Inconsistent Hibernate Behavior while using GenerationType.SEQUENCE

33 views Asked by At

I see inconsistent hibernate behavior when using sequence to generate id, I have simple project with one entity Fruit and I'm using spring.jpa.hibernate.ddl-auto=create-drop so hibernate is launching create sequence fruit_seq start with 1 increment by 50 nocache now the issue is when I create fruits in following sequence

curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "apple"
}'
curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "mango"
}'

then run this query manually

select next value for fruit_seq; -- returns 101

then again I create a third fruit

curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "orange"
}'

I get id correctly without any affect from my external next_val query that returned 101

MariaDB [fruits]> select * from fruit;
+----+------------+
| id | fruit_name |
+----+------------+
|  1 | apple      |
|  2 | mango      |
+----+------------+
2 rows in set (0.001 sec)

MariaDB [fruits]> select next value for fruit_seq;
+--------------------------+
| next value for fruit_seq |
+--------------------------+
|                      101 |
+--------------------------+
1 row in set (0.001 sec)

MariaDB [fruits]> select * from fruit;
+----+------------+
| id | fruit_name |
+----+------------+
|  1 | apple      |
|  2 | mango      |
|  3 | orange     |
+----+------------+
3 rows in set (0.001 sec)

however when I do same experiment just change the order in which I create fruits and externally manipulate next_val hibernate reflect the external effect

curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "apple"
}'

then run this query manually

select next value for fruit_seq; -- returns 51

then create second and third fruit

curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "mango"
}'
curl --location 'http://localhost:8080/fruits' \
--header 'Content-Type: application/json' \
--data '{
    "name": "orange"
}'

this affects the ids generated by hibernate

MariaDB [fruits]> select * from fruit;
+----+------------+
| id | fruit_name |
+----+------------+
|  1 | apple      |
+----+------------+
1 row in set (0.001 sec)

MariaDB [fruits]> select next value for fruit_seq;
+--------------------------+
| next value for fruit_seq |
+--------------------------+
|                       51 |
+--------------------------+
1 row in set (0.001 sec)

MariaDB [fruits]> select * from fruit;
+----+------------+
| id | fruit_name |
+----+------------+
|  1 | apple      |
| 52 | mango      |
| 53 | orange     |
+----+------------+
3 rows in set (0.001 sec)

I was expecting hibernate to always get affected by external manipulations but it does not in the case when you off start by 2 fruits

0

There are 0 answers