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RDS SQL Server死鎖（Deadlock）係列之四利用Service Broker事件通知捕獲死鎖
問題引入
在前麵三篇文章，我們分別談到了使用DBCC命令捕獲死鎖；使用Profiler界麵跟蹤Deadlock Graph事件捕獲死鎖和使用腳本自動部署Profiler Trace捕獲死鎖。這篇文章介紹一個非常有意思的捕獲死鎖的方法：使用SQL Server Service Broker Event Notification來捕獲死鎖。
Service Broker Event Notification
Service Broker Event Notification即使用SQL Server引擎內置的異步消息通訊機製加上SQL Server的事件通知機製來捕獲死鎖信息，這個方法非常簡單，對SQL Server數據庫本身影響非常小。一個簡單的模型是將捕獲到的死鎖xml信息存放在隊裏中，然後分析隊列，重現詳細的死鎖場景。代碼如下：
USE [master]
GO
IF DB_ID('DeadlockCapture') IS NULL
CREATE DATABASE [DeadlockCapture];
GO
ALTER DATABASE [DeadlockCapture]
SET ENABLE_BROKER
GO
USE [DeadlockCapture]
GO
--Create Event Notification Queue to save Deadlock Info
CREATE QUEUE QueueDeadLockNotification
;
--Create Event Notification Services
CREATE SERVICE ServiceDeadlockNotification
ON QUEUE QueueDeadLockNotification ([https://schemas.microsoft.com/SQL/Notifications/PostEventNotification]);
GO
-- Create route for the DeadlockNotificationSvc
CREATE ROUTE RouteDeadLockNotification
WITH SERVICE_NAME = 'ServiceDeadlockNotification',
ADDRESS = 'LOCAL';
GO
-- Create Event Notification for the deadlock_graph event.
CREATE EVENT NOTIFICATION DeadLockNotificationEvent
ON SERVER
FOR DEADLOCK_GRAPH
TO SERVICE
'ServiceDeadlockNotification',
'current database'
GO
死鎖測試的方法和過程參見文章RDS SQL Server死鎖（Deadlock）係列之一使用DBCC捕獲死鎖中死鎖測試部分，在此不再累述。
分析死鎖
當死鎖發生後，死鎖信息會被異步的記錄到Service Broker隊列中。
USE [DeadlockCapture]
GO
select CAST(message_body as xml),* from QueueDeadLockNotification
查詢結果展示如下：
接下來的工作就是分析隊裏中的死鎖信息，分析方法和前麵幾篇文章的分析方法大同小異，隻是在公用表達式的初始化部分稍有差異。方法如下：
use master
go
;WITH DATA
AS
(
-- Analysis deadlock when saving into Service Broker Event Notification
select
RowNumber = row_number() OVER (ORDER BY queuing_order)
,DeadlockGraph = CAST(message_body as xml).query('./EVENT_INSTANCE/TextData/deadlock-list')
from [DeadlockCapture].[dbo].[QueueDeadLockNotification] WITH(NOLOCK)
)
,
deadlock
AS
(
SELECT
RowNumber
,OwnerID = T.C.value('@id', 'varchar(50)')
,SPid = T.C.value('(./@spid)[1]','int')
,status = T.C.value('(./@status)[1]','varchar(10)')
,Victim = case when T.C.value('@id', 'varchar(50)') = T.C.value('./../../@victim','varchar(50)') then 1 else 0 end
,LockMode = T.C.value('@lockMode', 'varchar(20)')
,DeadlockGraph
,Inputbuf = T.C.value('(./inputbuf/text())[1]','varchar(max)')
,Code = T.C.value('(./executionStack/frame/text())[1]','VARCHAR(max)')
,SPName = T.C.value('(./executionStack/frame/@procname)[1]','sysname')
,Hostname = T.C.value('(./@hostname)[1]','sysname')
,Clientapp = T.C.value('(./@clientapp)[1]','varchar(max)')
,LoginName = T.C.value('@loginname', 'varchar(20)')
,Action = T.C.value('(./@transactionname)[1]','varchar(max)')
,TransactionTime = T.C.value('@lasttranstarted', 'datetime')
FROM DATA AS A
CROSS APPLY DeadlockGraph.nodes('deadlock-list/deadlock/process-list/process') AS T(C)
)
,
keylock
AS
(
SELECT
OwnerID = T.C.value('./owner[1]/@id', 'varchar(50)')
,KeylockObject = T.C.value('./../@objectname', 'varchar(200)')
,Indexname = T.C.value('./../@indexname', 'varchar(200)')
,IndexLockMode = T.C.value('./../@mode', 'varchar(20)')
FROM DATA AS A
CROSS APPLY DeadlockGraph.nodes('deadlock-list/deadlock/resource-list/keylock/owner-list') AS T(C)
)
SELECT
A.SPid
,is_Vitim = A.Victim
,A.SPName
,A.Code
,A.LockMode
,B.Indexname
,B.KeylockObject
,B.IndexLockMode
,A.Inputbuf
,A.Hostname
,A.LoginName
,A.Clientapp
,A.Action
,status
,A.TransactionTime
FROM deadlock AS A
LEFT JOIN keylock AS B
ON A.OwnerID = B.OwnerID
ORDER BY A.RowNumber,A.Victim
展示結果如下圖所示：
最後總結
使用Service Broker Event Notification來捕獲死鎖信息，是一個比較新穎的選擇，由於采用異步消息通訊的方式，對SQL Server影響非常小。個人建議使用該方法來捕獲、分析死鎖。
最後更新：2017-04-25 10:00:36