查明SQL Server表和模式空间使用情况

SQL Server数据库的管理员常常会头疼硬盘可用空间太少，往往需要编写很多查询来查明哪些表和模式占用了大量的硬盘空间，以便能够定期清理这些表和模式。本文将为大家阐述如何查询系统目录来确定磁盘空间的使用情况，可以帮助SQL Server数据库管理员识别占用最大空间的表和模式，以便将老旧的数据归档，将不需要的数据清除。本文所列脚本适用于SQL Server 2005和SQL Server 2008 CTP5。

　　步骤1：如图一所示，登录到SQL Server实例。

步骤2：确定你想要获得空间使用信息的数据库，导航到该数据库，如下所示(见图二)

　　Use AdventureWorks

　　go

步骤3.1：将下面的代码添加到查询窗口，并执行(见图三)。
　　begin try
SELECT
(row_number() over(order by a3.name, a2.name))%2 as l1,
a3.name AS [schemaname],
a2.name AS [tablename],
a1.rows as row_count,
(a1.reserved + ISNULL(a4.reserved,0))* 8 AS reserved,
a1.data * 8 AS data,
(CASE WHEN (a1.used + ISNULL(a4.used,0)) > a1.data THEN
   (a1.used + ISNULL(a4.used,0)) - a1.data ELSE 0 END) * 8 AS index_size,
(CASE WHEN (a1.reserved + ISNULL(a4.reserved,0)) > a1.used THEN
   (a1.reserved + ISNULL(a4.reserved,0)) - a1.used ELSE 0 END) * 8 AS unused
FROM
(SELECT
  ps.object_id,
  SUM (
   CASE
    WHEN (ps.index_id < 2) THEN row_count
    ELSE 0
   END
   ) AS [rows],
  SUM (ps.reserved_page_count) AS reserved,
  SUM (
   CASE
     WHEN (ps.index_id < 2) THEN
   (ps.in_row_data_page_count + ps.lob_used_page_count + ps.row_overflow_used_page_count)
     ELSE (ps.lob_used_page_count + ps.row_overflow_used_page_count)
   END
   ) AS data,
  SUM (ps.used_page_count) AS used
FROM sys.dm_db_partition_stats ps
GROUP BY ps.object_id) AS a1
LEFT OUTER JOIN
(SELECT
  it.parent_id,
  SUM(ps.reserved_page_count) AS reserved,
  SUM(ps.used_page_count) AS used
  FROM sys.dm_db_partition_stats ps
  INNER JOIN sys.internal_tables it ON (it.object_id = ps.object_id)
  WHERE it.internal_type IN (202,204)
  GROUP BY it.parent_id) AS a4 ON (a4.parent_id = a1.object_id)
INNER JOIN sys.all_objects a2  ON ( a1.object_id = a2.object_id )
INNER JOIN sys.schemas a3 ON (a2.schema_id = a3.schema_id)
WHERE a2.type <> \'S\' and a2.type <> \'IT\'
ORDER BY a3.name, a2.name
end try
begin catch
select
-100 as l1
, 1 as schemaname
,       ERROR_NUMBER() as tablename
,       ERROR_SEVERITY() as row_count
,       ERROR_STATE() as reserved
,       ERROR_MESSAGE() as data
,       1 as index_size
,   1 as unused
end catch

执行上述代码的时候，我们可以看到表空间使用报告(见图四)。

　步骤3.2：上述脚本可进行一定修改，使用SUM、COUNT函数并通过从句进行分组，以显示模式空间的使用情况。将以下代码添加到查询窗口，并运行(见图五)。
　　begin try
SELECT
(row_number() over(order by a3.name, a2.name))%2 as l1,
a3.name AS [schemaname],
count(a2.name ) as NumberOftables,
sum(a1.rows) as row_count,
sum((a1.reserved + ISNULL(a4.reserved,0))* 8) AS reserved,
sum(a1.data * 8) AS data,
sum((CASE WHEN (a1.used + ISNULL(a4.used,0)) > a1.data THEN
   (a1.used + ISNULL(a4.used,0)) - a1.data ELSE 0 END) * 8 )AS index_size,
sum((CASE WHEN (a1.reserved + ISNULL(a4.reserved,0)) > a1.used THEN
   (a1.reserved + ISNULL(a4.reserved,0)) - a1.used ELSE 0 END) * 8) AS unused
FROM
(SELECT
  ps.object_id,
  SUM (
   CASE
    WHEN (ps.index_id < 2) THEN row_count
    ELSE 0
   END
   ) AS [rows],
  SUM (ps.reserved_page_count) AS reserved,
  SUM (
   CASE
    WHEN (ps.index_id < 2) THEN
     (ps.in_row_data_page_count + ps.lob_used_page_count + ps.row_overflow_used_page_count)
    ELSE (ps.lob_used_page_count + ps.row_overflow_used_page_count)
   END
   ) AS data,
  SUM (ps.used_page_count) AS used
FROM sys.dm_db_partition_stats ps
GROUP BY ps.object_id) AS a1
LEFT OUTER JOIN
(SELECT
  it.parent_id,
  SUM(ps.reserved_page_count) AS reserved,
  SUM(ps.used_page_count) AS used
  FROM sys.dm_db_partition_stats ps
  INNER JOIN sys.internal_tables it ON (it.object_id = ps.object_id)
  WHERE it.internal_type IN (202,204)
  GROUP BY it.parent_id) AS a4 ON (a4.parent_id = a1.object_id)
INNER JOIN sys.all_objects a2  ON ( a1.object_id = a2.object_id )
INNER JOIN sys.schemas a3 ON (a2.schema_id = a3.schema_id)
WHERE a2.type <> \'S\' and a2.type <> \'IT\'
group by a3.name
ORDER BY a3.name
end try
begin catch
select
-100 as l1
, 1 as schemaname
,       ERROR_NUMBER() as tablename
,       ERROR_SEVERITY() as row_count
,       ERROR_STATE() as reserved
,       ERROR_MESSAGE() as data
,       1 as index_size
,   1 as unused
end catch

运行返回模式空间使用情况的结果(见图六)

总结

　　通过执行上述查询，我们就能够根据表或根据模式来查明空间使用情况，并将返回的结果在一个表中显示。