为什么.CHILDREN比.MEMBERS慢？

Question

我有两个相同的查询。一个使用.CHILDREN检索成员，而其他人使用.MEMBERS。它们被应用于自然层次结构。我一直发现.MEMBERS通常比.CHILDREN更快地返回结果（有时快得多）。以下是我发现的MDX工作室的查询，消息和perfmon摘录具有最大差异。

查询1（使用.MEMBERS）

with set abc as
[Accident Cause].[Accident Cause Code].members

member measures.bcd as
sum(existing abc, [Measures].[Claim As Of - Count])

select {[Measures].[Claim As Of - Count], measures.bcd} on 0,
[Accident Cause].[Accident Cause Code].members on 1
from [aw cube]

--5 seconds

执行查询... 获取类型的对象：Microsoft.AnalysisServices.AdomdClient.CellSet 格式化。 单元格集由1126行和3列组成。 完成格式化。 执行完成

NON EMPTYs        : 0
Autoexists        : 0
EXISTINGs         : 1125
SE queries        : 0
Flat cache insert : 2
Cache hits        : 0
Cache misses      : 0
Cache inserts     : 0
Cache lookups     : 0
Memory Usage KB   : 4992

---

查询2（使用.CHILDREN）

with set abc as
[Accident Cause].[Accident Cause Code].children

member measures.bcd as
sum(existing abc, [Measures].[Claim As Of - Count])

select {[Measures].[Claim As Of - Count], measures.bcd} on 0,
[Accident Cause].[Accident Cause Code].children on 1
from [aw cube]

执行查询... 获取类型的对象：Microsoft.AnalysisServices.AdomdClient.CellSet 格式化。 单元格集由1125行和3列组成。 完成格式化。 执行完成

NON EMPTYs        : 0
Autoexists        : 0
EXISTINGs         : 1124
SE queries        : 0
Flat cache insert : 1124
Cache hits        : 0
Cache misses      : 0
Cache inserts     : 0
Cache lookups     : 0
Memory Usage KB   : 3744

--41 seconds

虽然我知道这些功能之间的概念差异，但我不明白为什么性能可能会有这么大的变化。

编辑 - 冒险作品的结果

with set abc as
[Geography].[City].members

member measures.bcd as
sum(existing abc,[Measures].[Internet Sales Amount])

select {[Measures].[Internet Sales Amount], measures.bcd} on 0,
[Geography].[City].members on 1
from [Adventure Works]


/*
Time              : 503 ms
Calc covers       : 0
Cells calculated  : 2938
Sonar subcubes    : 1186
NON EMPTYs        : 0
Autoexists        : 0
EXISTINGs         : 588
SE queries        : 2
Flat cache insert : 1
Cache hits        : 1180
Cache misses      : 0
Cache inserts     : 0
Cache lookups     : 1180
Memory Usage KB   : 0
*/

with set abc as
[Geography].[City].children

member measures.bcd as
sum(existing abc,[Measures].[Internet Sales Amount])

select {[Measures].[Internet Sales Amount], measures.bcd} on 0,
[Geography].[City].children on 1
from [Adventure Works]



/*
Time              : 843 ms
Calc covers       : 0
Cells calculated  : 1174
Sonar subcubes    : 589
NON EMPTYs        : 0
Autoexists        : 0
EXISTINGs         : 587
SE queries        : 588
Flat cache insert : 0
Cache hits        : 1176
Cache misses      : 0
Cache inserts     : 0
Cache lookups     : 1176
Memory Usage KB   : 28912        
*/