=== modified file 'dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/DataQueryParams.java'
--- dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/DataQueryParams.java	2013-03-08 16:18:21 +0000
+++ dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/DataQueryParams.java	2013-03-09 12:34:00 +0000
@@ -142,7 +142,7 @@
     }
     
     /**
-     * Creates a mapping between the dimension names and the filter dimensions.
+     * Creates a mapping between dimension identifiers and filter dimensions.
      */
     public ListMap<String, Dimension> getDimensionFilterMap()
     {

=== modified file 'dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/data/DefaultQueryPlanner.java'
--- dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/data/DefaultQueryPlanner.java	2013-03-08 16:18:21 +0000
+++ dhis-2/dhis-services/dhis-service-analytics/src/main/java/org/hisp/dhis/analytics/data/DefaultQueryPlanner.java	2013-03-09 12:34:00 +0000
@@ -200,6 +200,17 @@
         }
 
         // ---------------------------------------------------------------------
+        // Group by data set
+        // ---------------------------------------------------------------------
+        
+        queries = splitByDimension( queries, DataQueryParams.DATASET_DIM_ID, optimalQueries );
+
+        if ( queries.size() >= optimalQueries )
+        {
+            return queries;
+        }
+
+        // ---------------------------------------------------------------------
         // Group by organisation unit
         // ---------------------------------------------------------------------
         

=== modified file 'dhis-2/dhis-services/dhis-service-analytics/src/test/java/org/hisp/dhis/analytics/data/QueryPlannerTest.java'
--- dhis-2/dhis-services/dhis-service-analytics/src/test/java/org/hisp/dhis/analytics/data/QueryPlannerTest.java	2013-02-26 18:33:01 +0000
+++ dhis-2/dhis-services/dhis-service-analytics/src/test/java/org/hisp/dhis/analytics/data/QueryPlannerTest.java	2013-03-09 12:34:00 +0000
@@ -54,11 +54,14 @@
 import org.hisp.dhis.dataelement.DataElementCategoryService;
 import org.hisp.dhis.dataelement.DataElementOperand;
 import org.hisp.dhis.dataelement.DataElementService;
+import org.hisp.dhis.dataset.DataSet;
+import org.hisp.dhis.dataset.DataSetService;
 import org.hisp.dhis.indicator.Indicator;
 import org.hisp.dhis.indicator.IndicatorService;
 import org.hisp.dhis.organisationunit.OrganisationUnit;
 import org.hisp.dhis.organisationunit.OrganisationUnitService;
 import org.hisp.dhis.period.Cal;
+import org.hisp.dhis.period.MonthlyPeriodType;
 import org.hisp.dhis.period.Period;
 import org.hisp.dhis.period.PeriodType;
 import org.hisp.dhis.period.QuarterlyPeriodType;
@@ -77,6 +80,9 @@
     private DataElementService dataElementService;
     
     @Autowired
+    private DataSetService dataSetService;
+    
+    @Autowired
     private DataElementCategoryService categoryService;
     
     @Autowired
@@ -96,6 +102,11 @@
     private DataElement deC;
     private DataElement deD;
     
+    private DataSet dsA;
+    private DataSet dsB;
+    private DataSet dsC;
+    private DataSet dsD;
+        
     private DataElementCategoryOptionCombo coc;
     
     private OrganisationUnit ouA;
@@ -109,6 +120,8 @@
     @Override
     public void setUpTest()
     {
+        PeriodType pt = new MonthlyPeriodType();
+        
         inA = createIndicator( 'A', null );
         
         indicatorService.addIndicator( inA );
@@ -123,6 +136,16 @@
         dataElementService.addDataElement( deC );
         dataElementService.addDataElement( deD );
         
+        dsA = createDataSet( 'A', pt );
+        dsB = createDataSet( 'B', pt );
+        dsC = createDataSet( 'C', pt );
+        dsD = createDataSet( 'D', pt );
+        
+        dataSetService.addDataSet( dsA );
+        dataSetService.addDataSet( dsB );
+        dataSetService.addDataSet( dsC );
+        dataSetService.addDataSet( dsD );
+        
         coc = categoryService.getDefaultDataElementCategoryOptionCombo();
         
         ouA = createOrganisationUnit( 'A' );
@@ -555,6 +578,31 @@
         
         queryPlanner.planQuery( params, 4, ANALYTICS_TABLE_NAME );
     }
+
+    /**
+     * Query spans 2 partitions. Splits in 2 queries for each partition, then
+     * splits in 2 queries on data sets to satisfy optimal for a total 
+     * of 4 queries.
+     */
+    @Test
+    public void planQueryK()
+    {
+        DataQueryParams params = new DataQueryParams();
+        params.setDataSets( getList( dsA, dsB, dsC, dsD ) );
+        params.setOrganisationUnits( getList( ouA, ouB, ouC, ouD, ouE ) );
+        params.setPeriods( getList( createPeriod( "2000Q1" ), createPeriod( "2000Q2" ), createPeriod( "2000Q3" ), createPeriod( "2000Q4" ), createPeriod(  "2001Q1" ), createPeriod( "2001Q2" ) ) );
+        
+        List<DataQueryParams> queries = queryPlanner.planQuery( params, 4, ANALYTICS_TABLE_NAME );
+        
+        assertEquals( 4, queries.size() );
+        
+        for ( DataQueryParams query : queries )
+        {
+            assertTrue( samePeriodType( query.getPeriods() ) );
+            assertTrue( samePartition( query.getPeriods() ) );
+            assertDimensionNameNotNull( query );
+        }
+    }
     
     // -------------------------------------------------------------------------
     // Supportive methods