How can i delete 3rd row of my table which is having only 1 column and all 5 records have same value?

Ex. Table-T1

Id
——-
2
2
2
2
2

Thanks

Avani

To force deletion of ghost records run:

DBCC FORCEGHOSTCLEANUP

Perhaps you can explain / clarify a somewhat similar scenario regarding variable length columns.

When changing / deleting a column with a LOB data type (text, ntext, xml, etc), the space used is not deallocated. It is not even deallocated over time. A DBCC CLEANTABLE(‘DBName’, ‘TableName’) will update the information displayed in sys.dm_db_index_physical_stats and now recognize that clustered index as having unused space, however this seems like a major flaw within SQL Server. I regard the developers and engineers whom build such an amazing technology as ‘brilliant’, so I must believe there is a good reason for this behavior.

I may also be missing some important details on this, so any clarification on this would be appreciated!

Thanks so much for all your hard work and great information you provide the community.

Ryan

Can u please help me,how to deallocate the space used by the tavles which had been deleted.

You are absolutely correct and based on your feedback, I have modified this blog post.

Many thanks again for taking time and providing accurate feedback.

Kind Regards,
Pinal

I have ran this example on SQL Server 2008 R2 and got the results.

I will now run this again with some extensive wait time and will post the results.

Thank you again for writing on this blog.

If this is wrong I will correct it with proper credit to you.

Kind Regards,
Pinal

Heaps:
BOL: “When rows are deleted from a heap the Database Engine may use row or page locking for the operation. As a result, the pages made empty by the delete operation remain allocated to the heap. When empty pages are not deallocated, the associated space cannot be reused by other objects in the database.”
While it may appear that the pages are not deallocated due to you example set size, try increasing the number of inserted rows and you will see that the table size gets reduced to around 25MB. The number of index pages reduces accordingly. (Levels do not apply to heaps)
If on the other hand you put a TABLOCK hint in the delete statement all pages will get deallocated.

Tables with a Clustered Index:
Deleting from a table with a clustered index will deallocate deleted pages regardless of the TABLOCK hint. The difference is that without the hint it will happen by a background clean up process and therefore might not be visible immediately after the delete. Try waiting for a few seconds and check space used. TABLOCK will make this operation synchronous.
Number index levels are kept the same, BUT the size of ALL levels gets reduced and not just the leaf levels.

Reducing the size of the heap or the levels of indexes in the B-Tree can be achieved in several ways: if the table is empty (and other constraints satisfied) TRUNCATE TABLE will do the work. Other methods are rebuilding the table/clustered index.

Regards,

Hrvoje Piasevoli
@HrvojePiasevoli