[hibernate-issues] [Hibernate-JIRA] Created: (HHH-4618) Support pagination: total rows ignore limit

[Dave (JIRA)]

Support pagination: total rows ignore limit
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                 Key: HHH-4618
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4618
             Project: Hibernate Core
          Issue Type: New Feature
          Components: core
         Environment: JBoss 5.1.0GA
            Reporter: Dave


Limit is used for pagination, but total number of rows must be known to calculate page count.
Currently we have to use two queries:

1. select * from Student where age<30 limit 20;
2. select count(*) from Student where age<30;

For complex query with joins/huge tables, it can be a performance issue.

For Criteria API query with group by, there is no way to get row count, for example

criteria.setProjection(Projection.projectionList().add(Projections.groupProperty("name")).add(Projections.sum(score)));
Currently there is no way to get row count of this query using Criteria API.

For MYSQL, SQL_CALC_FOUND_ROWS and FOUND_ROWS() are used to get row count ignoring limit.

Pagination is used for all web application. Hibernate should support it in HQL and Criteria API.




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