refactor: address review comments

Signed-off-by: Andres Taylor <[email protected]>

go/mysql/sqlerror/sql_error.go

@@ -244,7 +244,6 @@ var stateToMysqlCode = map[vterrors.State]mysqlCode{
 	vterrors.KillDeniedError:              {num: ERKillDenied, state: SSUnknownSQLState},
 	vterrors.BadNullError:                 {num: ERBadNullError, state: SSConstraintViolation},
 	vterrors.InvalidGroupFuncUse:          {num: ERInvalidGroupFuncUse, state: SSUnknownSQLState},
-	vterrors.AggregateMustPushDown:        {num: ERNotSupportedYet, state: SSUnknownSQLState},
 }
 
 func getStateToMySQLState(state vterrors.State) mysqlCode {

go/vt/vterrors/code.go

@@ -58,7 +58,6 @@ var (
 	VT03030 = errorWithState("VT03030", vtrpcpb.Code_INVALID_ARGUMENT, WrongValueCountOnRow, "lookup column count does not match value count with the row (columns, count): (%v, %d)", "The number of columns you want to insert do not match the number of columns of your SELECT query.")
 	VT03031 = errorWithoutState("VT03031", vtrpcpb.Code_INVALID_ARGUMENT, "EXPLAIN is only supported for single keyspace", "EXPLAIN has to be sent down as a single query to the underlying MySQL, and this is not possible if it uses tables from multiple keyspaces")
 	VT03032 = errorWithState("VT03032", vtrpcpb.Code_INVALID_ARGUMENT, NonUpdateableTable, "the target table %s of the UPDATE is not updatable", "You cannot update a table that is not a real MySQL table.")
-	VT03033 = errorWithState("VT03033", vtrpcpb.Code_INVALID_ARGUMENT, AggregateMustPushDown, "aggregate user-defined function %s must be pushed down to mysql", "The aggregate user-defined function must be pushed down to mysql and can't be evaluated on the vtgate. The query contains aggregation that can't be fully pushed down to MySQL.")
 
 	VT05001 = errorWithState("VT05001", vtrpcpb.Code_NOT_FOUND, DbDropExists, "cannot drop database '%s'; database does not exists", "The given database does not exist; Vitess cannot drop it.")
 	VT05002 = errorWithState("VT05002", vtrpcpb.Code_NOT_FOUND, BadDb, "cannot alter database '%s'; unknown database", "The given database does not exist; Vitess cannot alter it.")

go/vt/vterrors/state.go

@@ -49,7 +49,6 @@ const (
 	WrongArguments
 	BadNullError
 	InvalidGroupFuncUse
-	AggregateMustPushDown
 
 	// failed precondition
 	NoDB

go/vt/vtgate/planbuilder/operators/offset_planning.go

@@ -139,7 +139,8 @@ func addColumnsToInput(ctx *plancontext.PlanningContext, root Operator) Operator
 		for _, aggr := range aggrOp.Aggregations {
 			if aggr.OpCode == opcode.AggregateUDF {
 				// we don't support UDFs in aggregation if it's still above a route
-				panic(vterrors.VT03033(sqlparser.String(aggr.Original.Expr)))
+				message := fmt.Sprintf("Aggregate UDF %s must be pushed down to MySQL", sqlparser.String(aggr.Original.Expr))
+				panic(vterrors.VT12001(message))
 			}
 		}
 		return in, NoRewrite
@@ -154,8 +155,8 @@ func addColumnsToInput(ctx *plancontext.PlanningContext, root Operator) Operator
 	return TopDown(root, TableID, visitor, stopAtRoute)
 }
 
-// pullDistinctFromUNION will pull out the distinct from a union operator
-func pullDistinctFromUNION(_ *plancontext.PlanningContext, root Operator) Operator {
+// isolateDistinctFromUnion will pull out the distinct from a union operator
+func isolateDistinctFromUnion(_ *plancontext.PlanningContext, root Operator) Operator {
 	visitor := func(in Operator, _ semantics.TableSet, isRoot bool) (Operator, *ApplyResult) {
 		union, ok := in.(*Union)
 		if !ok || !union.distinct {

go/vt/vtgate/planbuilder/operators/phases.go

@@ -88,7 +88,7 @@ func (p Phase) shouldRun(s semantics.QuerySignature) bool {
 func (p Phase) act(ctx *plancontext.PlanningContext, op Operator) Operator {
 	switch p {
 	case pullDistinctFromUnion:
-		return pullDistinctFromUNION(ctx, op)
+		return isolateDistinctFromUnion(ctx, op)
 	case delegateAggregation:
 		return enableDelegateAggregation(ctx, op)
 	case addAggrOrdering:

go/vt/vtgate/planbuilder/plan_test.go

@@ -586,9 +586,7 @@ func TestOtherPlanningFromFile(t *testing.T) {
 
 func loadSchema(t testing.TB, filename string, setCollation bool) *vindexes.VSchema {
 	formal, err := vindexes.LoadFormal(locateFile(filename))
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	vschema := vindexes.BuildVSchema(formal, sqlparser.NewTestParser())
 	require.NoError(t, err)
 	for _, ks := range vschema.Keyspaces {

go/vt/vtgate/vindexes/vschema.go

@@ -425,7 +425,7 @@ func (vschema *VSchema) AddView(ksname, viewName, query string, parser *sqlparse
 	return nil
 }
 
-// AddTable adds a table to an existing keyspace in the VSchema.
+// AddUDF adds a UDF to an existing keyspace in the VSchema.
 // It's only used from tests.
 func (vschema *VSchema) AddUDF(ksname, udfName string) error {
 	ks, ok := vschema.Keyspaces[ksname]