Database Topic Archive
Wait statistics, tempdb, Query Store, Always On availability groups, and SQL Server operations notes.
Same procedure, two seconds for one tenant, thirty-second timeouts for another. How to prove parameter sniffing with plan variance, and the fix toolkit ranked from better indexes to 2022's Parameter Sensitive Plan optimization.
One database setting ended our reader-writer blocking overnight and introduced two bugs we only caught in a concurrency soak. RCSI mechanics, the honest migration checklist, and the version-store monitoring that keeps tempdb safe.
A week of error 1205s and a proposed retry loop that would fix nothing. How to pull deadlock graphs from system_health, read victim, owner, and waiter nodes, and kill the three patterns behind most deadlocks.
The deploy that doubled p95 left its fingerprints in sys.query_store_runtime_stats. How to configure Query Store so the data is there when you need it, compare intervals to find the regressed plan, and force a plan without fooling yourself.
The nightly REBUILD job I inherited burned 90 GB of transaction log and fixed nothing. What fragmentation still means on flash, what REBUILD actually buys over REORGANIZE, and why updating statistics is usually the real win.
Since-restart wait totals average your quietest night and your worst deploy into one meaningless number. Here is how I diff sys.dm_os_wait_stats over an interval, drop the benign noise list, and branch on what CXPACKET, PAGEIOLATCH, WRITELOG, and LCK_M_* are actually…
A batch job that got slower as we added workers was queueing on three pages in tempdb. How to tell PAGELATCH from PAGEIOLATCH, size the data files, weigh memory-optimized metadata in 2019, and keep the version store from eating the…