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What happens when you disable ghost cleanup in SQL Server?
Since the ghost cleanup process removes records that are marked as ghosts, disabling the process will leave these records on the page, preventing SQL Server from reusing this space. This forces SQL Server to add data to new pages instead, leading to bloated database files, and can also cause page splits.
Why is ghost cleanup not freeing up space?
The only different thing was that the original database was synched under an Availability Group. I disconnected the database from the Availability Group and now I can see that the GHOST_CLEANUP task is slowly freeing space. I will assume that the problem was the Availability Group, but does anyone know WHY !?
How often does the ghost cleanup process run?
This background process runs sometime after the delete transaction is committed, and physically removes ghosted records from pages. The ghost cleanup process runs automatically on an interval (every 5 seconds for SQL Server 2012+, every 10 seconds for SQL Server 2008/2008R2) and checks to see if any pages have been marked with ghost records.
Why are there so many Ghost Records in SQL Server?
The cause was identified as a growing number of ghost records that SQL Server would not clean up no matter what. Our fix was ultimately to restart SQL Server. Here’s what we found. At time marked ‘A’ on the graph, we noticed that CPU increased dramatically.
What does it mean when a record is ghosted in SQL Server?
Records that are deleted from a leaf level of an index page aren’t physically removed from the page – instead, the record is marked as ‘to be deleted’, or ghosted. This means that the row stays on the page but a bit is changed in the row header to indicate that the row is really a ghost.
What to do when Ghost cleanup is disabled?
Once the ghost cleanup process is disabled, some action needs to be taken to remove the ghosted records. One option is to execute an index rebuild, which will move data around on pages.