
 mysql-test/main/kill_debug.result     | 16 ++++++++++++++++
 mysql-test/main/kill_debug.test       | 20 ++++++++++++++++++++
 sql/handler.cc                        |  9 ++++-----
 sql/sql_class.cc                      |  2 ++
 sql/sql_parse.cc                      |  2 +-
 storage/innobase/handler/ha_innodb.cc |  2 ++
 6 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/mysql-test/main/kill_debug.result b/mysql-test/main/kill_debug.result
index d0fadb5c7b5a3..061e760238396 100644
--- a/mysql-test/main/kill_debug.result
+++ b/mysql-test/main/kill_debug.result
@@ -221,3 +221,19 @@ DROP FUNCTION MY_KILL;
 set global sql_mode=default;
 disconnect con1;
 disconnect con2;
+#
+# MDEV-29368 Assertion `trx->mysql_thd == thd' failed in innobase_kill_query from process_timers/timer_handler and use-after-poison in innobase_kill_query
+#
+connect foo,localhost,root;
+create table t1 (a int) engine=innodb;
+insert t1 values (1);
+set debug_sync='THD_cleanup_after_set_killed SIGNAL go0 WAIT_FOR go1';
+set debug_sync='innobase_connection_closed SIGNAL go2 WAIT_FOR go3';
+disconnect foo;
+connection default;
+set debug_sync='now WAIT_FOR go0';
+set debug_sync='found_killee SIGNAL go1 WAIT_FOR go2';
+kill $id;
+set debug_sync='now SIGNAL go3';
+drop table t1;
+set debug_sync='reset';
diff --git a/mysql-test/main/kill_debug.test b/mysql-test/main/kill_debug.test
index ba6a0ced52884..32a764004e3eb 100644
--- a/mysql-test/main/kill_debug.test
+++ b/mysql-test/main/kill_debug.test
@@ -9,6 +9,7 @@
 
 -- source include/not_embedded.inc
 -- source include/have_debug_sync.inc
+-- source include/have_innodb.inc
 set local sql_mode="";
 set global sql_mode="";
 
@@ -296,3 +297,22 @@ DROP FUNCTION MY_KILL;
 set global sql_mode=default;
 disconnect con1;
 disconnect con2;
+
+--echo #
+--echo # MDEV-29368 Assertion `trx->mysql_thd == thd' failed in innobase_kill_query from process_timers/timer_handler and use-after-poison in innobase_kill_query
+--echo #
+connect foo,localhost,root;
+let $id=`select connection_id()`;
+create table t1 (a int) engine=innodb;
+insert t1 values (1);
+set debug_sync='THD_cleanup_after_set_killed SIGNAL go0 WAIT_FOR go1';
+set debug_sync='innobase_connection_closed SIGNAL go2 WAIT_FOR go3';
+disconnect foo;
+
+connection default;
+set debug_sync='now WAIT_FOR go0';
+set debug_sync='found_killee SIGNAL go1 WAIT_FOR go2';
+evalp kill $id;
+set debug_sync='now SIGNAL go3';
+drop table t1;
+set debug_sync='reset';
diff --git a/sql/handler.cc b/sql/handler.cc
index 0d5609f753ac1..85600d02b63f5 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -894,15 +894,14 @@ void ha_close_connection(THD* thd)
 {
   for (auto i= 0; i < MAX_HA; i++)
   {
-    if (thd->ha_data[i].lock)
+    if (plugin_ref plugin= thd->ha_data[i].lock)
     {
-      handlerton *hton= plugin_hton(thd->ha_data[i].lock);
+      thd->ha_data[i].lock= NULL;
+      handlerton *hton= plugin_hton(plugin);
       if (hton->close_connection)
         hton->close_connection(hton, thd);
-      /* make sure SE didn't reset ha_data in close_connection() */
-      DBUG_ASSERT(thd->ha_data[i].lock);
-      /* make sure ha_data is reset and ha_data_lock is released */
       thd_set_ha_data(thd, hton, 0);
+      plugin_unlock(NULL, plugin);
     }
     DBUG_ASSERT(!thd->ha_data[i].ha_ptr);
   }
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 87526acbdbae2..87f5262f9cea5 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -1533,6 +1533,8 @@ void THD::cleanup(void)
   wsrep_client_thread= false;
 #endif /* WITH_WSREP */
 
+  DEBUG_SYNC(this, "THD_cleanup_after_set_killed");
+
   mysql_ha_cleanup(this);
   locked_tables_list.unlock_locked_tables(this);
 
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index ec22b5396683c..643d671878fc3 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -9271,7 +9271,7 @@ kill_one_thread(THD *thd, longlong id, killed_state kill_signal, killed_type typ
   tmp= find_thread_by_id(id, type == KILL_TYPE_QUERY);
   if (!tmp)
     DBUG_RETURN(error);
-
+  DEBUG_SYNC(thd, "found_killee");
   if (tmp->get_command() != COM_DAEMON)
   {
     /*
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 25f2f4d635ffa..4a710a5c38440 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -4791,6 +4791,7 @@ static int innobase_close_connection(handlerton *hton, THD *thd)
   DBUG_ASSERT(hton == innodb_hton_ptr);
   if (auto trx= thd_to_trx(thd))
   {
+    thd_set_ha_data(thd, innodb_hton_ptr, NULL);
     if (trx->state == TRX_STATE_PREPARED && trx->has_logged_persistent())
     {
       trx_disconnect_prepared(trx);
@@ -4798,6 +4799,7 @@ static int innobase_close_connection(handlerton *hton, THD *thd)
     }
     innobase_rollback_trx(trx);
     trx->free();
+    DEBUG_SYNC(thd, "innobase_connection_closed");
   }
   return 0;
 }

From 6b685ea7b0776430d45b095cb4be3ef0739a3c04 Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Wed, 28 Sep 2022 18:55:15 +0200
Subject: [PATCH 5/6] correctness assert

thd_get_ha_data() can be used without a lock, but only from the
current thd thread, when calling from anoher thread it *must*
be protected by thd->LOCK_thd_data

* fix group commit code to take thd->LOCK_thd_data
* remove innobase_close_connection() from the innodb background thread,
  it's not needed after 87775402cd0c and was failing the assert with
  current_thd==0
---
 include/my_pthread.h                  | 1 +
 sql/log.cc                            | 4 ++++
 sql/sql_class.cc                      | 1 +
 storage/innobase/handler/ha_innodb.cc | 4 ----
 4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/my_pthread.h b/include/my_pthread.h
index f5bfda49a28c3..1c83e77a41bb2 100644
--- a/include/my_pthread.h
+++ b/include/my_pthread.h
@@ -437,6 +437,7 @@ void safe_mutex_free_deadlock_data(safe_mutex_t *mp);
 #define my_cond_wait(A,B) safe_cond_wait((A), (B), __FILE__, __LINE__)
 #else
 
+#define safe_mutex_is_owner(mp) (1)
 #define safe_mutex_assert_owner(mp) do {} while (0)
 #define safe_mutex_assert_not_owner(mp) do {} while (0)
 #define safe_mutex_setflags(mp, F) do {} while (0)
diff --git a/sql/log.cc b/sql/log.cc
index c679e8f5111fa..ec21282578718 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -8512,7 +8512,11 @@ MYSQL_BIN_LOG::trx_group_commit_leader(group_commit_entry *leader)
     ++num_commits;
     if (current->cache_mngr->using_xa && likely(!current->error) &&
         DBUG_EVALUATE_IF("skip_commit_ordered", 0, 1))
+    {
+      mysql_mutex_lock(&current->thd->LOCK_thd_data);
       run_commit_ordered(current->thd, current->all);
+      mysql_mutex_unlock(&current->thd->LOCK_thd_data);
+    }
     current->thd->wakeup_subsequent_commits(current->error);
 
     /*
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 87f5262f9cea5..cd80602a9f297 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -462,6 +462,7 @@ void thd_storage_lock_wait(THD *thd, long long value)
 extern "C"
 void *thd_get_ha_data(const THD *thd, const struct handlerton *hton)
 {
+  DBUG_ASSERT(thd == current_thd ||  mysql_mutex_is_owner(&thd->LOCK_thd_data));
   return thd->ha_data[hton->slot].ha_ptr;
 }
 
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 4a710a5c38440..a3184abd2d34f 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -1484,10 +1484,6 @@ innobase_destroy_background_thd(
 /*============================*/
 	MYSQL_THD thd)
 {
-	/* need to close the connection explicitly, the server won't do it
-	if innodb is in the PLUGIN_IS_DYING state */
-	innobase_close_connection(innodb_hton_ptr, thd);
-	thd_set_ha_data(thd, innodb_hton_ptr, NULL);
 	destroy_background_thd(thd);
 }
 

From e29fb956145cfa1f4f8c41cafcddea36a20b23aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Fri, 30 Sep 2022 08:25:00 +0300
Subject: [PATCH 6/6] Cleanup: Remove innobase_destroy_background_thd()

We do not need a non-inline wrapper for the function
destroy_background_thd().
---
 storage/innobase/fts/fts0opt.cc          |  2 +-
 storage/innobase/handler/ha_innodb.cc    | 11 -----------
 storage/innobase/include/ha_prototypes.h |  7 +++----
 storage/innobase/srv/srv0srv.cc          |  2 +-
 4 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/storage/innobase/fts/fts0opt.cc b/storage/innobase/fts/fts0opt.cc
index 348566ae9525a..9e3b4b3121d27 100644
--- a/storage/innobase/fts/fts0opt.cc
+++ b/storage/innobase/fts/fts0opt.cc
@@ -2965,7 +2965,7 @@ static void fts_optimize_callback(void *)
 	ib_wqueue_free(fts_optimize_wq);
 	fts_optimize_wq = NULL;
 
-	innobase_destroy_background_thd(fts_opt_thd);
+	destroy_background_thd(fts_opt_thd);
 	ib::info() << "FTS optimize thread exiting.";
 
 	os_event_set(fts_opt_shutdown_event);
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index a3184abd2d34f..e18d0d5968c47 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -127,7 +127,6 @@ void thd_clear_error(MYSQL_THD thd);
 TABLE *find_fk_open_table(THD *thd, const char *db, size_t db_len,
 			  const char *table, size_t table_len);
 MYSQL_THD create_background_thd();
-void destroy_background_thd(MYSQL_THD thd);
 void reset_thd(MYSQL_THD thd);
 TABLE *get_purge_table(THD *thd);
 TABLE *open_purge_table(THD *thd, const char *db, size_t dblen,
@@ -1477,16 +1476,6 @@ innobase_create_background_thd(const char* name)
 }
 
 
-/** Destroy a background purge thread THD.
-@param[in]	thd	MYSQL_THD to destroy */
-void
-innobase_destroy_background_thd(
-/*============================*/
-	MYSQL_THD thd)
-{
-	destroy_background_thd(thd);
-}
-
 /** Close opened tables, free memory, delete items for a MYSQL_THD.
 @param[in]	thd	MYSQL_THD to reset */
 void
diff --git a/storage/innobase/include/ha_prototypes.h b/storage/innobase/include/ha_prototypes.h
index c1c41a8f77c56..04e1ec96b7352 100644
--- a/storage/innobase/include/ha_prototypes.h
+++ b/storage/innobase/include/ha_prototypes.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2006, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2021, MariaDB Corporation.
+Copyright (c) 2017, 2022, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -512,10 +512,9 @@ innodb_set_buf_pool_size(ulonglong buf_pool_size);
 MYSQL_THD
 innobase_create_background_thd(const char* name);
 
-/** Destroy a background purge thread THD.
+/** Destroy a THD object associated with a background task.
 @param[in]	thd	MYSQL_THD to destroy */
-void
-innobase_destroy_background_thd(MYSQL_THD);
+void destroy_background_thd(MYSQL_THD thd);
 
 /** Close opened tables, free memory, delete items for a MYSQL_THD.
 @param[in]	thd	MYSQL_THD to reset */
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index a33d34c565434..f8e02f95c5e35 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -2003,7 +2003,7 @@ static void srv_shutdown_purge_tasks()
   std::unique_lock<std::mutex> lk(purge_thd_mutex);
   while (!purge_thds.empty())
   {
-    innobase_destroy_background_thd(purge_thds.front());
+    destroy_background_thd(purge_thds.front());
     purge_thds.pop_front();
   }
   n_purge_thds= 0;