Contains one row for each disk-allocation piece assigned to a database. Each database contains a specified number of database (logical) page numbers. Each disk piece includes segments 0 and 1.
When the CREATE DATABASE statement is executed, SQL Server scans the disk(s) to find available disk-allocation pieces. One or more contiguous disk-allocation pieces are assigned to the database, and the mapping is recorded in sysusages.
| Column | Datatype | Description |
|---|---|---|
| dbid | smallint | Database ID |
| segmap | int | Bitmap of possible segment assignments |
| lstart | int | First database (logical) page number |
| size | int | Number of contiguous database (logical) pages |
| vstart | int | Starting virtual page number |
sysusages clustered, unique on dbid, lstart
ncsysusages nonclustered, unique on vstart
| sp_addsegment | sp_dropsegment | sp_helpsegment |
| sp_databases | sp_extendsegment | sp_logdevice |
| sp_dbinstall | sp_helpdb | sp_remove |
| sp_devoption | sp_helplog | sp_spaceused |
| sp_dropdevice |