// SetSystemVar sets system variable and updates SessionVars states.
func SetSystemVar(vars *variable.SessionVars, name string, value types.Datum) error {
name = strings.ToLower(name)
if value.IsNull() {
if name != variable.CharacterSetResults {
return variable.ErrCantSetToNull
}
delete(vars.Systems, name)
return nil
}
sVal, err := value.ToString()
if err != nil {
return errors.Trace(err)
}
switch name {
case variable.SQLModeVar:
sVal = strings.ToUpper(sVal)
if strings.Contains(sVal, "STRICT_TRANS_TABLES") || strings.Contains(sVal, "STRICT_ALL_TABLES") {
vars.StrictSQLMode = true
} else {
vars.StrictSQLMode = false
}
case variable.TiDBSnapshot:
err = setSnapshotTS(vars, sVal)
if err != nil {
return errors.Trace(err)
}
case variable.AutocommitVar:
isAutocommit := strings.EqualFold(sVal, "ON") || sVal == "1"
vars.SetStatusFlag(mysql.ServerStatusAutocommit, isAutocommit)
case variable.TiDBSkipConstraintCheck:
vars.SkipConstraintCheck = (sVal == "1")
}
vars.Systems[name] = sVal
return nil
}
func setSnapshotTS(s *variable.SessionVars, sVal string) error {
if sVal == "" {
s.SnapshotTS = 0
return nil
}
t, err := types.ParseTime(sVal, mysql.TypeTimestamp, types.MaxFsp)
if err != nil {
return errors.Trace(err)
}
t1, err := t.Time.GoTime()
ts := (t1.UnixNano() / int64(time.Millisecond)) << epochShiftBits
s.SnapshotTS = uint64(ts)
return errors.Trace(err)
}