Statistics descriptor
An access method returns statistics to the UPDATE STATISTICS statement in a statistics descriptor, or MI_AM_ISTATS_DESC structure. The database server copies the separate values from the statistics descriptor to pertinent tables in the system catalog.
The following accessor functions set information in the
statistics descriptor.
| Accessor function | Value set |
|---|---|
| mi_istats_set2lval() | A pointer to the second largest key value in the index |
| mi_istats_set2sval() | A pointer to the second smallest key value in the index |
| mi_istats_setclust() | The degree of clustering A low number indicates fewer clusters and a high degree of clustering. |
| mi_istats_setnleaves() | The number of leaves in the index |
| mi_istats_setnlevels() | The number of levels in the index |
| mi_istats_setnunique() | The number of unique keys in the index |