gen4: support added for ordering on vindex function

Signed-off-by: Harshit Gangal <[email protected]>

go/vt/vtgate/planbuilder/horizon_planning.go

@@ -259,11 +259,12 @@ func pushProjection(expr *sqlparser.AliasedExpr, plan logicalPlan, semTable *sem
 		}
 		return 0, false, vterrors.Errorf(vtrpcpb.Code_INTERNAL, "cannot push projections in ordered aggregates")
 	case *vindexFunc:
+		colsBefore := len(node.eVindexFunc.Cols)
 		i, err := node.SupplyProjection(expr, reuseCol)
 		if err != nil {
 			return 0, false, err
 		}
-		return i, true, nil
+		return i /* col added */, len(node.eVindexFunc.Cols) > colsBefore, nil
 	case *limit:
 		return pushProjection(expr, node.input, semTable, inner, reuseCol)
 	case *distinct:
@@ -629,9 +630,10 @@ func (hp *horizonPlanning) planOrderBy(ctx *planningContext, orderExprs []abstra
 		plan.input = newUnderlyingPlan
 		return plan, nil
 	case *simpleProjection:
-		return hp.createMemorySortPlan(ctx, plan, orderExprs)
+		return hp.createMemorySortPlan(ctx, plan, orderExprs, true)
 	case *vindexFunc:
-		return nil, semantics.Gen4NotSupportedF("unsupported: ordering on vindex func")
+		// This is evaluated at VTGate only, so weight_string function cannot be used.
+		return hp.createMemorySortPlan(ctx, plan, orderExprs /* useWeightStr */, false)
 	default:
 		return nil, vterrors.Errorf(vtrpcpb.Code_UNIMPLEMENTED, "ordering on complex query %T", plan)
 	}
@@ -760,7 +762,7 @@ func (hp *horizonPlanning) planOrderByForJoin(ctx *planningContext, orderExprs [
 		plan.Left = newLeft
 		return plan, nil
 	}
-	sortPlan, err := hp.createMemorySortPlan(ctx, plan, orderExprs)
+	sortPlan, err := hp.createMemorySortPlan(ctx, plan, orderExprs, true)
 	if err != nil {
 		return nil, err
 	}
@@ -807,7 +809,7 @@ func findExprInOrderedAggr(plan *orderedAggregate, order abstract.OrderBy) (int,
 	return 0, 0, false
 }
 
-func (hp *horizonPlanning) createMemorySortPlan(ctx *planningContext, plan logicalPlan, orderExprs []abstract.OrderBy) (logicalPlan, error) {
+func (hp *horizonPlanning) createMemorySortPlan(ctx *planningContext, plan logicalPlan, orderExprs []abstract.OrderBy, useWeightStr bool) (logicalPlan, error) {
 	primitive := &engine.MemorySort{}
 	ms := &memorySort{
 		resultsBuilder: resultsBuilder{
@@ -819,7 +821,11 @@ func (hp *horizonPlanning) createMemorySortPlan(ctx *planningContext, plan logic
 	}
 
 	for _, order := range orderExprs {
-		offset, weightStringOffset, added, err := wrapAndPushExpr(order.Inner.Expr, order.WeightStrExpr, plan, ctx.semTable)
+		wsExpr := order.WeightStrExpr
+		if !useWeightStr {
+			wsExpr = nil
+		}
+		offset, weightStringOffset, added, err := wrapAndPushExpr(order.Inner.Expr, wsExpr, plan, ctx.semTable)
 		if err != nil {
 			return nil, err
 		}

go/vt/vtgate/planbuilder/testdata/memory_sort_cases.txt

@@ -706,6 +706,7 @@ Gen4 plan same as above
     ]
   }
 }
+Gen4 plan same as above
 
 # unary expression
 "select a from user order by binary a desc"