JPA持续存在大斑点

Question

I'm trying to persist an Entity with a large blob file, and I got an "Out of Memory" error in the JBoss log.

I test with several configurations, but always get the same result. I'm using jBoss 6 and MySQL.

An example of this... Entity:

@Entity
@Table(name="ficheros")
public class Fichero implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(unique=true, nullable=false)
    private int idfichero;

    @Lob()
    @Column(nullable=false)
    private Blob fichero;

    public Fichero() {
    }

    public int getIdfichero() {
        return this.idfichero;
    }

    public void setIdfichero(int idfichero) {
        this.idfichero = idfichero;
    }

    public Blob getFichero() {
        return this.fichero;
    }

    public void setFichero(Blob fichero) {
        this.fichero = fichero;
    }   
}

The class:

public Integer insertaFichero(Fichero fich) {
    ficheroDAO.create(fich);

    return fich.getIdfichero();
}

Is there another way to do that?

Answer 1

The problem with this error is that the operating system cannot allocate more memory for the threadstack so it fails to instantiate a new thread. Probably it's not a JBoss issue. You have to reduce the amount of memory each thread uses. A fine size for JBoss threads is 128k or 256k.

You can look at this articles from JBoss documentation

https://community.jboss.org/wiki/OutOfMemoryExceptions?_sscc=t .

https://community.jboss.org/wiki/OutOfMemoryExceptionWhenCannotCreateThread .

See also the stackoverflow question: Safe thread stack size?

To reduce this memory amount, in linux I found the command:

ulimit -s 256