How To Avoid Deadlocks Using Locks On Transactions
Sep 21, 2015
I'm a web developer. our system uses sql server 2012 since it was put in an environment production, what happened one year ago, but only now we are facing a disturbing problem. what happens it's that, when 30 users try to do the same operation in the database, we are getting deadlock status from the db in a few time. we did put this system in production one year ago and now we are facing this kind of problem.
We know that in other dbms using an optimistic lock solves the problem, but it's not our case, 'cause the users are not doing the same operation in a row.
We develop our system in java ee and our db is sql server 2012. These operations might be done on our api.
Hi ChapsCan someone point me in the right direction for a very in depthpractical treatment of this for sql2k.Seen a number of books that skirt around it, read some articles thattouch on it (including some of erlands) but I need more...Thanks for any tips!
I am conducting stress testing for my website and keep getting deadlocks with the following message when one process is adding about 100 records per second and another process is trying to access the data:
Transaction (Process ID 499) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
What do I need to do in my stored procedures to avoid this? I only have ONE stored prcoedure that locks a row while incrementing an ID value. I am not doing any other locks, so is this a SQL Server system lock?
The benifit of UPDLOCK is that it avoids deadlock in case both sessions run the below query at the same time.The table has clustered index on ID column
----session 1 -------- begin transaction select * from a1
update a1 set id = 22 where id = 2
----session 2 -------- begin transaction select * from a1
update a1 set id = 22 where id = 2
Now to avoid deadlock in the above scenario we should use (UPDLOCK) hint in the select statement.Now my question is that deadlock will be avoided in this case when both the sessions use UPDLOCK hint. If only one session uses UPDLOCk and other does not then there will be deadlock .For example session 1 uses UPDLOCK hint this will hold the U lock on the row, but the session 2 does not use this hint and apply shared lock on the same row. Now there will be deadlock when session 1 tries to update the record and is blocked by shared locks of session 2. same will be the case with session 2 and both will wait for each other and hence dead lock.so what steps can be taken to avoid deadlocks in this case. I do not want to use Snapshot isolation.
Hi,I am quite puzzled how SQLServer manages transactions.Whatever the isolation level I set when performing an insertion, otherconnections do not have access to the table in select mode.Example in SQL Analyzer:create table foo (id numeric(10),data varchar(100))On Connection 1SET TRANSACTION ISOLATION LEVEL READ COMMITTEDGOBEGIN TRANSACTIONinsert into foo(id,data) values (1,'data');On Connection 2SET TRANSACTION ISOLATION LEVEL READ COMMITTEDselect * from foo-> QUERY HANGSOn Connection 1COMMITOn Connection 2Get the resultUsing READ COMMITTED level, I was expecting not to lock the table whenperforming the select.Thanks in advance for your help,Cedric
I've got an INSERT that's selecting data from a linked server and attempting to push 10 million rows into the blank table. More or less, it looks like this:
The instance of the SQL Server Database Engine cannot obtain a LOCK resource at this time. Rerun your statement when there are fewer active users. Ask the database administrator to check the lock and memory configuration for this instance, or to check for long-running transactions. There are no other active users. I ran it again and monitored the following DMO to watch the growth of locks for that spid:
SELECT request_session_id, COUNT (*) num_locks -- select * FROM sys.dm_tran_locks --where request_session_id = 77 GROUP BY request_session_id ORDER BY count (*) DESC
The number of locks started small and held for a while around 4-7 locks, but at about 5 minutes in the number of locks held by that spid grew dramatically to more than 8 million before finally erroring again with the same message. Researching, I can't figure out why it's not escalating from row locks to table locks at the appropriate threshold. The threshold in was set to 0 at first (Server Properties > Advanced > Parallelism > Locks). I set it to 5000, and it still didn't seem to work. Rewriting the INSERT to include a WITH (TABLOCK) allows it to finish successfully in testing. My problem is that it's coming out of an ETL with source code that I can't edit. I need to figure out how to force it to escalate to locking the entire table via table or server level settings.
A colleague suggested that installing service packs may take care of it (the client is running SQL Server 2008 R2 (RTM)), but I haven't found anything online to support that theory.
We are migrating our database(s) from ORACLE to SQL. In Oracle we were able to issue a SELECT statement and see all of the locks (Blocking and Non-Blocking) currently in the system. The query also included the Process ID of the process we needed to kill in order to get rid of the lock.
We now need to create the same type of query for Microsoft SQL Server 2012. I have seen postings on different sites saying that this info can be obtained using SP_WHO2 or using the SQL Server Management Studio Activity Monitor's PROCESSES tab, but we are looking for a SELECT statement that will give us similar information.
Hi there, I have decided to move all my transaction handling from asp.net to stored procedures in a SQL Server 2000 database. I know the database is capable of rolling back the transactions just like myTransaction.Rollback() in asp.net. But what about exceptions? In asp.net, I am used to doing the following: <code>Try 'execute commands myTransaction.Commit()Catch ex As Exception Response.Write(ex.Message) myTransaction.Rollback()End Try</code>Will the database inform me of any exceptions (and their messages)? Do I need to put anything explicit in my stored procedure other than rollback transaction? Any help is greatly appreciated
Our system is reasonably complex with a lot of non-trivial stored procedures. As the load on our DB increased we're now getting more and more deadlocks (10 per day or so from about a million stored proc executions).
We try to avoid transactions where we can, and we do attempt to optimse stored procs to steer clear of deadlock conditions, but with the sheer number of stored procedures we can't possibly avoid all deadlock conditions.
One solution I'm considering is to re-run stored procs that failed because of a deadlock. In the .net code we'll run the stored proc, check for a deadlock error and if one happened, wait 100ms and try again.
we have a production inviremont that is running for about 10 months. Since a couple of weeks we are having problems with "Deadlocks".
This cant be due to an increase in data size on the tables that are having the issues because these are cleaned in the same transaction that populates them.
These tables are used to store temporary data that the production system needs to calculate the correct price for any given order. This transaction takes between 0.5 to 1 second to commit.
We are running on a dual processor machine with 1 Gb of RAM with SQL Server 7 - sp 3, Windows NT 4 sp 6, Microsoft Transaction Server.
In all our queries and stored procedures we use the optimizer hints (nolock) for select statements and (rowlock) for updates or deletes.
Is there any way to totally avoid deadlocks. In some critical applications we have removed transactions entirely, counting on other means to maintain database consistency. We still get deadlocks in this area. These are mainly inserts, and the only thing I can think is that updates to the indexes are causing multiple page locks which result in deadlocks. Is this true?
Will deadlocks be eliminated in 7.0 with row level locking for this situation? Or will index page splits still cause a possibility of deadlock contention?
I have a problem with a SP in 6.5. When i try to run a Stored Proc which is a simple select statement dumped into a temp table in a particular database, I lock other users who are tring to log into other databases some in tempdb database. When i try to kill the process the rollback takes almost 45 mins or so..till then no one can log on to the server.
The SP works fine when no one is logged into the Great Plains server. One more thing i observed is that, the SP when run results on a deadlock only when the owner is a user. If the owner is DBO it works fine.
I've got a deadlock problem. The log below has been generated. The problem is that during one day, I have more than 300 deadlocks like it. Before, the were not so many deadlocks. During past year, the number of users has grow (from 100 before to 500 or 700 now)
*** Deadlock Detected *** - Requested by: SPID 360 ECID 0 Mode "S" - Held by: SPID 113 ECID 0 Mode "S" Index: aaaaa_PK Table: TABLE_1 Database: MYDB == Lock: KEY: 22:325576198:1 (ff009ae5078d) - Requested by: SPID 113 ECID 0 Mode "S" - Held by: SPID 374 ECID 0 Mode "X" Index: aaaaa_PK Table: TABLE_1 Database: MYDB == Lock: KEY: 22:325576198:1 (ff009ae5078d) - Requested by: SPID 374 ECID 0 Mode "IX" - Held by: SPID 360 ECID 0 Mode "S" Table: TABLE_2 Database: MYDB == Lock: PAG: 22:1:2428 == Deadlock Lock participant information: Input Buf: S E L E C T the_rest_of_the_query SPID: 360 ECID: 0 Statement Type: UNKNOWN TOKEN Line #: 1 Input Buf: s p _ e x e c u t e 8 Input Buf: s p _ c u r s o r 8À B 8 8f ç @ Table I Input Buf: S E L E C T the_rest_of_the_query SPID: 360 ECID: 0 Statement Type: SELECT Line #: 1 == Session participant information: == Deadlock Detected at: ==> Process 360 chosen as deadlock victim
I have done : - rebuild indexes on all tables (fillfactor 90) - analysed memory activity
Could a lack of memory be at the origin of the problem ? Which counters in perfmon are significant for memory lack ?
Could the index fill factor could be at the origin of the problem ? At time, it is at 90 percent.
Config : Winnt4 Server, MS-SQL 7 SP4 , 2 GB of RAM , 2 x Xeon 700
I have an application built on top of a questionable DB design which requires overcomplicated selects. The application is experiencing deadlocks regularly, in some cases with only one concurrent user.
I set the trace flag 1204 but am not seeing anything in the Error.log and I initiated a trace in profiler which does not seem to show any deadlock. Despite having recreated the problem which show my browser hanging indefinitely. When I run the following queries:
SELECT spid, waittime, lastwaittype, waitresource FROM master..sysprocesses WHERE waittime > 10000 AND spid > 50
SELECT spid, cmd, status, loginame, open_tran, datediff(s, last_batch, getdate ()) AS [WaitTime(s)] FROM master..sysprocesses p WHERE open_tran > 0 AND spid > 50 AND datediff (s, last_batch, getdate ()) > 30 ANd EXISTS (SELECT * FROM master..syslockinfo l WHERE req_spid = p.spid AND rsc_type <> 2)
I get:
55860978LCK_M_XPAG: 13:1:2573
54AWAITING COMMANDsleeping sa 11499 55UPDATE sleeping sa 21499
We have a SQL 2005 transaction database server that suddenly started to issue deadlock errors last week on most of the databases on that server and a lot of timeout errors. Before that, that database server performed very well and timeouts were minimal to zero. I am not sure what changed for it to have these performance problems.
The only major change we did was to convert several varchar columns to nvarchar in several tables (as part of internationalization initiatives). We did not modify the procs from varchar to nvarchar though but would be doing that phase by phase.
There is also one proc in which we used the snapshot isolation level of sql server 2005. These are only 2 major changes done within the past 2 weeks. Would these be the cause for these deadlocks and timeouts on our web-based application?
Hi EverybodyI am new to sqlserver 2000.I know basics of locks.but i dont know how toresolve deadlock issues.I am cofusing by reading articles with 90%information and remaining 10% missing.Can any one help me which is the goodsite to learn and resolve deadlocks.Note: I create deadlock. when i try to trace deadlock using dbcc traceon(1205,3604,-1).In error log showing nothing about the deadlock.showing created traceon.........Any help would be appreciated.--Message posted via http://www.sqlmonster.com
We have a problem with a table giving us deadlock issues and we can'tfigure out why.It's a table we write to fairly often perhaps 50 times a minute. Andalso do a select of 200 rows at a time from 4 servers every 5 minutes or so.We are only keeping 48 hours worth of rows in the table which averagesat 30000 a day on a busy day.This table has 1 PK and 2 FKs plus one TEXT column which does notparticipate in the WHERE clause.We are using binded variables.We have applied the latest patch to SQL2003 server running onWindows2003. The patch is supposed to resolve deadlock issues.Anyone have any advice on how to alleviate this problem.Thanks
Morning All, Am getting the following error from a number of users and am sort of wondering where to start in terms of diagnosing the problem. If anyone could give me any pointers on where to start in diagnosing the issue I would be grateful. "System.Data.SqlClient.SqlException: Transaction (Process ID 282) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction."
I know blocks and Deadlocks are different but how related are they? Seems like when I get reports of deadlocks I always have blocks and the blocks grow as time passes.
My database has been in production for 10 months with no deadlock problems. Three weeks ago I had to restore the database and I am now experiencing several deadlocks. SQL server is suppose to handle this and kill a process to resolve the deadlock but it is not. The deadlock occures on a stored procedure which is a simple select on a table with 187 records. DBCC ran with no problems. Any ideas what might be causing this? Any why is SQL not handling? Your help is greatly appreciated!
I need some help in reducing deadlocks in 6.5 I have tested with `Insert Row Locking` turned off and it reduced the number of deadlocks. What i need to know is if removing the foreign key relationships on tables reduces/eliminates Deadlocks. If any of you have any info on this please let me know.
i have an issue regarding the following error message:
[Microsoft][ODBC SQL Server Driver][SQL Server]Transaction (Process ID ##) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
this is caused on a couple of ASP pages, which are using:
This is happening fairly frequently, which can't be a good thing, so would it be worth changing the lock or cursor types to a different one, in particular, adLockPessismistic?
Any pointers or comments would be very welcome.
This is happening on a windows server os, sql server 2000 using classic asp (.asp) pages, connecting to sql server using ado within the asp pages.
I have a search function, which searches across many tables.
It's a pretty heavy SPROC, I'm wondering in general, what are the best way to reduce deadlocks ? Its used a fair bit, and altho I haven't noticed problems with it myself, there are definately a decent amount of deadlocks showing up in the logfiles.
I've always assumed this is something really difficult, and avoided it like the plague.
I'm going thru my application log, and just seeing what errors are popping up. I have a relatively intense search feature, thats causing alot of deadlocks.
Exception type: SqlException Exception message: Transaction (Process ID 105) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
In general, what's the best way to resolve this ?
Should I see if I can apply "WITH (NOLOCK)" to my data ?
Problems in a 2008 R2 environment, database grows quickly and deadlocks occure somtimes.When I checked the database the tables lacked completely of indexes.How can I find out which indexes that should be created and how to manage the deadlocks?
I face alot of DeadLocks in my SQL Server. the server is SQL 2000 SP3 with Windows 2000 sp4. I have all kinds of locks and i really don't understand none of them. I tried to restart the server and it didn't help - the locks id and locks objects are still there - about 15 objects. what to do?
I'm trying to diagnose deadlocks in SQL Profiler. The deadlocks weregenerated by Loadrunner scripts (stress testing) simulating applicationSQL via an ODBC DSN connection.2 things are puzzling me in the SQL Profiler traces that I have logged1) There are a large number of Lock:Timeout events but the 'locktimeout' setting is the default 'wait forever' so I dont know what istiming out.2)When say 2 distinct SPIDs are in a Deadlock Chain, they are using thesame ClientProcessId at the time of deadlock. What is theClientProcessId and is it relevant to the deadlock?Thank you in advance for any replies.
I am getting lot of deadlocks in my application. As it is very complexti avoid deadlocks at this stage of application we have done few stepsto lessen the impact.We have added retries after deadlock is capturted.We have added select * from TABLE with (nolock) wherever possible.But interestingly second step is not working. I have few simple selectstatements where i am using nolock criteria still I am gettingdeadlock victim error. Any idead why it happening. I thought as soonas I put nolock in the query it will ignore all the locks.My sp isCREATE procedure sp_Check_denomination@supply_till_idint,@product_codechar(4),@iso_currency_codechar(3),@denominationmoneyasdeclare @product_id numeric(5)select @product_id = product_id from product with (nolock) whereproduct_code = @product_codeif exists (select *from transaction_inventory TI with (nolock),product_ccy_denom PCD with (nolock)where TI.supply_till_id = @supply_till_idand TI.product_id = @product_idand TI.iso_currency_code= @iso_currency_codeand TI.denomination = @denominationand TI.product_id = PCD.product_idand TI.iso_currency_code = PCD.iso_currency_codeand TI.denomination = PCD.denominationand PCD.product_id=@product_idand PCD.denomination = @denominationand PCD.iso_currency_code=@iso_currency_codeand PCD.tradeable = 1)beginreturn(1)endelsebeginreturn(0)endGO
