The mi_istats_setclust() accessor function
The mi_istats_setclust() function stores the degree of clustering for an index in the statistics descriptor.
Syntax
void mi_istats_setclust(MI_AM_ISTATS_DESC *istatsDesc,
mi_integer clustering)- istatsDesc
- Points to the statistics descriptor.
- clustering
- Specifies the degree of clustering, from number of pages to number of rows.
Usage
Call this function from am_stats. The database server places the value that this function sets in the clust column of the sysindices system catalog table.
Clustering specifies
the degree to which the rows are in the same order as the index. For
example, if the index references a table that is in page-size areas,
such as in a dbspace or sbspace, you can estimate clustering as follows:
- The lowest possible clustering value equals the number of pages that data occupies, or one cluster per page.
- The highest possible value (and least amount of clustering) equals the number of rows, or one cluster per entry.
Return values
None