DAX-查询计划

　2012-06-09 07:12:00　来源：WEB开发网　　　

核心提示： DAX-查询计划，有四个： DAX VertiPaq Logical Plan DAX VertiPaq Physical Plan DAX DirectQuery Algebrizer Tree DAX DirectQuery Logical Plan运算符类型：

DAX-查询计划，有四个：

DAX VertiPaq Logical Plan
DAX VertiPaq Physical Plan
DAX DirectQuery Algebrizer Tree
DAX DirectQuery Logical Plan

运算符类型：

Plan Type	Operator Type	Description
Logical Plan	ScaLogOp	Scalar Logical Operator Outputs a scalar value of type numeric, string, Boolean, etc.
Logical Plan	RelLogOp	Relational Logical Operator Outputs a table of columns and rows.
Physical Plan	LookupPhyOp	Lookup Physical Operator Given a current row as input, calculates and returns a scalar value.
Physical Plan	IterPhyOp	Iterator Physical Operator Given a current row as an optional input, returns a sequence of rows.

实际上，物理计划还有第三个： SPOOL，它是执行子树的内存结果节点。

共同属性：

1， LOGICAL PLAN - SCALOGOP

DEPENDONCOLS:

它是逻辑运算符依靠的查询树左边的列。用于确认MEASURE是否正确依靠行环境。

DATA TYPE:

6个类型，加 BLANK.

DOMINANTVALUE:

如果它是NONE，就是 DENSE，不是，就是 SPARSE。类似MDX 的 BLOCK AND CELL-BY-CELL MODE。

2，LOGICAL PLAN - RELLOGOP

DEPENDON\COLS:

同上。

RANGE OF COLUMN NUMBERS:

DAX 使用 BEGIN-COLUMN-NAME END-COLUMN-NAME。

REQUIREDCOLS:

它是 DEPENDONCOLS 和 RANGE COLUMNS 的合集。

3，PHYSICAL PLAN - LOOKUPPHYOP

LOOKUPCOLS:

遍历器提供的列用于计算单值。

DATA TYPE:

同上。

4，PHYSICAL PLAN - ITERPHYOP

LOOKUPCOLS:

同上。

ITERCOLS:

遍历器输出列。

一个特殊的属性： SPOOL_ITERONLY<>

它就是一个遍历器，从内存SPOOL中得到行。

VERTIPAQ 运算符

Logical Operators	Description	Example
Scan_Vertipaq	This RelLogOp is the foundation of all other Vertipaq logical operators. It represents a basic Vertipaq query that joins a root table with related tables following many-to-one relationships, determines which rows are retrieved by testing against Vertiscan predicates, and groups the resultset by output columns.	evaluate ‘Product’
GroupBy_Vertipaq	This RelLogOp renames columns and adds rollup columns to a Vertipaq query.	evaluate summarize(‘Product’, rollup(‘Product Category’[Product Category Name], ‘Product’[Product Name]))
Filter_Vertipaq	This RelLogOp adds a Verticalc predicate to a Vertipaq query.	evaluate filter('Product', right([Product Name], 4) = "Tire")
Sum_Vertipaq	This ScaLogOp adds a SUM aggregation to a Vertipaq query.	evaluate row("x", sum('Internet Sales'[Sales Amount]))
Min_Vertipaq	This ScaLogOp adds a MIN aggregation to a Vertipaq query.	evaluate row("x", min('Internet Sales'[Sales Amount]))
Max_Vertipaq	This ScaLogOp adds a MAX aggregation to a Vertipaq query.	evaluate row("x", max('Internet Sales'[Sales Amount]))
Count_Vertipaq	This ScaLogOp adds a COUNT aggregation to a Vertipaq query.	evaluate row("x", countrows('Internet Sales'))
DistinctCount_Vertipaq	This ScaLogOp adds a DISTINCTCOUNT aggregation to a Vertipaq query.	evaluate row("x", distinctcount('Internet Sales'[Due Date]))
Average_Vertipaq	This ScaLogOp adds an AVERAGE aggregation to a Vertipaq query.	evaluate row("x", average('Internet Sales'[Sales Amount]))
Stdev.S_Vertipaq	This ScaLogOp adds a STDEV.S aggregation to a Vertipaq query.	evaluate row("x", stdev.s('Internet Sales'[Sales Amount]))
Stdev.P_Vertipaq	This ScaLogOp adds a STDEV.P aggregation to a Vertipaq query.	evaluate row("x", stdev.p('Internet Sales'[Sales Amount]))
Var.S_Vertipaq	This ScaLogOp adds a VAR.S aggregation to a Vertipaq query.	evaluate row("x", var.s('Internet Sales'[Sales Amount]))
Var.P_Vertipaq	This ScaLogOp adds a VAR.P aggregation to a Vertipaq query.	evaluate row("x", var.p('Internet Sales'[Sales Amount]))
Physical Operators
VertipaqResult	This IterPhyOp iterates over the resultset returned by a Vertipaq query.	You can find this operator in the physical plan tree after running any of the above queries.