Sự kiện chờ SQL Server -1

Xin chào,

Bạn sẽ thấy rằng sự kiện chờ nào nằm trong cơ sở dữ liệu SQL Server.

Để giải quyết sự chậm chạp của cơ sở dữ liệu SQL Server, bạn nên tìm sự kiện chờ nào tồn tại trong cơ sở dữ liệu.

Bạn có thể tìm thấy các sự kiện chờ của cơ sở dữ liệu với truy vấn sau.

with waits as
(select
wait_type,
wait_time_ms / 1000.0 as waits,
(wait_time_ms - signal_wait_time_ms) / 1000.0 as resources,
signal_wait_time_ms / 1000.0 as signals,
waiting_tasks_count as waitcount,
100.0 * wait_time_ms / sum (wait_time_ms) over() as percentage,
row_number() over(order by wait_time_ms desc) as rownum
from sys.dm_os_wait_stats
where wait_type not in (
N'CLR_SEMAPHORE', N'LAZYWRITER_SLEEP',
N'RESOURCE_QUEUE', N'SQLTRACE_BUFFER_FLUSH',
N'SLEEP_TASK', N'SLEEP_SYSTEMTASK',
N'WAITFOR', N'HADR_FILESTREAM_IOMGR_IOCOMPLETION',
N'CHECKPOINT_QUEUE', N'REQUEST_FOR_DEADLOCK_SEARCH',
N'XE_TIMER_EVENT', N'XE_DISPATCHER_JOIN',
N'LOGMGR_QUEUE', N'FT_IFTS_SCHEDULER_IDLE_WAIT',
N'BROKER_TASK_STOP', N'CLR_MANUAL_EVENT',
N'CLR_AUTO_EVENT', N'DISPATCHER_QUEUE_SEMAPHORE',
N'TRACEWRITE', N'XE_DISPATCHER_WAIT',
N'BROKER_TO_FLUSH', N'BROKER_EVENTHANDLER',
N'FT_IFTSHC_MUTEX', N'SQLTRACE_INCREMENTAL_FLUSH_SLEEP',
N'DIRTY_PAGE_POLL', N'SP_SERVER_DIAGNOSTICS_SLEEP')
)
select
w1.wait_type as waittype, 
cast (w1.waits as decimal(14, 2)) wait_s,
cast (w1.resources as decimal(14, 2)) resource_s,
cast (w1.signals as decimal(14, 2)) signal_s,
w1.waitcount wait_count,
cast (w1.percentage as decimal(4, 2)) percentage,
cast ((w1.waits / w1.waitcount) as decimal (14, 4)) avgWait_s,
cast ((w1.resources / w1.waitcount) as decimal (14, 4)) avgResource_s,
cast ((w1.signals / w1.waitcount) as decimal (14, 4)) avgSignal_s
from waits as w1
inner join waits as w2 on w2.rownum <= w1.rownum
group by w1.rownum, w1.wait_type, w1.waits, w1.resources, w1.signals, w1.waitcount, w1.percentage
having sum (w2.percentage) - w1.percentage < 95; -- percentage threshold