// derivativeInterval returns the time interval for the one (and only) derivative func
func derivativeInterval(stmt *influxql.SelectStatement) (time.Duration, error) {
if len(stmt.FunctionCalls()[0].Args) == 2 {
return stmt.FunctionCalls()[0].Args[1].(*influxql.DurationLiteral).Val, nil
}
interval, err := stmt.GroupByInterval()
if err != nil {
return 0, err
}
if interval > 0 {
return interval, nil
}
return time.Second, nil
}
func (s *Shard) ValidateAggregateFieldsInStatement(measurementName string, stmt *influxql.SelectStatement) error {
s.mu.RLock()
defer s.mu.RUnlock()
validateType := func(aname, fname string, t influxql.DataType) error {
if t != influxql.Float && t != influxql.Integer {
return fmt.Errorf("aggregate '%s' requires numerical field values. Field '%s' is of type %s",
aname, fname, t)
}
return nil
}
m := s.measurementFields[measurementName]
if m == nil {
return fmt.Errorf("measurement not found: %s", measurementName)
}
// If a numerical aggregate is requested, ensure it is only performed on numeric data or on a
// nested aggregate on numeric data.
for _, a := range stmt.FunctionCalls() {
// Check for fields like `derivative(mean(value), 1d)`
var nested *influxql.Call = a
if fn, ok := nested.Args[0].(*influxql.Call); ok {
nested = fn
}
switch lit := nested.Args[0].(type) {
case *influxql.VarRef:
if IsNumeric(nested) {
f := m.Fields[lit.Val]
if err := validateType(a.Name, f.Name, f.Type); err != nil {
return err
}
}
case *influxql.Distinct:
if nested.Name != "count" {
return fmt.Errorf("aggregate call didn't contain a field %s", a.String())
}
if IsNumeric(nested) {
f := m.Fields[lit.Val]
if err := validateType(a.Name, f.Name, f.Type); err != nil {
return err
}
}
default:
return fmt.Errorf("aggregate call didn't contain a field %s", a.String())
}
}
return nil
}