[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2207) Suggested fix for HQL - MySQL setMaxResults issue
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http://opensource.atlassian.com/projects/hibernate/browse/HHH-2207?page=c...
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Toby Moore commented on HHH-2207:
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Ah yes, after looking at the source a bit closer, it seems that the same problem is
replicated in another part of the code. The calling code expects the method to return how
many parameters were added, but instead it returns the index of the parameter passed in.
I've added another patch to this thread which fixes both problems for us.
This all seems to be related to the SQL dialects that have a limit clause at the end of
the statement, which is why we're finding these problems for MySQL.
Let me know if the patch works!
Suggested fix for HQL - MySQL setMaxResults issue
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Key: HHH-2207
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2207
Project: Hibernate3
Type: Bug
Components: query-hql
Versions: 3.2.0.ga
Environment: Hi 3.2.0.ga MySQL
Reporter: Toby Moore
Attachments: querloaderdiff.patch
Original Estimate: 0 minutes
Remaining: 0 minutes
Hi,
After some experimentation, we'd like to suggest an easy fix to a problem we
encountered.
When using HQL with the Hibernate 3 entity manager to limit the number of records
returned ( at the database level, via generated SQL, not in memory) we were getting an
exception due to the query builder trying to attach a parameter to the prepared statement
that was out of bounds :
by: java.sql.SQLException: Parameter index out of range (4 > number of parameters,
which is 3).
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:2556)
at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:2584)
at com.mysql.jdbc.PreparedStatement.setInt(PreparedStatement.java:2540)
at
com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.setInt(NewProxyPreparedStatement.java:677)
at org.hibernate.loader.Loader.bindLimitParameters(Loader.java:1616)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1560)
at org.hibernate.loader.Loader.doQuery(Loader.java:661)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.doList(Loader.java:2156)
... 10 more
On looking at the code in the method bindParameterValues in
org.hibernate.loader.hql.QueryLoader ( line 491 ) the method returns the next parameter
position that needs to be set, not the amount of parameters it has added, which is
expected in Loader.java on the line
col += bindParameterValues( st, queryParameters, col, session );
This causes the parameter count to get out of sync and thus throw the expcetion saying
that it can't add a parameter out of range.
A simple fix for this is to change the return line in QueryLoader to be
return position - startPosition;
which will return the amount of parameters this method added.
We've tested this on our mysql implementation and it works, and run the unit tests to
check that no extra errors are generated. If this seems like a good fix then i'll
submit it as a patch via the JIRA, but would like to hear any thoughts first?
Kind regards,
TobyM - MindCandyDesign London
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