MySql innoDB auto increment lock workaround - mysql

Question

I have a project in which I insert a lot if info to a table with an auto increment primary key per second and do that with multi-threading which means that there are many threads that tries to insert a new row to that table. Because there is a lock on the table for insert queries, I cant perform inserts concurrently and therefore I cant get maximum performance from the threads...
Is there a way to overcome this lock?

Answer 1

You can set the innodb_autoinc_lock_mode to 1 in the my.cnf. Then there is no LOCK for Auto_increment. Then it is possible that you have holes in the Values if one Thead rollback an see sample
MariaDB [test]> show variables like 'innodb_autoinc_lock_mode';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| innodb_autoinc_lock_mode | 1 |
+--------------------------+-------+
1 row in set (0.00 sec)
sample 1
MariaDB [test]> start transaction;
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> insert into autoinc VALUES(NULL,'hello');
Query OK, 1 row affected (0.01 sec)
thread 2 ------------------> MariaDB [test]> start transaction;
thread 2 ------------------> Query OK, 0 rows affected (0.00 sec)
thread 2 ------------------> MariaDB [test]> insert into autoinc VALUES(NULL,'world');
thread 2 ------------------> Query OK, 1 row affected (0.00 sec)
thread 2 ------------------> MariaDB [test]> commit;
thread 2 ------------------> Query OK, 0 rows affected (0.00 sec)
thread 2 ------------------> MariaDB [test]>
MariaDB [test]> commit;
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> select * from autoinc;
+----+-------+
| id | d |
+----+-------+
| 1 | hello |
| 2 | world |
+----+-------+
2 rows in set (0.00 sec)
MariaDB [test]>
sample 2 with rollback
MariaDB [test]> start transaction;
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> insert into autoinc VALUES(NULL,'Guten');
Query OK, 1 row affected (0.00 sec)
thread 2 ------------------> MariaDB [test]> start transaction;
thread 2 ------------------> Query OK, 0 rows affected (0.00 sec)
thread 2 ------------------> MariaDB [test]> insert into autoinc VALUES(NULL,'Tag');
thread 2 ------------------> Query OK, 1 row affected (0.00 sec)
thread 2 ------------------> MariaDB [test]> commit;
thread 2 ------------------> Query OK, 0 rows affected (0.01 sec)
MariaDB [test]> rollback;
Query OK, 0 rows affected (0.00 sec)
MariaDB [test]> select * from autoinc;
+----+-------+
| id | d |
+----+-------+
| 1 | hello |
| 2 | world |
| 4 | Tag |
+----+-------+
3 rows in set (0.00 sec)
MariaDB [test]>