Hibernate-core-5.3.15 (SpringBoot2.1.12) DynamicUpdate BLOB problem

Hibernate ORM
1

I’m trying to exclude the unchanged BLOB column from generated update statement. My simplified entity with the @DynamicUpdate annotation is as follows:

@Entity
@DynamicUpdate
public class Part {
    @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "PartSequence")
    @SequenceGenerator(name = "PartSequence", sequenceName = "part_seq", allocationSize = 1)
    @Column(name = "id")
    private Long id;
    public Long getId() {
        return this.id;
    }
    public Part setId(Long id) {
        this.id = id;
        return this;
    }

    @Column(name = "part_number")
    private Integer partNumber;
    public Integer getPartNumber() {
        return this.partNumber;
    }
    public Part setPartNumber(Integer partNumber) {
        this.partNumber = partNumber;
        return this;
    }

    @Column(name = "create_datetime")
    private LocalDateTime createDateTime;
    public LocalDateTime getCreateDateTime() {
        return this.createDateTime;
    }
    public Part setCreateDateTime(LocalDateTime createDateTime) {
        this.createDateTime = createDateTime;
        return this;
    }

    @Lob
    @Column(name = "content", columnDefinition = "blob")
    private Blob content;
    public Blob getContent() {
        return this.content;
    }
    public Part setContent(Blob content) {
        this.content = content;
        return this;
    }

    @Version
    @Column(name = "version")
    private Long version;
}

The corresponding JPA repository implementation is below:

@Repository
public interface PartRepository extends JpaRepository<Part, Long> { }

and the snippet of test code:

@RunWith(SpringRunner.class)
@SpringBootTest
public class ExtraupdateApplicationTests {
    @Autowired
    private PartRepository partRepository;

    @Test
    public void testExtraUpdate() {
        Part part = this.partRepository.save(new Part());

        part.setPartNumber(1);
        part = this.partRepository.save(part); //1

        byte[] bytes = new byte[4096];
        new Random().nextBytes(bytes);

        part.setContent(BlobProxy.generateProxy(bytes));
        part = this.partRepository.save(part); //2

        part.setCreateDateTime(LocalDateTime.now());
        part = this.partRepository.save(part); //3
    }
}

Only changed columns are included in the generated update statements in the lines //1 and //2. In the //3 line only the CREATE_DATETIME column is changed, but the CONTENT column is surprisingly also included in the update statement.

org.hibernate.SQL : update part set part_number=?, version=? where id=? and version=? //1 
...
org.hibernate.SQL : update part set version=?, content=? where id=? and version=? //2
...
org.hibernate.SQL : update part set create_datetime=?, version=?, content=? where id=? and version=? //3

How to get rid of the unnecessary CONTENT column in the //3 update statement?

pom.xml

    <?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        ...
        <properties>
            <java.version>1.8</java.version>
        </properties>

        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>com.oracle.ojdbc</groupId>
                <artifactId>ojdbc8</artifactId>
                <version>12.2.0.1.0</version>
            </dependency>       
        </dependencies>
    </project>