Is any way to optimize MDX query like this (this example is based on
Foodmart2000 sales cube) :

with set [oneperiod] as '{[Time].[1997].[Q3].[7]}'
set [secondperiod] as '{[Time].[1997].[Q2].[4]:[Time].[1997].[Q2].[5]}'
set [thirdperiod] as '{[Time].[1997].[Q2]:[Time].[1997].[Q4]}'
Member [Measures].[Unit_Sales_one_period] as
'sum([oneperiod],[Measures].[Unit Sales])'
Member [Measures].[Store_Sales_one_period] as
'sum([oneperiod],[Measures].[Store Sales])'
Member [Measures].[Unit_Sales_second_period] as
'sum([secondperiod],[Measures].[Unit Sales])'
Member [Measures].[Store_Sales_second_period] as
'sum([secondperiod],[Measures].[Store Sales])'
Member [Measures].[Unit_Sales_third_period] as
'sum([thirdperiod],[Measures].[Unit Sales])'
Member [Measures].[Store_Sales_third_period] as
'sum([thirdperiod],[Measures].[Store Sales])'

Select non empty nonemptycrossjoin(
Descendants([Store].[All Stores],[Store].[Store City])},
{Descendants([Product].[All Products],[Product].[Brand Name])}) on rows,
{[Measures].[Unit_Sales_one_period],[Measures].[Store_Sales_one_period],
[Measures].[Unit_Sales_second_period],[Measures].[Store_Sales_second_period],
[Measures].[Unit_Sales_third_period],[Measures].[Store_Sales_third_period]}
on columns from Sales

We have similiar solution and with some query parameters it takes long time