MySQL allows multiple next-key locks on same record - mysql

Question

Is MySQL allows multiple next-key locks on same record/range from multiple sessions? As following example shows, the same delete statement won't block each other.
My understanding is MySQL support MVCC, which means it has snapshot for each sessions below. Am I right?
MySQL: 5.7
Isolation level: Repeatable Read
Database: innodb
CREATE TABLE `game_summaries` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`game_id` int(11) DEFAULT NULL,
`value` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `index_game_summaries_on_game_id` (`game_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
session 1
start transaction;
delete from game_summaries where game_id = 2;
session 2
start transaction;
delete from game_summaries where game_id = 2;
run show engine innodb status \G to get all locks
------------
TRANSACTIONS
------------
Trx id counter 2849
Purge done for trx's n:o < 2841 undo n:o < 0 state: running but idle
History list length 0
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 2848, ACTIVE 8 sec
2 lock struct(s), heap size 1136, 1 row lock(s)
MySQL thread id 3, OS thread handle 139644825081600, query id 232 172.18.0.1 root starting
show engine innodb status
TABLE LOCK table `test`.`game_summaries` trx id 2848 lock mode IX
RECORD LOCKS space id 27 page no 4 n bits 72 index index_game_summaries_on_game_id of table `test`.`game_summaries` trx id 2848 lock_mode X
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
---TRANSACTION 2847, ACTIVE 18 sec
2 lock struct(s), heap size 1136, 1 row lock(s)
MySQL thread id 2, OS thread handle 139644825351936, query id 229 172.18.0.1 root
TABLE LOCK table `test`.`game_summaries` trx id 2847 lock mode IX
RECORD LOCKS space id 27 page no 4 n bits 72 index index_game_summaries_on_game_id of table `test`.`game_summaries` trx id 2847 lock_mode X
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;

Answer 1

According to https://dev.mysql.com/doc/refman/8.0/en/innodb-locking.html, the gap lock is allowed to be hold on a gap by different transactions, even you saw lock_mode X there.
It is also worth noting here that conflicting locks can be held on a gap by different transactions. For example, transaction A can hold a shared gap lock (gap S-lock) on a gap while transaction B holds an exclusive gap lock (gap X-lock) on the same gap. The reason conflicting gap locks are allowed is that if a record is purged from an index, the gap locks held on the record by different transactions must be merged.