Customer has a report they run that shows table space usage. (See query blelow).
Some of these tables are using very little space but have many GBs of unused space . For example the SavedReport table is using 1480KB but has 16461624 of unused space. Is there a way to free up this unused space?
declare @id int
declare @type character(2)
declare @pages int
declare @dbname sysname
declare @dbsize dec(15,0)
declare @bytesperpage dec(15,0)
declare @pagesperMB dec(15,0)
create table #spt_space
(
objid int null,
rows int null,
reserved dec(15) null,
data dec(15) null,
indexp dec(15) null,
unused dec(15) null
)
set nocount on
-- Create a cursor to loop through the user tables
declare c_tables cursor for
select id
from sysobjects
where xtype = 'U'
open c_tables
fetch next from c_tables
into @id
while @@fetch_status = 0
begin
/* Code from sp_spaceused */
insert into #spt_space (objid, reserved)
select objid = @id, sum(reserved)
from sysindexes
where indid in (0, 1, 255)
and id = @id
select @pages = sum(dpages)
from sysindexes
where indid < 2
and id = @id
select @pages = @pages + isnull(sum(used), 0)
from sysindexes
where indid = 255
and id = @id
update #spt_space
set data = @pages
where objid = @id
/* index: sum(used) where indid in (0, 1, 255) - data */
update #spt_space
set indexp = (select sum(used)
from sysindexes
where indid in (0, 1, 255)
and id = @id)
- data
where objid = @id
/* unused: sum(reserved) - sum(used) where indid in (0, 1, 255) */
update #spt_space
set unused = reserved
- (select sum(used)
from sysindexes
where indid in (0, 1, 255)
and id = @id)
where objid = @id
update #spt_space
set rows = i.rows
from sysindexes i
where i.indid < 2
and i.id = @id
and objid = @id
fetch next from c_tables
into @id
end
select top 50
Table_Name = (select left(name,25) from sysobjects where id = objid),
rows = convert(char(11), rows),
reserved_KB = ltrim(str(reserved * d.low / 1024.,15,0)),
data_KB = ltrim(str(data * d.low / 1024.,15,0)),
index_size_KB = ltrim(str(indexp * d.low / 1024.,15,0)),
unused_KB = ltrim(str(unused * d.low / 1024.,15,0))
from #spt_space, master.dbo.spt_values d
where d.number = 1
and d.type = 'E'
order by reserved desc
drop table #spt_space
close c_tables
deallocate c_tables
Answer
The “Rebuild Index Task” in a maintenance plan should shrink these tables automatically. However, if you have the “Keep index online while reindexing” checked in the Maintenace Plan, specific tables may NOT be reindexed due to locks. The recommendation is to make sure that “Keep index online while reindexing” is unchecked.
There isn’t a SQL Server shrink command to shrink just a table other than dbcc shrinkdatabase or dbcc shrinkfile which will shrink the entire database. However, dbcc INDEXDEFRAG <tablename> should defrag and shrink the table.