Hibernate returns last row n times

Hibernate ORM
1

Hi!
I am using hibernate core 6.0.0.Alpha6, and mysql-connector 8.0.22. DB MySql org.hibernate.dialect.MySQLDialect. My problem occurs on previous release too.

Running a simple SQL query on a single table, no join, returns only last record for n times, where n is the correct records number.

HQL Query

 SELECT ig.id, ig.codice 
    FROM ImpiantiGestitiDto as ig 
    where ig.idPalestra='6' order by ig.id";

Schema: id=integer idPalestra=integer codice=varchar(6) ImpiantiGestitiDto=Dto

This is my code. I don’t use loop.

 Query<Object> query = session.createQuery(hql);
 result = query.getResultList();

The mysql-connector run the query succesfully:
Output on getResultList(); Wrong!

[[10,“000.03”],[10,“000.03”],[10,“000.03”],[10,“000.03”]]

I think the problem occurs in: -org.hibernate.sql.results.spi package; -class ListResultsConsumer; -method Consume.

in following loop, results.add(row) ; instructions occurs the error. Why occurs the problem? Can you help me? Thank you!

while (rowProcessingState.next()) {     
    final R row = rowReader.readRow( rowProcessingState, processingOptions );    
    boolean add = true;     
    if ( uniqueRows ) {         
       if ( results.contains( row ) ) { 
        add = false;        
       }
    }   
    if ( add ) {        
       results.add( row );  
    }   
    rowProcessingState.finishRowProcessing(); 
}

Using the query “FROM ImpiantiGestitiDto where idPalestra=‘6’ order by id” it’s works.

Using the query “SELECT id, codice FROM ImpiantiGestitiDto where idPalestra=‘6’ order by id” does not work.

I have to use the second query because the table ImpiantiGestitiDto is joined to another table and I have to use the WHERE clause.

Thanks for your answer.

2

I’m not sure I can follow. Can you show the entity mapping? If id or codice are not unique, you will obviously get multiple seemingly duplicate result rows.

3

Id is an autoincrement on my MYSQL DB
Codice has different value on records.
Using the query “FROM ImpiantiGestitiDto where idPalestra=‘6’ order by id” it’s works.

This is the ID entity class…
package com.etabeta.dto;

import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
public abstract class IdDto {

@Id 
@GeneratedValue(strategy = javax.persistence.GenerationType.IDENTITY )  
@Column(name = "id", updatable = false, nullable = false)
private int id;	


public int getId() {
	return id;
}

public void setId(int id) {
	this.id = id;
}

}

This is a Codice Entity class…
package com.etabeta.dto;

import javax.persistence.Column;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
public abstract class CodiceDto extends IdDto {

@Column(name = "codice")
private String codice;

public String getCodice() {
	return codice;
}

public void setCodice(String codice) {
	this.codice = codice;
}

}

4

Do you have a primary key constraint on the table?

5

Yes. Primary Btree Autoincrement

6

This might be an issue in Hibernate 6. As you might have noticed, Hibernate 6 is still in an Alpha state which means there might still be bugs. Please try using Hibernate 5.4. e.g.

<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-core</artifactId>
  <version>5.4.23.Final</version>
</dependency>
7

Does not works.

JDBC returns this:
StandardRowReader - —Processing Row—
results - Extracted JDBC value [0] - [1]
results - Extracted JDBC value [1] - [000.00]
StandardRowReader - —Processing Row—
results - Extracted JDBC value [0] - [2]
results - Extracted JDBC value [1] - [000.01]
StandardRowReader - —Processing Row—
results - Extracted JDBC value [0] - [3]
results - Extracted JDBC value [1] - [000.02]
StandardRowReader - —Processing Row—
results - Extracted JDBC value [0] - [4]
results - Extracted JDBC value [1] - [000.03]

Hibernate returns this:
[[4,“000.03”],[4,“000.03”],[4,“000.03”],[4,“000.03”]]

8

Unless you are messing with the result somehow, this makes no sense. Could you please create a test case that reproduces this issue so that we can take a deeper look?

9

I send you my test code with configuration.

Thank you for your answer.
You can download from my drive the TestCase.zip.

-With IMPIANTI_GESTITI.sql you can import the table on mysql db.

-EntityMapping.zip contains the table hibernate mapping.
ImpiantiGestitiDto extends IdPalestraCodiceDto
IdPalestraCodiceDto extends CodiceDto
CodiceDto extends IdDto

-hibernate.cfg.xml is the hibernate configuration file

  • I run follow query:
    String hql = “SELECT id, codice FROM ImpiantiGestitiDto where idPalestra=‘6’ order by id”;
    Query query = session.createQuery(hql);
    result = query.list();
    query.list(); returns the last record for 4 times.

  • I run follow query:
    String hql = “FROM ImpiantiGestitiDto where idPalestra=‘6’ order by id”
    Query query = session.createQuery(hql);
    result = query.list();
    query.list(); returns the correct records

10

The attachments weren’t properly sent. Please fork the repository https://github.com/hibernate/hibernate-test-case-templates and create a test case with this template: https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-5/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java

You can then either send me the link to a pull request or to your fork so I can take a look.