func getSessionStatusVar(ctx context.Context, sessionVars *variable.SessionVars,
globalVars variable.GlobalVarAccessor, name string) (string, error) {
sv, ok := sessionVars.StatusVars[name]
if ok {
return sv, nil
}
value, err := globalVars.GetGlobalStatusVar(ctx, name)
if err != nil && terror.UnknownStatusVar.Equal(err) {
return "", errors.Trace(err)
}
return value, nil
}
func (e *SimpleExec) getVarValue(v *ast.VariableAssignment, sysVar *variable.SysVar, globalVars variable.GlobalVarAccessor) (value types.Datum, err error) {
switch v.Value.(type) {
case *ast.DefaultExpr:
// To set a SESSION variable to the GLOBAL value or a GLOBAL value
// to the compiled-in MySQL default value, use the DEFAULT keyword.
// See http://dev.mysql.com/doc/refman/5.7/en/set-statement.html
if sysVar != nil {
value = types.NewStringDatum(sysVar.Value)
} else {
s, err1 := globalVars.GetGlobalSysVar(e.ctx, strings.ToLower(v.Name))
if err1 != nil {
return value, errors.Trace(err1)
}
value = types.NewStringDatum(s)
}
default:
value, err = evaluator.Eval(e.ctx, v.Value)
}
return value, errors.Trace(err)
}