Ghost Records are logically deleted index records waiting for physical cleanup. I investigate their context before recommending an intervention.
Querying a Histogram With sys.dm_db_stats_histogram Instead of DBCC
Query sys.dm_db_stats_histogram to inspect statistics steps, compare stored estimates with data, and identify values beyond the last step.
SQL SERVER – Select Unique Data From a Column Exist in Two Different Table
A reader wanted to Select Unique Data from a column in two tables, keeping only values found in just one of them. Here is the query that does it.
SQL SERVER – Simple Explanation of AT TIME ZONE Feature
The AT TIME ZONE feature arrived in SQL Server 2016. Here is a simple two-step example that converts US East Coast time to West Coast time.
How to Kill User Sessions (SPID) in SQL Server? – Interview Question of the Week #141
How do you Kill User Sessions (SPID) in SQL Server? First ask why you want to, since killing busy sessions rarely helps. Then here is the script.
SQL SERVER – The Operating System Returned the Error 21(The Device is Not Ready.) While Attempting ‘GetDiskFreeSpace’ on ‘A:\’
While testing SQL Server 2017, I found Error 21 (the device is not ready) in the ERRORLOG for GetDiskFreeSpace on drive A. Here is why it shows up.
SQL SERVER – New DMV in SQL Server 2017 – sys.dm_os_enumerate_fixed_drives. A Replacement of xp_fixeddrives
SQL Server 2017 adds sys.dm_os_enumerate_fixed_drives, a new DMV that shows free space on each drive and replaces xp_fixeddrives. Here is the query I use.