cannot be cast to class com.mysql.cj.jdbc.ClientPreparedStatement

[Tomonori Iida]

Hi
We are developing a multi-threaded batch application on Spring Boot 2.7.8 + Aurora MySQL 2.11.1 (primary-db/replica-db).
I am having trouble with ClassCastException when updating/inserting data into a table.
If I update only one item, ClassCastException is not raised.
Only when updating a large number of n updates, the ClassCastException is always thrown.
Also, when I connect with MariaDB Connector/J 2.5.4 instead of MySQL Connector/J 8.0.32, no ClassCastException occurs even for mass updates.
I would say that using MariaDB Connector/J would solve the problem, but..,

# HikariCP
## MySQL Connector/J
- name: "default"
dataSource:
driverClassName: "com.mysql.cj.jdbc.Driver"
jdbcUrl: "jdbc:mysql:replication://\
primary-db:3306\
,replica-db:3306\
?rewriteBatchedStatements=true&sessionVariables=character_set_connection=utf8mb4,collation_connection=utf8mb4_general_ci&socketTimeout=300000"
username: "root"
password: ""
autoCommit: true
readOnly: false
connectionTimeout: 300000
idleTimeout: 600000
minimumIdle: 2
maximumPoolSize: 10
connectionTestQuery: "SELECT 1"

## MariaDB Connector/J
hikari:
- name: "default"
dataSource:
driverClassName: "org.mariadb.jdbc.Driver"
jdbcUrl: "jdbc:mysql:aurora://\
primary-db:3306\
,replica-db:3306\
?rewriteBatchedStatements=true&sessionVariables=character_set_connection=utf8mb4,collation_connection=utf8mb4_general_ci&socketTimeout=300000"
username: "root"
password: ""
autoCommit: true
readOnly: false
connectionTimeout: 300000
idleTimeout: 600000
minimumIdle: 2
maximumPoolSize: 10
connectionTestQuery: "SELECT 1"

# ClassCastException
2023-xx-xx xx:yy:zz [ForkJoinPool-4-worker-23] ERROR o.h.e.j.b.i.BatchingBatch -> HHH000315: Exception executing batch [java.lang.ClassCastException: class com.sun.proxy.$Proxy186 cannot be cast to class com.mysql.cj.jdbc.ClientPreparedStatement (com.sun.proxy.$Proxy186 and com.mysql.cj.jdbc.ClientPreparedStatement are in unnamed module of loader org.springframework.boot.loader.LaunchedURLClassLoader @7823a2f9)], SQL: update test.table1 set updated_at=?, account_id=?, hoge_formats=?, hoge_type=?, body=?, action_type=?, cr_type=?, story_id=?, hash=?, name=?, story_spec=?, object_type=?, status=?, title=?, video_id=? where id=?

# DDL
CREATE TABLE `test`.`table1` (
`id` bigint(20) NOT NULL,
`account_id` varchar(128) NOT NULL,
`hash` varchar(128) DEFAULT NULL,
`video_id` varchar(128) DEFAULT NULL,
`action_type` varchar(128) DEFAULT NULL,
`title` varchar(512) DEFAULT NULL,
`body` mediumtext,
`name` varchar(256) DEFAULT NULL,
`story_id` varchar(192) DEFAULT NULL,
`object_type` varchar(32) DEFAULT NULL,
`cr_type` varchar(32) NOT NULL,
`status` varchar(64) NOT NULL,
`story_spec` json DEFAULT NULL,
`hoge_type` varchar(128) DEFAULT NULL,
`hoge_formats` varchar(255) DEFAULT NULL,
`created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
`updated_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `idx_accid` (`account_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

# Entity
@EqualsAndHashCode(callSuper = false)
@Builder
@NoArgsConstructor
@AllArgsConstructor(staticName = "of")
@Data
@Entity
@Table(catalog = "test", name = "table1")
public class Table1 extends BaseEntity {
private static final long serialVersionUID = 1L;
@Id
private BigInteger id;
private String accountId;
private String hash;
private String videoId;
@Enumerated(EnumType.STRING)
private ActionType actionType;
private String title;
private String body;
private String name;
private String storyId;
@Enumerated(EnumType.STRING)
private ObjectType objectType;
@Convert(converter = CrTypeToStringConverter.class)
private CrType crType;
@Enumerated(EnumType.STRING)
private Status status;
@Convert(converter = StorySpecToStringConverter.class)
private StorySpec storySpec;
@Enumerated(EnumType.STRING)
private HogeType hogeType;
@Convert(converter = StringsToStringConverter.class)
private List<String> hogeFormats;
}


Please advise if you have any suggestions.