This sample output is printed for each nonclustered index, a clustered index on a data-only-locked table, and for a clustered index for an all-pages locked table. Information for clustered indexes on allpages-locked tables is reported as part of the table statistics. Table 2-3 describes the output.
Statistics for index: "title_id_ix" (nonclustered) Index column list: "title_id" Leaf count: 45 Empty leaf page count: 0 Data page CR count: 4952.0000000000000000 Index page CR count: 6.0000000000000000 Data row CR count: 4989.0000000000000000 First extent leaf pages: 0 Leaf row size: 17.8905999999999992 Index height: 1 Derived statistics: Data page cluster ratio: 0.0075819672131148 Index page cluster ratio: 1.0000000000000000 Data row cluster ratio: 0.0026634382566586
Parallel join degree, Unused page count, and OAM page count, which are not included in this sample, appear only for all-pages locked tables with a clustered index.
Row label |
Information provided |
---|---|
Statistics for index |
Index name and type. |
Index column list |
List of columns in the index. |
Leaf count |
Number of leaf-level pages in the index. |
Empty leaf page count |
Number of empty leaf pages in the index. |
Data page CR count |
A counter used to compute the data page cluster ratio for accessing a table using the index. |
Index page CR count |
A counter used to compute the index page cluster ratio. |
Data row CR count |
A counter used to compute the data row cluster ratio |
First extent leaf pages |
The number of leaf pages in the index stored in the first extent in an allocation unit. These pages need to be read using 2K I/O, rather than large I/O. This information is maintained only for indexes on data-only-locked tables. |
Leaf row size |
Average size of a leaf-level row in the index. This value is only updated by update statistics, create index, and alter table...lock. |
Index height |
Height of the index, not counting the leaf level. This row is included in the table-level output only for clustered indexes on allpages-locked tables. For all other indexes, the index height appears in the index-level output. This value does not apply to heap tables. |