Bug 147101 Report generation performance is sluggish
The overall performance of report generation appears to be quite sluggish. Here are numbers that we have measured using ORACLE as a DB. We use ORACLE 10g w/ojdbc14.jar thin driver. select rownum, datetime_id, another_id, text from ( select max(datetime_id) as datetime_id, another_id, text from some_oracle_schema.sample_table where text < 'c%' group by another_id, text ) Query resulting in 8465 rows Using PL/SQL developer: ----------------------- Execution: approx 1 second Iterating through all rows via PL/SQL developer UI: 10 seconds BIRT: ----- Preview page (via dataset editor): shows all 8465 rows in 53 seconds Preview tab (in the designer): shows all 8465 rows in 79 seconds Generation of rptdocument from rptdesign using API: 55 seconds
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/transform/group/GroupCalculationUtil.java
{
				if ( ( (GroupBoundaryInfo) groupArray[i].get( j ) ).isAccpted( ) )
				{
					result[i].add( groupArray[i].get( j ) );
				}
			}
		}
		return result;
	}
	/**
	 * 
	 * @return
	 */
	GroupBy[] getGroupDefn( )
	{
		return this.groupDefs;
	}
	ResultSetCache getResultSetCache( )
	{
		return this.smartCache;
	}
	/**
	 * Performs data transforms and starts the iterator
	 */
	public void initGroupSpec( ) throws DataException
	{
		
		IQuery.GroupSpec[] groupSpecs = query.getGrouping( );
		if ( groupSpecs != null )
		{