Glenn Berryの診断クエリとAdam MachanicのSP_Whoisactiveを使用して、実際に何が起こっているのかを確認します。
最初に、このクエリを実行して、どのデータベースファイルのIOボトルネックが最も大きいかを確認します（クエリby Glenn Berry）
SELECT DB_NAME(fs.database_id) AS [Database Name] ,
mf.physical_name ,
io_stall_read_ms ,
num_of_reads ,
CAST(io_stall_read_ms / ( 1.0 + num_of_reads ) AS NUMERIC(10, 1)) AS [avg_read_stall_ms] ,
io_stall_write_ms ,
num_of_writes ,
CAST(io_stall_write_ms / ( 1.0 + num_of_writes ) AS NUMERIC(10, 1)) AS [avg_write_stall_ms] ,
io_stall_read_ms + io_stall_write_ms AS [io_stalls] ,
num_of_reads + num_of_writes AS [total_io] ,
CAST(( io_stall_read_ms + io_stall_write_ms ) / ( 1.0 + num_of_reads
+ num_of_writes ) AS NUMERIC(10,
1)) AS [avg_io_stall_ms]
FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS fs
INNER JOIN sys.master_files AS mf WITH ( NOLOCK ) ON fs.database_id = mf.database_id
AND fs.[file_id] = mf.[file_id]
ORDER BY avg_io_stall_ms DESC
OPTION ( RECOMPILE );
次に、このクエリを実行して、サーバーが待機している上位10のイベントを確認します（Jonathan Kehayiasによるクエリ）。Glenn Berryの診断クエリからも同様のクエリが見つかります。
SELECT TOP 10
wait_type ,
max_wait_time_ms wait_time_ms ,
signal_wait_time_ms ,
wait_time_ms - signal_wait_time_ms AS resource_wait_time_ms ,
100.0 * wait_time_ms / SUM(wait_time_ms) OVER ( ) AS percent_total_waits ,
100.0 * signal_wait_time_ms / SUM(signal_wait_time_ms) OVER ( ) AS percent_total_signal_waits ,
100.0 * ( wait_time_ms - signal_wait_time_ms )
/ SUM(wait_time_ms) OVER ( ) AS percent_total_resource_waits
FROM sys.dm_os_wait_stats
WHERE wait_time_ms > 0 -- remove zero wait_time
AND wait_type NOT IN -- filter out additional irrelevant waits
( 'SLEEP_TASK', 'BROKER_TASK_STOP', 'BROKER_TO_FLUSH', 'SQLTRACE_BUFFER_FLUSH',
'CLR_AUTO_EVENT', 'CLR_MANUAL_EVENT', 'LAZYWRITER_SLEEP', 'SLEEP_SYSTEMTASK',
'SLEEP_BPOOL_FLUSH', 'BROKER_EVENTHANDLER', 'XE_DISPATCHER_WAIT',
'FT_IFTSHC_MUTEX', 'CHECKPOINT_QUEUE', 'FT_IFTS_SCHEDULER_IDLE_WAIT',
'BROKER_TRANSMITTER', 'FT_IFTSHC_MUTEX', 'KSOURCE_WAKEUP',
'LAZYWRITER_SLEEP', 'LOGMGR_QUEUE', 'ONDEMAND_TASK_QUEUE',
'REQUEST_FOR_DEADLOCK_SEARCH', 'XE_TIMER_EVENT', 'BAD_PAGE_PROCESS',
'DBMIRROR_EVENTS_QUEUE', 'BROKER_RECEIVE_WAITFOR',
'PREEMPTIVE_OS_GETPROCADDRESS', 'PREEMPTIVE_OS_AUTHENTICATIONOPS', 'WAITFOR',
'DISPATCHER_QUEUE_SEMAPHORE', 'XE_DISPATCHER_JOIN', 'RESOURCE_QUEUE' )
ORDER BY wait_time_ms DESC
この情報が手元にあれば、問題のトラブルシューティングがはるかに簡単になります。
ところで、トラブルシューティングにsp_whoisactiveを使用する方法に関する多くの投稿をここで見つけることができます。