SQL DBA Blog: Home

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? Modest background amounts, no; our SQL Server 2025 lab had about 400 waits totalling 0.7 seconds in a day. Get Wait Statistics does not filter it out, so if it…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? At small levels, no; it is not a known contention point, and it was zero on our SQL Server 2025 lab. Get Wait Statistics does not filter it out, so…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Many PREEMPTIVE_OS_* waits each track one Windows file call, and this page covers them together: PREEMPTIVE_OS_CLOSEHANDLE, COPYFILE, CREATEDIRECTORY, DELETEFILE, FINDFILE, GETCOMPRESSEDFILESIZE, GETFILEATTRIBUTES, GETFILESIZE, GETFINALFILEPATHBYHANDLE, GETLONGPATHNAME, GETVOLUMENAMEFORVOLUMEMOUNTPOINT, GETVOLUMEPATHNAME, MOVEFILE, OPENDIRECTORY, REMOVEDIRECTORY, SETENDOFFILE, SETFILEPOINTER, WRITEFILE, plus…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? Not in practice; it is not a known contention point. On our SQL Server 2025 lab it had about 6,000 waits and 133 seconds in a day. Get Wait Statistics…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: WRITELOG Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? On Linux, its dominance is expected; on Windows, modest amounts are noise. Our SQL Server 2025 lab, on Windows, had about 1,500 waits totalling 7.6 seconds in a day. Get…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? No at normal levels; it is not a known contention point. Our SQL Server 2025 lab had about 1,500 waits averaging 1 ms in a day. Get Wait Statistics does…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Is It a Problem? The lookup itself is quick; our SQL Server 2025 lab had about 3,900 waits totalling half a second in a day. Get Wait Statistics does not filter it out, so…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting Three preemptive waits track Windows DLL handling, and this page covers them together: PREEMPTIVE_OS_LOADLIBRARY, the Windows LoadLibrary function; PREEMPTIVE_OS_FREELIBRARY, FreeLibrary; and PREEMPTIVE_OS_LIBRARYOPS, the generic wait for other DLL functions. Microsoft lists them as internal…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting ⚡PREEMPTIVE_OS_LOOKUPACCOUNTSID is SQL Server asking Windows to turn a SID into an account name, which for domain accounts can mean a round trip to a domain controller. It becomes a bottleneck when code does…

Read More

⏳Part of the SQL Server Wait Types Library, every wait type explained.Related deep dive: SOS_SCHEDULER_YIELD Wait TypeRelated pillar: Performance & Troubleshooting The remaining single-call preemptive waits do not warrant a page each, so this page covers them together. Microsoft lists them as internal use only, so the names are the guide: each is the Windows…

Read More