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
* @param rsMeta
	 */
	GroupCalculationUtil(BaseQuery query, IResultClass rsMeta,
			ResultSetPopulator resultPopoulator)
	{
		this.query = query;
		this.rsMeta = rsMeta;
		groupInformationUtil = new GroupInformationUtil( this );
		this.resultPopoulator = resultPopoulator;
	}
	/**
	 * @param inputStream
	 * @param rsMeta
	 * @param rsCache
	 * @throws DataException
	 */
	GroupCalculationUtil( InputStream inputStream, IResultClass rsMeta,
			ResultSetCache rsCache ) throws DataException
	{
		try
		{
			this.groupInformationUtil.readGroupsFromStream( inputStream );
		}
		catch ( IOException e )
		{
			throw new DataException( ResourceConstants.RD_LOAD_ERROR,
					e,
					"Group Info" );
		}
		this.rsMeta = rsMeta;