tempdb is one scratch database shared by every database on the instance. The three kinds of thing that land in it, why it is rebuilt at every restart, and the reason its file count keeps coming up.
The Last Actual Execution Plan: LAST_QUERY_PLAN_STATS in Practice
Capture the last actual execution plan with LAST_QUERY_PLAN_STATS, inspect runtime rows, and understand what cache retention cannot provide.
Scale Up or Scale Out: Signs Your Server Needs More Hardware
Decide when to scale up SQL Server by checking sustained CPU demand, memory pressure, storage latency, and whether query tuning comes first.
SQL Server on a Virtual Machine: What Actually Changes
SQL Server on a virtual machine cannot see the host it is sharing. Why more virtual processors can be slower, what memory reservation buys you, why snapshots are not backups, and the four things I check first.
What Is a Deadlock in SQL Server?
A deadlock in SQL Server is two sessions each holding what the other needs. I caused one on purpose and read error 1205. Why it is not the same as blocking, who gets killed, and the boring fix that works.
Overlapping Indexes With INCLUDE Columns: Merging Them Safely
Find overlapping indexes, compare ordered keys and INCLUDE lists, merge coverage carefully, and review usage before removing either index.
Why Queries Recompile
Why queries recompile becomes clearer when you capture Extended Events causes and check schema changes, statistics, SET options, and temp tables.