AI generated ETL ran clean on the first try, and it took six weeks to find out what it was missing. A late Monday file, a file sent twice, a file full of zeros and mangled names all got through. The ugly old job had a rule for every one of them, and nobody had written those rules down. Now I ask AI for the failure list before I ask for any code.
Ordered Clustered Columnstore Index for Better Rowgroup Elimination
Build an ordered clustered columnstore on SaleDate, compare segment ranges and skipped segments, and review how later loads affect order.
rows_sampled: Checking How Much Data Your Statistics Saw
A fresh statistic can still come from a small sample. Compare rows with rows_sampled and see how a sample misjudges a rare value.
Masking Test Data With REGEXP_REPLACE in SQL Server 2025
Before a production copy reaches a developer, replace the real emails and phone numbers. Here is a small, checked way to do it with REGEXP_REPLACE.
Recent Rows Only: A Filtered Index for the Data Everyone Reads
A filtered index for recent rows is small and fast, but its date never moves by itself. Here is how to build it, test it and keep it fresh.
Columnstore Bulk Load: Why Batch Size Decides Where Rows Land
Review columnstore bulk load batch sizes, inspect delta and compressed rowgroups, and measure the cost of forcing small groups to compress.
The money Data Type: Where Division and Rounding Go Wrong
Dividing money by money loses digits before any cast can save them. Here is the one-third demo, and how to find the leftover penny.