[hibernate-issues] [Hibernate-JIRA] Created: (HHH-3056) Exception with empty resultset in HQL query containing join fetch of collection
Exception with empty resultset in HQL query containing join fetch of collection
-------------------------------------------------------------------------------
Key: HHH-3056
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3056
Project: Hibernate3
Issue Type: Bug
Components: query-hql
Affects Versions: 3.2.5
Environment: Windows XP sp2, Java 1.6.03, Tomcat 5.5.25
Reporter: Tony Lin
Attachments: object.zip
When performing this query on the attached model:
select subset from com.alphait.domain.snomed.object.SubsetImpl as subset join fetch
subset.members as members left join fetch members.parent where subset.id = -1
We received the following exception:
org.hibernate.exception.GenericJDBCException: could not perform sequential read of results
(forward)
at
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.Loader.loadSequentialRowsForward(Loader.java:398)
at
org.hibernate.impl.FetchingScrollableResultsImpl.next(FetchingScrollableResultsImpl.java:55)
at
org.hibernate.impl.FetchingScrollableResultsImpl.first(FetchingScrollableResultsImpl.java:200)
...
Caused by: java.sql.SQLException: Illegal operation on empty result set.
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkRowPos(ResultSet.java:713)
at com.mysql.jdbc.ResultSet.getLong(ResultSet.java:2850)
at com.mysql.jdbc.ResultSet.getLong(ResultSet.java:2845)
at com.mysql.jdbc.ResultSet.getLong(ResultSet.java:2960)
at org.hibernate.type.LongType.get(LongType.java:28)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:163)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:154)
at org.hibernate.loader.Loader.getKeyFromResultSet(Loader.java:1097)
at org.hibernate.loader.Loader.loadSequentialRowsForward(Loader.java:387)
After investigating the source code, we found two places are problematic:
1. org.hibernate.loader.Loader's loadSequentialRowsForward method:
if (resultSet.isAfterLast() ) {
// don't even bother trying to read further
return null;
}
if (resultSet.isBeforeFirst() ) {
resultSet.next();
}
Both isBeforeFirst(), and isAfterLast() returnd false if the resultset is empty, so the
code after these statements are executed before next() is called. we added the following
lines to fix this problem:
if (resultSet.getRow() < 1) {
return null;
}
2. In org.hibernate.impl.FetchingScrollableResultsImpl's next() method, it aways
returns true unless maxPosition is set. Should it be something like the following?
Object row = getLoader().loadSequentialRowsForward(
getResultSet(),
getSession(),
getQueryParameters(),
false
);
if (row == null) {
return false;
}
.....
We have not set scroll with other position yet.
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://opensource.atlassian.com/projects/hibernate/secure/Administrators....
-
For more information on JIRA, see: http://www.atlassian.com/software/jira