[#MDEV-20543] Latching order violation during B-tree operations

It turns out that there are more causes to ~~MDEV-14637~~ than the too small secondary index record size estimates that were fixed in MySQL 5.7.23.

With the following patch (extracted from ~~MDEV-19514~~) applied to MySQL 5.7 or MariaDB Server 10.2 or later, the bug is repeatable:

diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc

index 4f9ecf10ec7..ecd90053d68 100644

--- a/storage/innobase/buf/buf0buf.cc

+++ b/storage/innobase/buf/buf0buf.cc

@@ -4617,6 +4617,8 @@ got_block:

 		fix_block->made_dirty_with_no_latch = dirty_with_no_latch;

+	rw_lock_x_lock(&block->lock);

+	rw_lock_x_unlock(&block->lock);

 	mtr_memo_type_t	fix_type;

 	switch (rw_latch) {

./mtr --big-test --mysqld=--innodb-page-size=4k innodb.innodb_bulk_create_index

mysql-5.7.27
CURRENT_TEST: innodb.innodb_bulk_create_index
mysqltest: In included file ./suite/innodb/include/innodb_bulk_create_index.inc at line 84:
included from /mariadb/mysql-server/mysql-test/suite/innodb/t/innodb_bulk_create_index.test at line 41:
At line 84: query 'SELECT * FROM t1 WHERE title = 'a3000'' failed: 2013: Lost connection to MySQL server during query
…
Version: '5.7.27-debug-log' socket: '/dev/shm/5.7/mysql-test/var/tmp/mysqld.1.sock' port: 13000 Source distribution
########################################
DEADLOCK of threads detected!
rw-lock 0x7f188e748968 --Thread 139743545079552 has waited at buf0buf.cc line 4620 for 0 seconds the semaphore:
X-lock on RW-latch at 0x7f188e748968 created in file buf0buf.cc line 1460
a writer (thread id 139743127922432) has reserved it in mode exclusive
number of readers 0, waiters flag 1, lock_word: 0
Last time read locked in file row0row.cc line 1075
Last time write locked in file /mariadb/mysql-server/storage/innobase/include/mtr0mtr.ic line 153
Locked: thread 139743127922432 file mtr0mtr.ic line 153 X-LOCK
Locked: thread 139743127922432 file mtr0mtr.ic line 153 X-LOCK
rw-lock 0x7f188e72a030 --Thread 139743127922432 has waited at buf0buf.cc line 4620 for 0 seconds the semaphore:
X-lock (wait_ex) on RW-latch at 0x7f188e72a030 created in file buf0buf.cc line 1460
a writer (thread id 139743127922432) has reserved it in mode wait exclusive
number of readers 1, waiters flag 0, lock_word: ffffffffefffffff
Last time read locked in file btr0cur.cc line 5736
Last time write locked in file /mariadb/mysql-server/storage/innobase/include/mtr0mtr.ic line 117
Locked: thread 139743545079552 file btr0cur.cc line 5736 S-LOCK
Locked: thread 139743545079552 file btr0cur.cc line 5736 S-LOCK
2019-09-10T07:31:49.289423Z 0 [ERROR] [FATAL] InnoDB: ######################################## Deadlock Detected!

[MDEV-20543] Latching order violation during B-tree operations Created: 2019-09-10 Updated: 2019-11-22 Resolved: 2019-11-22
Status:	Closed
Project:	MariaDB Server
Component/s:	Storage Engine - InnoDB
Affects Version/s:	10.2.2, 10.3.0, 10.4.0
Fix Version/s:	N/A

[MDEV-20543] Latching order violation during B-tree operations Created: 2019-09-10 Updated: 2019-11-22 Resolved: 2019-11-22