Does NOLOCK really applies no lock? No. NOLOCK takes a Sch-S, or schema stability, lock. Here is a simple script to see it for yourself.
Diagnosing Blocking Chains With sys.dm_exec_requests
Trace blocking chains from active requests to a candidate head session, inspect sleeping transactions, and verify the owner before action.
SQL SERVER – Always On Availability Groups and Full-Text Index
Read queries were blocked on a secondary replica. Here is a common issue you may face when you use full-text index with Always On Availability Groups.
Decoding wait_resource: From a KEY or PAGE Lock to the Table
Decode wait_resource for blocked requests, map KEY and PAGE locks to objects, and keep undocumented row-hash checks on test copies.
SQL SERVER – 3 Different Usage of DBCC SQLPERF
DBCC SQLPERF can report log usage or reset cumulative wait and latch statistics. I separate reporting from resetting the baseline.
Upsert Patterns in SQL Server Without Race Conditions
Compare upsert patterns under concurrent calls, protect missing-key ranges, test MERGE with HOLDLOCK, and keep unique keys as a guard.
A Retry Loop in T-SQL for Deadlock Victims and Lock Timeouts
Build a bounded retry loop for deadlock and lock-timeout errors, roll back each failed transaction, and keep diagnostics beside retries.