RESOURCE_SEMAPHORE wait stats mean a query is waiting for memory before it can even start. On Night 25 at the Clipboard Diner, a wedding party reserves the whole counter and two birthday parties wait. Then I show how to find waiting grants, why grants grow too big, and the fixes I try first.
Optimized Locking Wait Stats: New Lock Waits in SQL Server 2025
Optimized locking wait stats are the new lock waits SQL Server 2025 records when optimized locking is on. On Night 24 at the Clipboard Diner, a new state code swaps booth cards for wristbands. Then I show what LCK_M_S_XACT_MODIFY and LCK_M_S_XACT_READ mean, how to check the setting, and why a long transaction still hurts.
OLEDB Wait Stats: Linked Servers and Remote Calls
OLEDB wait stats measure the time SQL Server spends in calls to an OLE DB provider, and that usually means a linked server. On Night 23 at the Clipboard Diner, the pie case is empty and Jules crosses the street for every slice. Learn how to find the waiting session, how OPENQUERY filters on the remote side, and when to keep a local copy instead.
HADR_SYNC_COMMIT Wait Stats: Availability Group Commits
HADR_SYNC_COMMIT wait stats measure how long a commit waits for a synchronous secondary replica to harden the log. On Night 22 at the Clipboard Diner, every sale is phoned to a sister diner before the plate can leave. Learn what the wait includes, how to read the send and redo queues, and the fixes from the secondary’s log disk to asynchronous commit.
ASYNC_NETWORK_IO Wait Stats: When the Application Is Slow
ASYNC_NETWORK_IO wait stats mean SQL Server has results ready and is waiting for the application to read them. On Night 21 at the Clipboard Diner, hot plates pile up at the pass while Quinn tells a long story at table 4. Learn the causes in the order I find them, two queries that name the slow program, and why the fixes live in the application.
MSQL_XP Wait Stats: Extended Procedures and External Code
MSQL_XP wait stats measure the time a query waits while an extended stored procedure such as xp_cmdshell or xp_dirtree runs. On Night 20 at the Clipboard Diner, an outside caterer takes over one station behind a curtain. Then two queries show you which session is waiting and which procedure it called, and the fixes move that work outside SQL Server.
PREEMPTIVE Wait Stats: Calls Outside SQL Server
PREEMPTIVE wait stats record the time a task spends in code outside SQL Server, such as a call into Windows. On Night 19 at the Clipboard Diner, Kit picks up the wall phone to town hall and steps off the kitchen’s schedule. Then two queries find the preemptive waits that matter on your server.