Hypothetical indexes are leftovers from the Database Engine Tuning Advisor. They hold a name and statistics but no data. This post lists them, shows they cannot serve a query, and drops them in two steps: a list you read first, and a drop second.
Eager Index Spool: When the Plan Builds Its Own Index
Investigate an eager index spool, read seek keys and output, and compare a supporting index with the cost of rebuilding temporary storage.
Index Key Columns and Included Columns in SQL Server
Index key columns and included columns show what each index really stores. This post builds one query that lists them for every index, then a second query that finds indexes with the same keys or a shared leading key. It ends with the rules for merging them safely.
Update Statistics With FULLSCAN and MAXDOP in SQL Server
To update statistics with FULLSCAN in parallel, add MAXDOP to the statement. This post builds a table of 3 million rows, times the update with MAXDOP 1, the instance default and 8, and shows which statistics speed up and which do not.
SQL SERVER – Say No To Database Engine Tuning Advisor
I review Database Engine Tuning Advisor recommendations against the workload before applying them. That was the point behind my original opinion.
WRITELOG Waits: Finding What Slows Transaction Log Writes
Diagnose WRITELOG waits with log-file latency, commit patterns, and measured choices for batching, storage, and durability.
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.