MySQL5.7 REPEATABLE READ TRANSACTION ISOLATION level study.

The transaction isolation level is repeatable read in case

Transaction 2 does not execute a commit and cannot read the newly added record for transaction 1.

Transaction 2 executes a commit and can read the newly added record to transaction 1.

Session1 Execution Transaction 1: Insert and commit only

Mysql> SELECT @ @tx_isolation;

+-----------------+

| @ @tx_isolation |

+-----------------+

| Repeatable-read |

+-----------------+

1 row in Set (0.00 sec)

Mysql>

mysql> start transaction;

Query OK, 0 rows Affected (0.00 sec)

Mysql> select * from Lisa;

+------------+------+

| name | Age |

+------------+------+

|   Lisa | 99 |

|   Sunlongwei | 27 |

|  Shabala | 999 |

| Balabala | 9999 |

| Balabala | 9999 |

| hehe | 9999 |

| hehe | 9999 |

|    bb | 1 |

|    bb | 2 |

|    bb | 3 |

+------------+------+

Rows in Set (0.00 sec)

Mysql> INSERT into Lisa values (' AA ', ' 9999 ');

Query OK, 1 row Affected (0.00 sec)

Mysql> INSERT into Lisa values (' CC ', ' 9999 ');

Query OK, 1 row Affected (0.00 sec)

Mysql> commit;

Query OK, 0 rows Affected (0.00 sec)

Mysql> select * from Lisa;

+------------+------+

| name | Age |

+------------+------+

|   Lisa | 99 |

|   Sunlongwei | 27 |

|  Shabala | 999 |

| Balabala | 9999 |

| Balabala | 9999 |

| hehe | 9999 |

| hehe | 9999 |

|    bb | 1 |

|    bb | 2 |

|    bb | 3 |

| AA | 9999 |

| CC | 9999 |

+------------+------+

Rows in Set (0.00 sec)

Session2 Execution Transaction 2: Query and commit only

mysql> start transaction;

Query OK, 0 rows Affected (0.00 sec)

Mysql> select * from Lisa;

+------------+------+

| name | Age |

+------------+------+

|   Lisa | 99 |

|   Sunlongwei | 27 |

|  Shabala | 999 |

| Balabala | 9999 |

| Balabala | 9999 |

| hehe | 9999 |

| hehe | 9999 |

|    bb | 1 |

|    bb | 2 |

|    bb | 3 |

+------------+------+

Rows in Set (0.00 sec)

Transaction 2 cannot query to a record inserted in transaction 1 if not committed

Mysql> commit;

Query OK, 0 rows Affected (0.00 sec)

Mysql> select * from Lisa;

+------------+------+

| name | Age |

+------------+------+

|   Lisa | 99 |

|   Sunlongwei | 27 |

|  Shabala | 999 |

| Balabala | 9999 |

| Balabala | 9999 |

| hehe | 9999 |

| hehe | 9999 |

|    bb | 1 |

|    bb | 2 |

|    bb | 3 |

| AA | 9999 |

| CC | 9999 |

+------------+------+

Transaction 2 can be queried for records inserted in transaction 1 after commit

MySQL5.7 REPEATABLE READ TRANSACTION ISOLATION level study.