func (this *builder) selectScan(keyspace datastore.Keyspace, node *algebra.KeyspaceTerm,
limit expression.Expression) (op plan.Operator, err error) {
keys := node.Keys()
if keys != nil {
switch keys := keys.(type) {
case *expression.ArrayConstruct:
this.maxParallelism = util.MaxInt(1, len(keys.Operands()))
case *algebra.NamedParameter, *algebra.PositionalParameter:
this.maxParallelism = 0
default:
this.maxParallelism = 1
}
return plan.NewKeyScan(keys), nil
}
this.maxParallelism = 0 // Use default parallelism for index scans
secondary, primary, err := this.buildScan(keyspace, node, limit)
if err != nil {
return nil, err
}
if secondary != nil {
return secondary, nil
} else {
return primary, nil
}
}
func (this *builder) VisitUpsert(stmt *algebra.Upsert) (interface{}, error) {
ksref := stmt.KeyspaceRef()
ksref.SetDefaultNamespace(this.namespace)
keyspace, err := this.getNameKeyspace(ksref.Namespace(), ksref.Keyspace())
if err != nil {
return nil, err
}
children := make([]plan.Operator, 0, 4)
if stmt.Values() != nil {
children = append(children, plan.NewValueScan(stmt.Values()))
this.maxParallelism = util.MaxInt(1, len(stmt.Values()))
} else if stmt.Select() != nil {
sel, err := stmt.Select().Accept(this)
if err != nil {
return nil, err
}
children = append(children, sel.(plan.Operator))
} else {
return nil, fmt.Errorf("UPSERT missing both VALUES and SELECT.")
}
subChildren := make([]plan.Operator, 0, 4)
subChildren = append(subChildren, plan.NewSendUpsert(keyspace, ksref.Alias(), stmt.Key(), stmt.Value()))
if stmt.Returning() != nil {
subChildren = append(subChildren, plan.NewInitialProject(stmt.Returning()), plan.NewFinalProject())
} else {
subChildren = append(subChildren, plan.NewDiscard())
}
parallel := plan.NewParallel(plan.NewSequence(subChildren...), this.maxParallelism)
children = append(children, parallel)
return plan.NewSequence(children...), nil
}