Top 10 SQL Server Wait Types for Performance Tuning

Understanding these wait types is key to identifying performance bottlenecks in SQL Server:

CXPACKET: Indicates parallelism-related waits. High values suggest inefficiencies in query parallelization.
LCK_M_XX: Lock waits (e.g., LCK_M_S, LCK_M_U) signal queries waiting for resource locks, pointing to potential blocking or deadlocking.
PAGEIOLATCH_XX: Wait times due to disk I/O operations, indicating possible disk subsystem bottlenecks.
SQLCLR: Associated with Common Language Runtime operations. High waits might indicate issues with CLR stored procedures or functions.
THREADPOOL: Queries waiting for available worker threads, common in high workload scenarios.
ASYNC_NETWORK_IO: Occurs when SQL Server waits for a client application to process data, often due to slow clients or network issues.
SOS_SCHEDULER_YIELD: CPU thread voluntarily yielding its time slice, often a sign of CPU pressure.
WRITELOG: Related to writing log buffer to the transaction log, potentially indicating transaction log disk issues.
RESOURCE_SEMAPHORE: Associated with memory pressure where queries wait for memory grants.
BACKUPBUFFER: Pertains to backup operations, with high waits indicating possible backup subsystem issues.

Remember, while these wait types can indicate potential problems, it’s important to consider them in the context of your overall system performance. Sometimes, certain waits might be normal for your specific workload or hardware configuration.