SQL-Server: sp_spaceused gives zero rows but big dataSize for cleaned table

Question

After cleaning my table with DELETE FROM MyTable (and executing DBCC shrinkdatabase('MyDB') should that matter) I run the statement EXEC sp_spaceused MyTable. The results confuse me:

tableName   numberOfRows   reservedSize   dataSize   indexSize   unusedSize
---------   ------------   ------------   --------   ---------   ----------
MyTable     0              21664 KB       20672 KB   736 KB      256 KB

As you can see there are zero rows, yet there's almost 21 MB of data. My question is: what are possible causes for this situation and/or how can I further investigate this?

Answer 1

DELETE does not reclaim space, it deletes rows.

Space can remain allocated for several reasons, 3 of which are:

• ghost clean up is still running
• the table has no clustered index
• the system tables are not updated yet

Try

• EXEC sp_spaceused 'MyTable', 'true' to force a space used update
• TRUNCATE TABLE which deallocates space, rather then deleting rows
• DELETE myTABLE WITH (TABLOCKX) 如果没有聚集索引并且不能使用 TRUNCATE

不要运行，DBCC shrinkdatabase因为它没有增加任何价值，它只会再次增长