master database only
sysusages contains one row for each disk allocation piece assigned to a database. Each database contains a specified number of database (logical) page numbers.
The create database command checks sysdevices and sysusages 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.
See “System tables that manage space allocation” in Chapter 21, “Creating and Managing User Databases” of the System Administration Guide: Volume 2 for more information on sysusages.
In Adaptive Server version 15.0 and later, the device
identification number is stored in the vdevno column
and not as part of the vstart column. As a
consequence, you may need to modify scripts and stored procedures
that determine the device identification number based on the earlier
schema.
The columns for sysusages are:
Name |
Datatype |
Description |
|---|---|---|
dbid |
smallint |
Database ID |
segmap |
int |
Bitmap of possible segment assignments |
lstart |
unsigned int |
First database (logical) page number |
size |
unsigned int |
Number of contiguous database (logical) pages |
vstart |
int |
Starting virtual page number |
unreservedpgs |
unsigned int |
Free space not part of an allocated extent |
crdate |
datetime null |
Creation date |
vdevno |
int |
Device identification number |
Unique clustered index on dbid, lstart
Unique nonclustered index on vdevno, vstart
