【IT168技术文档】

/**//*Author Hobbylu*/
/**//*Reference from sybase procedures*/
/**//*2005-07-01*/
create procedure sp_helpsegment_me
@segname varchar(30) = NULL /**//* segment name */
as
declare @segbit         int,    /**//* this is the bit version of the segment # */
@segment        int,    /**//* the segment number of the segment */
@free_pages     int,    /**//* unused pages in segment */
@factor         float,  /**//* conversion factor to convert to MB */
@clr_pages int, /**//* Space reserved for CLRs */
@total_pages int, /**//* total allocatable log space */
@used_pages int, /**//* allocated log space */
@ismixedlog int /**//* mixed log & data database ? */
if @@trancount = 0
begin
set chained off
end
set transaction isolation level 1
set nocount on
/**//*
**  If no segment name given, get 'em all.
*/
if @segname is null
begin

--Adaptive Server has expanded all '*' elements in the following statement 
select syssegments.segment, syssegments.name, syssegments.status
from syssegments order by segment
return (0)
end
/**//*
**  Make sure the segment exists
*/
if not exists (select *
from syssegments
where name = @segname)
begin
/**//* 17520, "There is no such segment as '%1!'." */
raiserror 17520, @segname
return (1)
end
/**//*
**  Show the syssegment entry, then the fragments and size it is on,
**  then any dependent objects in the database.
*/
--Adaptive Server has expanded all '*' elements in the following statement 
select syssegments.segment, syssegments.name, syssegments.status
from syssegments
where name = @segname
/**//*
**  Set the bit position for the segment.
*/
select @segment = segment
from syssegments
where name = @segname
/**//*
**  Now set the segments on @devname sysusages.
*/
if (@segment < 31)
select @segbit = power(2, @segment)
else
/**//*
**  Since this is segment 31, power(2, 31) will overflow
**  since segmap is an int.  We'll grab the machine-dependent
**  bit mask from spt_values to set the right bit.
*/
select @segbit = low
from master.dbo.spt_values
where type = "E"
and number = 2
/**//*
** Get factor for conversion of pages to megabytes from spt_values
*/
select @factor = convert(float, low) / 1048576.0
        from master.dbo.spt_values
        where number = 1 and type = "E"
select @total_pages = sum(u.size)
from master.dbo.sysusages u
where u.segmap & @segbit = @segbit
and u.dbid = db_id()
select @ismixedlog = status2 & 32768
from master.dbo.sysdatabases where dbid = db_id()
/**//*
** Select the sizes of the segments
*/
if (@segbit = 4)
begin
    select device = d.name,
size = convert(varchar(20), round((sum(u.size) * @factor), 0)) + "MB"
from master.dbo.sysusages u, master.dbo.sysdevices d
    where u.segmap & @segbit = @segbit
and u.dbid = db_id()
and d.status & 2 = 2
and u.vstart between d.low and d.high
    group by d.name order by d.name
    select @clr_pages = lct_admin("reserved_for_rollbacks", db_id())
    select @free_pages = lct_admin("logsegment_freepages", db_id())
- @clr_pages
    select free_pages = @free_pages
    if(@ismixedlog = 32768)
    begin
/**//*
** For a mixed log and data database, we cannot
** deduce the log used space from the total space
** as it is mixed with data. So we take the expensive
** way by scanning syslogs.
*/
select @used_pages = lct_admin("num_logpages", db_id())
/**//* Account allocation pages as used pages */
select @used_pages = @used_pages + (@total_pages / 256)
    end
    else
    begin
/**//* Dedicated log database */
select @used_pages = @total_pages - @free_pages
   - @clr_pages
    end
end
else
begin
    select device = d.name,
size = convert(varchar(20), round((sum(u.size) * @factor), 0)) + "MB",
free_pages = sum(curunreservedpgs(db_id(), u.lstart, u.unreservedpgs))
from master.dbo.sysusages u, master.dbo.sysdevices d
            where u.segmap & @segbit = @segbit
and u.dbid = db_id()
and d.status & 2 = 2
and u.vstart between d.low and d.high
    group by d.name order by d.name
    select @free_pages = sum(curunreservedpgs(db_id(), u.lstart, u.unreservedpgs))
from master.dbo.sysusages u
    where u.segmap & @segbit = @segbit
and u.dbid = db_id()
    select @used_pages = @total_pages - @free_pages
    select @clr_pages = 0
end
/**//*
** Select the dependent objects
*/

/**//*
** Print total_size, total_pages, free_pages, used_pages and reserved_pages
*/
select total_size = convert(varchar(15),
round(@total_pages * @factor, 0)) + "MB",
total_pages = convert(char(15), @total_pages),
free_pages = convert(char(15), @free_pages),
used_pages = convert(char(15), @used_pages),
reserved_pages = convert(char(15), @clr_pages)