The Physical Data Model - Microsoft SQL Server 2008 Analysis Services - page 353

Map Data Store Headers (.data.hdr) Map Data Store (.data) Map String Store (string.data)

Header for Segment 1 Segment 1 (64K Records) Page 1 (64K Bytes)

String 1 String 1

…
String K

Block 1
Page 1
Record 1

String 2
…

Header for Segment 2

Record 2
…
Record 256

String K

…

Page 2

Header for Segment N

Page 2

…

…

Page N

Page 16

Block 2

…

Block 16

Segment 2

…

Segment N

FIGURE 20.5 Map store is stored in three data structures: the map data store headers, the
map data store, and the map string store.

Map Stores for Related Attributes
Attribute relationships are stored in the map store. Each record in this store corresponds to
the DataID of an attribute member; each column in the store corresponds to an attribute
related to the current attribute. Because all the fields contain DataID s for the related
members, all the fields of the map store are 4-byte integer values, compressed on a per-
segment basis. The number of records in the map store is equivalent to the number of
members in the current attribute, and the ordinal position of the record is the same as the
DataID of the current member.