数据库的硬盘空间使用

Posted 2020-09-12

SQL Server占用的存储空间，包含数据库file占用的存储空间，数据库对象占用的存储空间。

一，数据库file占用的存储空间

1，使用 sys.master_files 查看数据库中各个file占用的存储空间

select db.name as database_name,
    db.is_auto_shrink_on,
    db.recovery_model_desc,
    mf.file_id,
    mf.type_desc,
    mf.name as logic_file_name,
    mf.size*8/1024/1024 as size_gb,
    mf.physical_name,    --mf.max_size,    mf.growth,
    mf.is_percent_growth,
    mf.state_descfrom sys.databases db 
inner join sys.master_files mf 
    on db.database_id=mf.database_idwhere mf.size*8/1024/1024>1  -- GBorder by size_gb desc

2，使用sp_spaceused 查看当前DB的空间使用量

use DB_Studygoexec sys.sp_spaceused

database_size：database_size includes both data and log files.

数据文件的空间利用信息：

• unallocated space ：Space in the database that has not been reserved for database objects.

• reserved：Total amount of space allocated by objects in the database.

• data：Total amount of space used by data.

• index_size：Total amount of space used by indexes.

• unused ：Total amount of space reserved for objects in the database, but not yet used.

• database_size will always be larger than the sum of reserved + unallocated space because it includes the size of log files, but reserved and unallocated_space consider only data pages.

3， 按照extent统计data file的disk space usage

从系统page：GAM 和 SGAM 上读取Extent allocate 信息，计算data file有多少extent allocated 或 unallocated。

计算公式：1Extent=8Pages，1Page=8KB

dbcc showfilestats

4， 统计SQL Server 实例中所有数据库的日志文件的disk space usage

dbcc sqlperf(logspace) 返回的结果总是准确的，语句的执行不会对sql server增加负担

dbcc sqlperf(logspace)

二，查看数据库中，各个table 或index 所占用的disk space

1，查看数据库所有table 或index 所占用的disk space

select 
    t.name,    sum(case when ps.index_id<2 then ps.row_count else 0 end) as row_count,    sum(ps.reserved_page_count)*8/1024/1024 as reserved_gb,    sum(ps.used_page_count)*8/1024 as used_mb,    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 0 end
        )*8/1024 as data_used_mb,    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 0 end
        )*8/1024 as index_used_mbfrom sys.dm_db_partition_stats psinner join sys.tables t    on ps.object_id=t.object_idgroup by t.object_id, t.nameorder by reserved_gb desc

2，在当前DB中，查看某一个Table object 空间使用信息

exec sp_spaceused ‘dbo.dt_study‘

rows:Number of rows existing in the table.

reserved:Total amount of reserved space for objname.

data:Total amount of space used by data in objname.

index_size:Total amount of space used by indexes in objname.

unused:Total amount of space reserved for objname but not yet used.

三，使用Standard Reports 查看disk space usage

 

四，查看服务器各个逻辑盘符剩余的disk space

Exec master.sys.xp_fixeddrives

 

Appendix：

查看数据库中table，indexed等对象的disk空间使用量，但是返回的结果并不十分精确。

sp_spaceused Displays the number of rows, disk space reserved, and disk space used by a table, indexed view, or Service Broker queue in the current database, or displays the disk space reserved and used by the whole database.

Syntax

sp_spaceused [[ @objname = ] ‘objname‘ ] 
        [,[ @updateusage = ] ‘updateusage‘ ]

Arguments          

• [ @objname=] ‘objname‘              

• Is the qualified or nonqualified name of the table, indexed view, or queue for which space usage information is requested.Quotation marks are required only if a qualified object name is specified. If a fully qualified object name (including a database name) is provided, the database name must be the name of the current database.  If objname is not specified, results are returned for the whole database.  default objname is NULL. 

• [ @updateusage=] ‘updateusage‘              

• Indicates DBCC UPDATEUSAGE should be run to update space usage information. When objname is not specified, the statement is run on the whole database; otherwise, the statement is run on objname. Values can be true or false.updateusage is varchar(5), with a default of false.

Remarks

When updateusage is specified, the SQL Server Database Engine scans the data pages in the database and makes any required corrections to the sys.allocation_units and sys.partitions catalog views regarding the storage space used by each table. There are some situations, for example, after an index is dropped, when the space information for the table may not be current. updateusage can take some time to run on large tables or databases. Use updateusage only when you suspect incorrect values are being returned and when the process will not have an adverse effect on other users or processes in the database. If preferred, DBCC UPDATEUSAGE can be run separately.

Note:When you drop or rebuild large indexes, or drop or truncate large tables, the Database Engine defers the actual page deallocations, and their associated locks, until after the transaction commits. Deferred drop operations do not release allocated space immediately. Therefore, the values returned by sp_spaceused immediately after dropping or truncating a large object may not reflect the actual disk space available.