curunreservedpgs

Syntax

curunreservedpgs (dbid, lstart, unreservedpgs)

Parameters

• dbid – is the ID for a database. These are stored in the db_id column of sysdatabases.
• lstart – is the starting logical page number for the disk piece for which you are retrieving data. lstart uses an unsigned int datatype.
• unreservedpgs – is the default value curunreservedpgs returns if no in-memory data is available. unreservedpgs uses an unsigned int datatype.

Examples

• Example 1 – Returns the database name, device name, and the number of unreserved pages for each device fragment

  If a database is open, curunreservedpgs takes the value from memory. If it is not in use, the value is taken from the third parameter you specify in curunreservedpgs. In this example, the value comes from the unreservedpgs column in the sysusages table.

  select 

  (dbid), d.name,
      curunreservedpgs(dbid, lstart, unreservedpgs)
      from sysusages u, sysdevices d
  where u.vdevno=d.vdevno
  and d.status &2 = 2

                                  name
   ------------------------------ -------------------------- -----------
  master                          master                            1634
  tempdb                          master                             423
  model                           master                             423
  pubs2                           master                              72
  sybsystemdb                     master                             399
  sybsystemprocs                  master                            6577
  sybsyntax                       master                             359
  
  (7 rows affected)

• Example 2 – Displays the number of free pages on the segment for dbid starting on sysusages.lstart:

  select curunreservedpgs (dbid, sysusages.lstart, 0)

Usage

If a database is open, the value returned by curunreservedpgs is taken from memory. If it is not in use, the value is taken from the third parameter you specify in curunreservedpgs.

See also Transact-SQL Users Guide.

Standards

ANSI SQL – Compliance level: Transact-SQL extension.

Permissions

Any user can execute curunreservedpgs.