T-SQL (SS2K8) :: Avoid Blocking And Deadlock
Jun 4, 2015How we can avoid blocking and deadlock?
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Unable To Avoid The Deadlock
Oct 11, 2007Hi,
Please help with the below deadlock problem :
We are using SQL Server 2000. Our application is a J2EE based. We use Java v 1.5 ,EJB 3.0 ,JBoss-4.2.0 and have sqljdbc.jar v 1.1 driver (to connect to sql server from jboss).
We have a JMS Queue which is unloading a java.util.List object at a time. This List has 5 value objects.
In the session bean I iterate through this list and do the following :
while(importListPeople.hasNext()){
Person value = (Person)importListPeople.next();
//select statement to check if the Person already exists in DB
Person prsn =entityManager.query("SELECT from Person where...");
if(prsn !=null){ //do an update if person already exists
// update person record
// update PersonAV table
// do an insert into personIndexingQueue
// increment the person update counter.
}else{//do a create
entityManager.persist(value);
//insert into personAv table
//do an insert into personIndexingQueue
//increment the person create counter.
}
}
I get the below error when we are running the application
13:04:41,904 WARN [JDBCExceptionReporter] SQL Error: 1205, SQLState: 40001
13:04:41,904 ERROR [JDBCExceptionReporter] Transaction (Process ID 63) was deadlocked on {lock} resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
For log ,sqlprofiler I could narrow down that the deadlock is occurring on the below select statement in the code.
//select statement to check if the Person already exists in DB
Person prsn =entityManager.query("SELECT from Person where...");
This code works if there is only one object in the list.
The above code works on mysql with 20 objects in the list.
Please help.
How To Avoid Deadlock With Simple Update Statements
Aug 29, 2007I searched a bit but didn€™t get too far in actually solving a case of deadlock in a simple query I have running here. The queries in question are executed under 2 separate transactions (Serializable IsolationLevel) and are shown below. I guess I don€™t understand how those 2 can deadlock because they are operating on different rows of the table and Serializable should keep them isolated pretty well too. Is it because I€™m using the column value inside an update stmt? How should this query be split if that€™s the case?
This is what the SQL Profiler has to say:
Lock: Deadlock Chain Deadlock Chain SPID = 59
Lock: Deadlock Chain Deadlock Chain SPID = 57
Lock: Deadlock my_user_name
57: UPDATE CreditCard SET Balance = Balance - 200 WHERE (Account = 0 AND CardHolder = 'Foo' AND Balance - 200 >= 0)
59: UPDATE CreditCard SET Balance = Balance - 250 WHERE (Account = 3 AND CardHolder = 'Bar' AND Balance - 250 >= 0)
I also used DBCC TRACEON(1204, 3605, -1) but I don€™t understand what the SQL log is telling me. Can anyone shed some light on why the above 2 statements sometimes cause the following:
System.Data.SqlClient.SqlException: Transaction (Process ID 57) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
I really don't want to retry the update if I don't have to. Table looks like:
Column DataType Length
Account int 4
CardHolder char 64
Balance float 8
T-SQL (SS2K8) :: Avoid LEFT Join
Aug 20, 2013I am facing issues with a LEFT JOIN in my query. It takes 45 secs to process on the production server due to huge number of records.building a query to avoid the LEFT JOIN. I am Trying to use UNION ALL and it works much faster except that I am stuck in the last bit.
scripts (sample):
CREATE TABLE [dbo].[tbl_PersonDetails](
[PersonID] [int] NOT NULL,
[LeaveTimeId] [int] NOT NULL
) ON [PRIMARY]
[code]...
Need Rows from tbl_PersonDetails macthing (all 3 below) following criteria :
1. tbl_PersonDetails.PersonID is present in tbl_PersonLeaveDetails
2.tbl_PersonDetails.TimeID does not fall between any of the aligned (matching personid) FromTimeID and ToTimeID in tbl_PersonLeaveDetails.
3. not using LEFT join
T-SQL (SS2K8) :: Deadlock When Creating New FK Constraint?
Sep 17, 2015The other day developer asked me to create a new table that had a FK constraint to an existing largish table on the largish table's primary key.
When i ran the script, it took it about 4 seconds to complete, and in the meantime i had 3 deadlocks show up from other processes attempting to use the table the FK was being created from. The new table was empty at this point.
I've never seen this behavior before so I'm curious if creating a new FK constraint will cause a table lock on the source table for the FK.
T-SQL (SS2K8) :: Query To Avoid Duplicate Records (across Columns)
Jan 3, 2015rewrite the below two queries (so that i can avoid duplicates) i need to send email to everyone not the dup[right][/right]licated ones)?
Create table #MyPhoneList
(
AccountID int,
EmailWork varchar(50),
EmailHome varchar(50),
EmailOther varchar(50),
[Code] ....
--> In this table AccountID is uniquee
--> email values could be null or repetetive for work / home / Other (same email can be used more than one columns for accountid)
-- a new column will be created with name as Sourceflag( the value could be work, Home, Other depend on email coming from) then removes duplicates
SELECT AccountID , Email, SourceFlag, ROW_NUMBER() OVER(PARTITION BY AccountID, Email ORDER BY Sourceflag desc) AS ROW
INTO #List
from (
SELECTAccountID
, EmailWorkAS EMAIL
, 'Work'AS SourceFlag
FROM#MyPhoneList (NoLock) eml
WHEREIsOffersToWorkEmail= 1
[code]....
T-SQL (SS2K8) :: Reading A Control Table - Avoid Using A Cursor
Jan 21, 2015I am trying to think of a way to read a control table, build the SQL statement for each line, and then execute them all, without using a cursor.
To make it simple... control table would look like this:
CREATE TABLE [dbo].[Control_Table](
[Server_Name] [varchar](50) NOT NULL,
[Database_Name] [varchar](255) NOT NULL,
CONSTRAINT [PK_Control_Table] PRIMARY KEY CLUSTERED
[Code] ....
So if we then load:
insert into zt_Planning_Models_Plant_Include_Control_Table
values ('r2d2','planing1'), ('r2d2','planing7'), ('deathstar','planing3')
Then you would build a SQL script that would end up looking like the following (note all the columns are the same):
insert into master_models
Select * from r2d2.planning1.dbo.models
insert into master_models
select * from r2d2.planning7.dbo.models
insert into master_models
Select * from deathstar.planning3.dbo.models
Mirroring :: Email Deadlock Information When A Deadlock Occurs
Nov 10, 2015Is there a way to send out an email woth deadlock information (victim query, winner query, process id's and resources on which the deadlock occurred) as soon as a deadlock occurs in a database or at instance level?I currently has trace flag 1222 turned on. And also created an alert that send me an email whenever a deadlock occurs. but it just says that a deadlock occurred and I log into sql server error log and review the information.
View 5 Replies View RelatedBlocking
Aug 15, 2000One sql transaction is in rollback state and optimization job is trying to restructure index on the same table that this transaction is using. As a result,
transaction is in 'blocking' state and optimization job is in 'blocked' state. 'Kill process' doesn't do anything. How can this situation be resolved?
Blocking
Nov 26, 2001Is it possible that blocking can occur between a select and update statements running at the same time on the same object??thanks for the reply!
Sheila.
Self Blocking SP4
Nov 1, 2007Anyone out there having "self blocking" issues since upgrading to SP4 on SQL 2000? Enabing trace flag 9059 has not helped, is this a parallelism issue ?
thanks,
Paul
Blocking When Doing Bcp
Jan 6, 2004Any ideas?
I execute a sproc from QA.
It interogates a folder:
Select @Command_String = 'Dir ' + @FilePath + '*.txt'
Insert Into XLAT_Folder exec master..xp_cmdshell @Command_String
[/code[
Which I then Parse and get the details...
Set up a CURSOR (Booo hiss....)
[code]
DECLARE XLAT_Folder CURSOR FOR
SELECT Create_Time
, File_Size
, [File_Name]
FROM XLAT_Folder_Parsed
ORDER BY [File_Name]
WHILE FETCH STATUS = 0
BEGIN
BEGIN TRAN
Then, based on the methodology that the file name must match the table and format file (I check to make sure everything is out there)
I then bcp the data in using my connection pooling id (I'm logged on as sa in qa)
SET @cmd = 'bcp ' + @db_name + '..' + SUBSTRING(@File_Name,1,CHARINDEX('.',@File_Name)-1) + ' in '
+ @FilePathAndName
+ ' -f' + 'd:DataTax' + SUBSTRING(@File_Name,1,CHARINDEX('.',@File_Name)-1) + '.fmt'
+ ' -S' + @@servername + ' -U -P'
SET @Command_string = 'EXEC master..xp_cmdshell ''' + @cmd + '''' + ', NO_OUTPUT'
INSERT INTO #XLAT_BCP_Results(Col1) Exec(@Command_String)
MOVE DATA FILE TO ARCHIVE
COMMIT TRAN
ANOTHER FETCH
A spid is launched to do the bcp...I have 4 files...on the last load The connection Pooling lauched spid gets blocked by the sa spid that launched the sproc...it doesn't happen all the time, just most of the time....
I've put a trace on in Profiler, but I don't see anything...I've picked the event class of deadlocks...but I never see it...
When I do sp_who, it shows the blocking...
I'm so confused....
Blocking
Aug 31, 2006Hi just read an article on the internet that states
"A quick way to resolve a blocking problem is to disconnect the connection blocking the rest of the users. All you have to do is ask your database administrator to execute the KILL statement. Obviously, this is not a permanent solution, and won't really help anything except take care of an immediate need."
Now when i run sp_who ... i see that the spid that is blocking is the same as the spid itself....
Now the above article states that killing the one that is blocking the rest of the other spids is ok ...
But what if its the same SPID that is blocking ...what does it signify & whats the solution
Thanks
Blocking
Nov 13, 2007Hi Gurus,
I am running a simple SELECT statement on my TempDB
SELECT * FROM TempDB..SysObjects
When I run this , it's getting blocked by some other Process which is not at all relevant to the above Qry. First it gets blocked by one Stored Proc say Proc1 ( The Proc1 is just a SELECT statement on a table which just has four rows ). So I just kill this PROC1 and again its gets blocked by some other stored Proc PROC2 which again is a simple stored Proc and it runs in not time.
Any Suggestions as to where to start.
Thx in Advance
Venu
Blocking
Jul 23, 2005hi,I am using SQL SERVER 2000.Problem that i am facing is when ever I check locks in EnterpriseManager I findfollowing blocking - :1) sp_cursoropen;12) sp_cursorclose;13) sp_cursorfetch;1We dont have any control over application(source code).Whateverwe have to do, has to done from database side.can anyone guide me to solve this problem.Thanks
View 4 Replies View RelatedSql Blocking Problem
Dec 13, 2007I have one batch jobs running 4 time a day and web application.
We have hosted the site long time already but this month we are facing the store procedure blocked problem.
The problem is that when user submit the form when during the execution of batch job, two storeprocedure are blocked.
One store procedure that is using from batch job read the table "A" and another store procedure that is using from web app update the table "A".
Then deadlock is occure. but i don't understand it is hosted long time already. Please let me know if you know how to solve this issue.
Thanks,
Aung
Blocking URGENT!!
Jan 14, 2002Hi ALL!
Can a sleeping process block another process sleeping/runnable?It's happening in our SQL server.Can someone expalin??
thanks.
Di.
SQL Server 7 Blocking
Apr 24, 2002I have a powerbuilder application that is connecting to SQL Server. We get very frequent DeadLock situations. Is there a way that I can check to see as what SQL is causing the Lock?
Thanks in advance for any suggestions...
-Raj
Blocking Processes
May 29, 2001I have upgraded a MS SQL database from 6.5 to 7.0. The database functioned fine in 6.5, now I have a table that is locking due to a blocking process. If I kill the process all is fine, but am trying to determine what is causing the process to hang. Has anyone experience any similar situations.
View 2 Replies View RelatedBlocking (Urgent)
Jul 10, 2001Hello,
In the morning at 9:32 one of the spid was blocked and got time out msg for select statement. the statement was sp_execute wht is sp_execute?
can anyone guide me?
Thanks
Blocking (Urgent)
Jul 13, 2001Hello,
I've a problems with blocking
simple select * from table1
is blocked
how to know which statement is blocking
select * from table1 is spid 30 blocked by spid 26
and in current activity spid 26 has no select or any statement
how could i know the spid 26 statement ?
And can just select statement be blocked?
wht should we do to monitor locks?
Thanks
Binoy
Spid - Blocking
Nov 15, 2000I know that spid 22 is blocking 2 other users. How do I tell who that user is? Is this just matching the same spid# in the process info in EM and if it doesn't give me an NT name it's probably because they're coming through the application and I can't figure it out?
Thanks
Blocking Problem.
Feb 4, 2001Hi there,
I've a encountering a problem with "Blocking" and would highly appreciatd, if anyone out there please advice how to get to the bottom of this. the problem in as follows:
Every now and then, my SQL Server Freezes and when i look at the process info, i see some user connections in blocked mode and some in blocking. i dont know, where to start looking for. my first question would be, what should I do here? Should i kill the blocked user or blocking user? Also, Whats the difference between this two modes (blocked and blocking) and why does this happening? can i trace the user id which is causing this problem?
Experts please advice, what to do in the near future to aviod this.
I search at microsoft support site and came up nothing good about this problem.
Appreciated, If anyone out there advice on this.
Many thanks in advance.
Sindi
Blocking Problem
Apr 19, 2000When an SA attempts to change permission on any object they are shown as blocked as expected. However as new users access the object the SA's process is continuely blocked until the object is free. Can anyone explain this??
Thanks
David
Blocked/Blocking
Dec 7, 1999Hello...
Is it normal in SQL Server 6.5 the user who only running the query blocking the other user who try to update/add the records?
note: The query is a complex SQL.
Many Thanks!
Insert Blocking...
Jun 2, 2005found many blocking on SQL2000 enterprise by insert statement, the same insert statement failed in the sql/w with violation on the primary key.
however, the appl insert also got the same error from log, but still in 'blocking' instead of to be 'killed' by the pk violation.
what would be the options to deal with this issue?
thanks
-D
Blocking Issue
Nov 17, 2005Please advice.
I have a sql2K SP3 active/passive failover cluster running on W2K SP4. I epxerienced a blocking scenario. The blocking process was killed only to find another process cause blocking. Killing the blocking process didn't resolve the blocking issue.
Eventually I had to fail over the SQL Server instance to another node and that brought resove the blocking issue.
What direction should I look for investigation and solution.
URGENT PLEASE.
Help appreciated
Blocking Problem
Aug 24, 2001I have a vendor supplied database which seems to have a simple blocking problem. The blocking will occur when a user tries to delete from a table where another user might be inserting or selecting from. The table has only 3 columns and the delete statement looks fine. (they are not deleting the same record) This is on SQL 2000 sp1. has anyone seen this or have any ideas. The db is on a fast server (quad 2 gig of ram). I did have the thought on a problem I ran into with an older db on SQL 7 where the write-ahead RAID controller was actually causing a simlar problem. Any help appreciated
View 2 Replies View RelatedBlocking Sa User
Dec 8, 2006Hi All,
I have a hypothetical scenario. I have few developers who all know the sa password. I want to block one developer from accessing the SQL server eventhough he knows the sa password.
Do we have any mechanism in SQL Server 2000 to block client based on the IP address of the client?
SQl Server is installed on Windows 2000 server. It uses SQL Server & Windows authentication.
Regards,
Anand
Odd Blocking Issue
Sep 4, 2007I don't understand why a CREATE PROC from 3.5 hours ago is the head blocker. The SP wasn't changed since in months so this must be a compile/recompile? It's not a COMPILE lock though but a PAGE lock. It's certainly not the initial creation. What else can be done to debug this? It's happening and usually resolving itself in 4-6 hours or if I kill the head blocker myself. It doesn't happen every day but almost every day.
I've retrieved this info about the blocking from DMVStats and found similar info using my regular blocking info script also pulling info from DMV's.
I'm running SQL 2005 SP2 Enterprise.
statement started 6:35AM
waiting statement (PAGE lock):
insert into grades (blah,blah)
select blah blah from homework join blah blah
statement started at 3:01AM
blocking statement: =============================================
-- Author: <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================
CREATE PROCEDURE [dbo].[ResultsHomeworkDelete]
@homeworkResultId int,
@NumDeleted int output
AS
delete homeworksessions where homeworkresult_id = @homeworkresultId
set @NumDeleted=@@ROWCOUNT
delete homeworkresults where homeworkresult_id=@homeworkresultId
set @NumDeleted=@NumDeleted + @@ROWCOUNT
Blocking And Transactions OK?
Sep 23, 2005I'm wondering if I'm doing this right. Wondering about the transactionsand error handling. (Do I even need to put BEGIN TRANSACTION ANDCOMMIT TRANSACTION in there?)I think that this sproc is causing occasional blocking:Alter Procedure sprocINSERTSTUFF@Col1Data int = Null,@Col2Data nvarchar(255) = Null,@Col3Data ntext = Null,@UniqueID int OUTPUTASset nocount onset xact_abort onDECLARE @err intDECLARE @ServerDate DateTimeSELECT @ServerDate = GETUTCDATE()BEGIN TRANSACTIONINSERT INTOtblStuff (Col1, Col2, Col3, DateCreated, etc.)VALUES(@Col1Data, @Col2Data, @Col3Data, @ServerDate, etc.)SELECT @err = @@error IF @err <> 0 BEGIN ROLLBACK TRANSACTION RETURN@err ENDSELECT @UniqueID = SCOPE_IDENTITY()COMMIT TRANSACTIONBEGIN TRANSACTIONINSERT INTOtblMoreStuff (UniqueID, DateCreated, Col1, Col2, Col3)Values(@UniqueID, @ServerDate, @Col1Data, @Col2Data, 'Text Label: ' +isnull(Cast(@Col3Data AS nvarchar(4000)),'<none>')SELECT @err = @@error IF @err <> 0 BEGIN ROLLBACK TRANSACTION RETURN@err ENDCOMMIT TRANSACTIONSELECT @err = @@error IF @err <> 0 RETURN @err
View 9 Replies View RelatedMOM Blocking Analysis
Oct 19, 2005MOM contains its own Block Analysis script. It is a script written onVB, that looks for the monitored servers, creates for each oneMomCreateObject("SQLDMO.SQLServer"), afterwards connects to eachdatabase on each server and executes SELECT GETDATE() query. If MOMdoesn't receive answer for 6 minutes, it sends alert. Several timessince I started to monitor my servers I received the next alert:The program "SQLDMO_789" has been blocked for 6 minutes on databaseBurstingDataWarehouse in the SQL instance MSSQLSERVER. The definedacceptable blocking threshold is 1 minute(s). "SQLDMO_789" is runningon SPID 134 as login NT AUTHORITYSYSTEM and is blocked by SPID 133.The resource id is KEY: 10:2:1 (a2007950f190)SQLDMO_789 - is the MOM itself (number varies from time to time). 10 -is BurstingDataWarehouse database. As far as I can judge, MOM connectsto the server succesfully (otherwise, how can it know SPID?) The serveritself worked fine at that time - nothing unusual, all the jobsfinished succesfully including the heavy ones. What can block SELECTGETDATE() query for 6 minutes???
View 1 Replies View RelatedCascading Blocking ?
Jul 20, 2005We have a situation that occurs every so often with blocking ofvarious databases on one server (Win200 SQL7). It appears to happen atrandom, so I'm assuming it originates from something a user does andnot a regularily run process.We've examined the data available to us and used the very helpfulblocking code on http://www.algonet.se/~sommar/sqlutil/aba_lockinfo.html(Thanks Erland).Were getting closer to finding the problem, but need some advice onwhat to look for.This is a bit of guesswork, but we suspect that we get into asituation where blocking takes places, and this then cascades to otherprocesses which then block others in turn. The original culprit thenfinishes, but the blocks continue as the newer processes are holdingsomething else up. A bit like dominoes. It seems to take a while tofree this up.The problem we have is determining the start of this process. Once weare made aware of blocking issues, we can find out who is doing what,but almost always get a different answer/user and think we're gettingto it a little late.Ideally, I want to log the blocking somewhere so I can examine thefiles when this occurs and can therefore establish a pattern etc...Any ideas or suggestions would be welcome.
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