Databases Reference
In-Depth Information
partition called Slice. This property allows you to specify an MDX expression which
indicates the slice on a hierarchy (a member or a group of members in that hier-
archy) that uniquely identifies the data within the partition. When the Slice property
is specified then Analysis Services sends ROLAP queries to partitions only if the
MDX query requested is expected to retrieve results from those partitions. If the
Slice property is not specified then by default Analysis Services assumes data can
be contained in that partition for any MDX query.
Assume you have partitioned the data by time, 5 partitions for 5 years.
Typically, most of the queries will involve only the current year. In this
case there is no need to send 5 queries, of which 4 will return no data.
By setting the slice property indicating that the 2001 partition contains
data for year 2001, 2002 partition contains data for year 2002 and so
on, you provide a hint to Analysis Services so that it can optimize the
relational queries sent. The Slice property for a partition can be set in
BIDS or SSMS. For example, if you need to set a specific partition's
data for year 2004, you will provide the MDX expression for 2004 as
[Date].[Calendar].[Calendar Year].&[2004]. By default the value for the
slice property is set to null, which indicates to Analysis Services that this
specific partition can contain data for all the queries. The following steps
show how to set the slice property.
1. Deploy the sample Adventure Works DW project shipped with
SQL Server 2005 and ensure the database is processed. Connect
to the Adventure Works DW database using SSMS.
2. Navigate through the partitions of Internet Sales measure
group. Change the storage mode for all the partitions to ROLAP.
3. Right click on the Internet_Sales_2001 partition object and se-
lect Properties. Alternatively, you can double-click the partition,
which will bring up the property page of the partitions as shown
in
Figure 13-13
.
Search WWH ::
Custom Search