When a sql:variable() value is substituted in the query, it is treated as a literal string, wrapped in double-quotes, instead of as an XML node test. 
Literal strings used by...

Adding...
If you are comparing node values to a variable, use sql:variable("@VariableName") in the XPath.
If you are comparing to another column in the query, use sql:column("ColumnName")

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Leave the current DataMart online while you prepare the new one:
- Create a new database on the DataMart
 - ETL-load that database from your DWH while the current database...

Following up, I rebuilt the table with row-level compression and ran the tests again. The results were the same. The in-memory representation of the data is based not on the...

The counter argument is that while data stored on disk and persisted in the data cache uses actual size (if you use Unicode compression when nvarchar(columns) that hold ASCII...

When you deleted the column, the contents already on disk were not deleted. New rows will go in without the column, but the old data stays on disk until you...

Other places to check when seeing elevated ASYNC_NETWORK_IO waits:
- Check the entire network path between the database server and the client(s). A switch connection somewhere on the path may...

I agree with you that option D is the lesser of those four evils.

The correct answer is:
E - Run CHECKDB with ALL_ERRORMSGS, NO_INFOMSGS, and no repair options to determine the...

The target system (the server to which you are shipping logs) must be on a version equal to *or greater than* the source of the transaction log backups. Upgrade the...

Looks like you're discovering the value of cram sites. Hope your box didn't get rooted going there.

You patch AGs the same way you upgrade them.

https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/upgrading-always-on-availability-group-replica-instances?view=sql-server-2016

-Eddie