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deadlock state. A common implementation method is to undo or suspend some processes to recycle some resources, and then allocate these resources to the blocked processes so that they are ready to continue running. Deadlock Detection and removal measures may make the system obtain better resource utilization and throughput, but the implementation is also the most difficult.
According to the
the deadlock. This is a measure to match the detection of deadlocks. When a deadlock has been detected in the system, the process must be freed from the deadlock state. A common practice is to undo or suspend some processes in order to reclaim some resources, and then assign those resources to a process that is already in a blocked state and make it ready to con
, which makes additional resources available, queries often stop asking for lock base tables, instead of locking the nonclustered indexes, which is better if the index can "overwrite (Cover)" queries. Therefore, the index include column does not only reduce bookmark lookups to improve performance, but also reduces deadlocks. Adding resources can also be done through row versioning after SQL Server 2005, but
the deadlock. This is a measure to match the detection of deadlocks. When a deadlock has been detected in the system, the process must be freed from the deadlock state. A common practice is to undo or suspend some processes in order to reclaim some resources, and then assign those resources to a process that is already in a blocked state and make it ready to con
Find out the source of deadlock and blocking for SQL Server--Find out the source of SQL Server deadlock and blocking
Copy Code code as follows:
Use master
Go
declare @spid int, @bl int
DECLARE S_cur CURSOR f
statement sent to SQL ServerDECLARE CRSR Cursor forSELECT Blk from #Who WHERE [email protected] and blkDECLARE @blk int;Open CRSR;FETCH NEXT from CRSR to @blk;while (@ @FETCH_STATUS = 0)BEGIN;DBCC INPUTBUFFER (@blk);FETCH NEXT from CRSR to @blk;END;Close CRSR;Deallocate CRSR;--Locked resourcesSELECT #Who. Spid,hostname,objid,[type],mode,object_name (ObjID) as objname from #LockJOIN #WhoOn #Who. spid= #Lock. spidand [email protected]WHERE objidDROP Ta
Cursor forSELECT Blk from #Who WHERE [email protected] and blkDECLARE @blk int;Open CRSR;FETCH NEXT from CRSR to @blk;while (@ @FETCH_STATUS = 0)BEGIN;DBCC INPUTBUFFER (@blk);FETCH NEXT from CRSR to @blk;END;Close CRSR;Deallocate CRSR;--Locked resourcesSELECT #Who. Spid,hostname,objid,[type],mode,object_name (ObjID) as objname from #LockJOIN #WhoOn #Who. spid= #Lock. spidand [email protected]WHERE objidDROP Table #Who;DROP Table #Lock;(2). Use SQL
Cursor forSELECT Blk from #Who WHERE [email protected] and blkDECLARE @blk int;Open CRSR;FETCH NEXT from CRSR to @blk;while (@ @FETCH_STATUS = 0)BEGIN;DBCC INPUTBUFFER (@blk);FETCH NEXT from CRSR to @blk;END;Close CRSR;Deallocate CRSR;--Locked resourcesSELECT #Who. Spid,hostname,objid,[type],mode,object_name (ObjID) as objname from #LockJOIN #WhoOn #Who. spid= #Lock. spidand [email protected]WHERE objidDROP Table #Who;DROP Table #Lock;(2). Use SQL
The SQL Server database deadlock is generally caused by two or more trans requesting a specific actual application object being requested by the other party, resulting in mutual waiting. A simple example is as follows:
The SQL Server database
cursor local for select distinct hostname from # TBOpen TBFetch next from TB into @ hostnameWhile @ fetch_status = 0BeginSet @ SQL = 'ping' + @ hostname + '-a-n 1-l 1'Insert # IP (a) exec master .. xp_mongoshell @ SQLUpdate # IP Set hostname = @ hostname where hostname is nullFetch next from TB into @ hostnameEndUpdate # TB set net_ip = left (A, patindex ('%: %', a)-1)From # TB a inner join (Select hostname, A = substring (A, patindex ('Ping statisti
is just know, do not know the experience once know, know that there is no pride or inferiorityYour knowledge corner can not deny your technical ability, application level of things, but it is in the people make good rules to play games, no one to pretend.Reference:Https://www.cnblogs.com/Uest/p/4998527.htmlhttps://blogs.msdn.microsoft.com/apgcdsd/2012/02/27/sql-serverdeadlock/https://www.simple-talk.com/sql
SQL server deadlock 1:A user A accesses table A (locking table A) and then accesses Table BAnother user B accesses Table B (Table B is locked) and then attempts to access TableAt this time, user A has locked Table B because user B has to wait for User B to release Table B to continue. Well, the old man will have to wait honestly.Similarly, User B has to wait for
When it comes to SQL Server, the most frustrating thing is the locking mechanism. In the default Read Committed isolation mode, even the most basic select operation has to apply for a variety of granularity locks, and in the process of reading data will continue to lock upgrade, conversion. In a non-uncommitted read isolation level, a select operation adds an S lock on each read record or key value (when th
deadlocks are listed at the beginning, so you can avoid deadlocks if you try to destroy any 1 or more of these conditions. The following methods help minimize deadlocks:A) Access the object in the same order;b) Avoid user interaction in the transaction, that is, do not include user interaction during the execution of the transaction; c) keep the transaction short and in a batch; d) SELECT statement Plus wi
(' kill '[email protected])FETCH NEXT from #tb into @spidEndClose #tbDeallocate #tb GOSET QUOTED_IDENTIFIER OFFGOSET ANSI_NULLS onGO SET QUOTED_IDENTIFIER ONGOSET ANSI_NULLS onGO ALTER proc P_killspid@dbname varchar (200)--the database name of the process to be closedAsdeclare @sql nvarchar (500)declare @spid nvarchar (20) DECLARE #tb cursor FORSelect Spid=cast (spid as varchar) from master: sysprocesses where dbid=db_id (@dbname)Open #tbFETCH NEXT
SQL Server checks whether tasks are not submitted, stops the progress, and removes the table deadlock. the SQL Server process is deadlocked.
If there are uncommitted tasks in the data warehouse, the related tables will remain in the dead warehouse, affects the query of oth
.
In fact, in sqlserver 2005, if you use profiler to capture eventid: 1222, a deadlock chart will appear, which is very intuitive.
The following method helps minimize the number of deadlocks (For details, refer to sqlserver online help and search: to minimize the number of deadlocks on SQL Server.
Access objects in the same order.
methods help minimize deadlocks (for details, see SQL Server online Help, search: Minimize deadlocks.)· Access the object in the same order.· Avoid user interaction in a transaction.· Keep the transaction short and in a batch.· Use a lower isolation level.· Use the isolation level based on row versioning.-Set the READ_COMMITTED_SNAPSHOT database option to on so
A deadlock occurs if two user processes lock different resources and then attempt to lock resources that are locked by the other. At this point, SQL Server automatically selects and aborts one of the processes to unlock the deadlock, allowing another process to continue processing. The system will rollback the aborted
This article is reproduced articles, the description is very good, has not been verified.I've recently encountered a deadlock problem that seems strange and interesting to analyze. This deadlock seems to be hard to understand. In the analysis process, a lot of typical methods of parsing SQL Server
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