"Wait Statistics: What Is It Waiting On?"

1. What does a high `CXPACKET` wait type generally indicate?

High CPU usage Skew in parallelism or bad estimates Sufficient query parallelism Excessive locking issues

2. If you experience a high `PAGEIOLATCH_SH` wait, what is the most likely underlying problem?

Slow network connection Poor index or selective query design High CPU usage Memory pressure

3. What can you infer if you observe high `ASYNC_NETWORK_IO` waits in your SQL Server instance?

Client is not consuming data fast enough There is a disk I/O problem The server is insufficiently powered Blocking from other transactions

4. Which SQL Server command is used to clear wait statistics for a new baseline measurement?

DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR) CHECKPOINT DBCC FREEPROCCACHE SELECT * FROM sys.dm_os_wait_stats