A situation caused by two or more processes being unable to proceed (and thus release their locks) because they are blocked by locks on resources held by the other process.
27
votes
5answers
16k views
What are the main causes of deadlocks and can they be prevented?
Recently one of our ASP.NET applications displayed a database deadlock error and I was requested to check and fix the error. I managed to find the cause of the deadlock was a stored procedure that ...
14
votes
1answer
1k views
Can foreign keys cause deadlocks and hinder READ COMITTED SNAPSHOT?
This is a followup question from: http://stackoverflow.com/questions/7684477/is-it-possible-to-set-transaction-isolation-level-snapshot-automatically
I'm still having deadlock/timout situations in ...
11
votes
2answers
3k views
Code to simulate deadlock
I am testing my application I need some code that stable simulates the deadlock on database site (sql script if possible).
Thank you.
ADDED:
Reproducing deadlocks involving only one table
11
votes
5answers
485 views
Handling concurrent access to a key table without deadlocks in SQL Server
I have a table that is used by a legacy application as a substitute for IDENTITY fields in various other tables.
Each row in the table stores the last used ID LastID for the field named in IDName.
...
11
votes
2answers
933 views
Deadlocks From Locks on Same Temporary Tables In Different Processes
I have found a deadlock that appears to show something I thought was impossible. There are two processes involved in the deadlock:
1. process8cf948 SPID 63
Performing an ALTER TABLE on temporary ...
9
votes
3answers
586 views
Need Help Troubleshooting Sql Server 2005 Deadlock Scenario
I am running into a deadlock scenario where the only participants in the deadlock appear to be a single table and a single stored procedure that deletes from that table. I drew that conclusion based ...
8
votes
3answers
8k views
Notification on long-running query or deadlock in SQL Server 2008 R2?
I'd like to know if there is a way to send a notification on deadlock? If so what queries would be required. I understand that SQL Server takes care of deadlocks, I simply would like information on ...
8
votes
1answer
387 views
Why are there Victimless Entries on the Deadlock Graph?
I am trying to learn how to analyze SQL Server 2008's deadlock graph, and I'm finding alot of entries with an empty <victim-list> node. I don't understand what these entries represent: if there ...
7
votes
1answer
636 views
How are deadlocks detected and reported in an RDBMS?
I was given this essay type question during an interview but did not get the job. The full question was as follows:
How are deadlocks detected and reported in an RDBMS? What are the transaction ...
7
votes
1answer
149 views
What does “*password------------” mean in a profile deadlock report?
In SQL Server 2008 R2, I got several deadlock reports that have "*password------------" in the input buffer. It looks like an attack but in that case I don't know the reason or the kind of attack.
...
7
votes
2answers
322 views
How does SQL Server determine the order it takes locks in while selecting a table?
I have two stored procedures that are deadlocking when the system is under load. Proc A is selecting from a table while the Proc B is inserting into the same table. The Lock Graph is showing that Proc ...
6
votes
2answers
2k views
Why does this query cause a deadlock?
Why does this query cause a deadlock?
UPDATE TOP(1) system_Queue SET
[StatusID] = 2,
@ID = InternalID
WHERE InternalID IN (
SELECT TOP 1
InternalID FROM system_Queue
WHERE ...
6
votes
1answer
1k views
Deadlock error isn't returning the deadlock SQL
Transaction (Process ID) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
I am getting this error randomly when one of my ...
6
votes
4answers
6k views
How to monitor deadlocks
When do you start troubleshooting a SQL Server 2005/2008 deadlocks and how? The alert is turned on SSMS via SQL Server performance condition alert, objects->SQLServer:Locks, Counter->Lock Waits/Sec, ...
6
votes
2answers
1k views
MySQL deadlock - cannot restart normally?
MySQL version 5.5.13-1
A snippet from the SHOW ENGINE INNODB STATUS\G:
LATEST DETECTED DEADLOCK
------------------------
111218 10:22:34
*** (1) TRANSACTION:
TRANSACTION 1318D95B, ACTIVE 0 sec ...
6
votes
1answer
195 views
Deadlock graph with a lock on an index on a seemingly unrelated table
I have a deadlock graph from a deadlock where one process is doing a SELECT and one is doing an UPDATE. This seems like the classic case where the SELECT gets a NCI lock to perform a join and then a ...
6
votes
2answers
2k views
Trouble deciphering a deadlock in an innodb status log
We are accessing MySQL from the Microsoft ADO.NET connector.
Occasionally we are seeing the following deadlock in our innodb status and haven't been able to identify the cause of the problem. It ...
6
votes
3answers
420 views
Inserting and updating and selecting at thousands of times per second
I have a table that gets inserted, updated and selected from thousands of times within one second. I am having deadlock issues though.
The database has 2-5 simultaneous 1000+ row inserts using Linq ...
6
votes
1answer
272 views
Deadlock on Merge replication
I'm having a really confusing problem on the msmerge_contents table on some
of my merge replication databases. It seems I'm receiving a dead lock on the exact
same row on the same index on the table ...
5
votes
3answers
2k views
SQL Server 2008 merge statement deadlocking itself
I have the following procedure (SQL Server 2008r2):
create procedure usp_SaveCompanyUserData
@companyId bigint,
@userId bigint,
@dataTable tt_CoUserdata readonly
as
begin
set ...
5
votes
1answer
2k views
SQL Server Deadlock Graph - Table, Page or Row Lock?
Is there any way to decipher if a lock in a deadlock graph is Table, Page or Row level? I have all the information I need from the graph, including the Isolation Level, (2) but I really want to know ...
5
votes
1answer
262 views
SQL Server Deadlock on two updates due to index lock order
I have two UPDATEs - one locks the CI first and then the NCI (on status) because the status column is also being updated. The other already owns a U lock on the NCI because it knows it is changing ...
5
votes
2answers
42 views
Given two known statements, how can I replicate deadlock?
I have two statements (an update against every row in one table (call it table A) and a delete on another table that looks up rows in table A) that I know are causing occasional deadlocks. It seems ...
5
votes
1answer
2k views
Are InnoDB Deadlocks exclusive to INSERT/UPDATE/DELETE?
I am Working around MySQL error "Deadlock found when trying to get lock; try restarting transaction".
I am going to have to update a program to allow deadlocks. Is it possible that SELECT statement ...
5
votes
2answers
158 views
SQL Server Select Count READ_COMMITTED_SNAPSHOT QUESTION
I seem to be getting a lot of deadlocks when doing select count(*) on a particular table.
I have already changed all the required parameters and made them into row only locking.
I've also changed the ...
4
votes
3answers
513 views
Is Oracle DB immune to the InnoDB deadlocks found in MySQL?
It seems odd to me that MySQL would not handle this internally: "Deadlock found when trying to get lock; try restarting transaction"
Does Oracle DB work around this issue? After all, Oracle owns ...
4
votes
2answers
521 views
Oracle 11g see transaction or session start time
I want to know when a session or transaction started. The deadlock file doesn't give me this information. Is there some logfile that keeps these records?
I've got a transaction id "TX-1234-abcd", a ...
4
votes
3answers
2k views
How to make sure that simultaneous INSERT and SELECT on one table won't make a deadlock?
I have the following table in my SQL Server 2008 database:
CREATE TABLE [dbo].[SomeTable]
(
[Id] [bigint] IDENTITY(1,1) NOT NULL,
[Column1] [varchar](30) NOT NULL,
[Column2] [varchar](30) ...
4
votes
2answers
2k views
Determine Reason for Deadlock in MySQL
We've been seeing some deadlocks occur but have not been able to reproduce. Is there any way to determine, after the fact, what queries were running, etc to figure out why deadlock occurred?
4
votes
2answers
232 views
How do I query only for committed data while avoid a deadlock
I have a system writing batches of queries as transactions (to maintain coherency), these can be sets of 30-100 queries per transaction. These are done on multiple tables
At the same time there are ...
4
votes
2answers
4k views
can I resolve a deadlock with the rowlock hint?
I have a large delete stored proc and I've reproduced a deadlock in a situation where the deletes would not have deleted anything.
It looks like the part of the stored proc that hit a deadlock was ...
4
votes
2answers
2k views
Will these two queries result in a deadlock if executed in sequence?
This is almost certainly the cause of my other question, but I thought it was worth separating the two as I have a hypothesis based on the following log that I would love to have falsified or ...
4
votes
2answers
140 views
Deadlock during Slony uninstall and concurrent access of DB
I am using slony1-2.0.4.rc2 and postgresql-8.4.0-0. I faced a deadlock in the slony uninstall process.
I was trying to uninstall node from a cluster, as per slony's documents this requires access ...
4
votes
2answers
1k views
How to handle deadlock issue sql server 2008?
I have a simple application.This application update data of a table (B) from another table(A) which is changed every 60 sec. User may read data at any time so creating deadlock. How is this sort of ...
4
votes
0answers
96 views
After 5 years of working, SQL Server 2k5 Table now locking without any changes made to DB
I have a table: OrderDetails.
For 5 years, only the odd Deadlock has occured.
If it happened, it happened on indexes which was on OrderDetails table
Now all of a sudden, deadlocks are everywhere - ...
3
votes
3answers
326 views
Why am i getting deadlocks with 1 read and 1 write thread in SQL
if anyone could please help me understand why the following transactions deadlock?
I am providing the 2 transactions and the indexes for each table:
Transaction 1:
SELECT blockId, blockData, ...
3
votes
2answers
424 views
SELECT/INSERT Deadlock
This instance hosts the SharePoint 2007 databases (SP). We have been experiencing numerous SELECT/INSERT deadlocks against one heavily utilized table within SP content database. I have narrowed down ...
3
votes
1answer
310 views
How to force the use of row locks?
I am trying to get my table to use row locks. I have already disabled lock escalation. The isolation level is READ_COMMITTED_SNAPSHOT
alter table <TABLE_NAME> SET (LOCK_ESCALATION=DISABLE)
go
...
3
votes
3answers
228 views
Does Snapshot Isolation only give you what has been commited? (And General Snapshot Isolation questions.)
So, I have some deadlocking issues.
I have seen two options to resolve it. Add read uncommitted to my db or do Snapshot Isolation and add read committed snapshot.
After doing some research into ...
3
votes
1answer
159 views
Deadlocks on same wait resource
I am experiencing a deadlock in SQL Server, but I do not understand why this is a deadlock. It looks like the two resources are actually the same. Meaning that they each have the lock and are asking ...
3
votes
2answers
3k views
How to debug deadlocks in SQL Server 2008 R2?
I'm using SQL Server 2008 R2 that automatically lock database items based on my queries.
Sometimes this deadlocks - two threads with different queries never ends.
Is there any way to debug how SQL ...
3
votes
2answers
255 views
Lock escalation problem on a trigger
I've inherited a SQL Server 2005 database that is getting 2-3 deadlocks a day.
I've tracked it down to a scheduled job that runs during the day and inserts into a table with a trigger.
The trigger ...
3
votes
1answer
92 views
Deadlock between two databases
I have my code running online shared hosting provider. Recently I am seeing too many deadlock exception is being thrown. As you know that shared hosting uses the same database server to host all the ...
3
votes
1answer
2k views
Oracle 11g hunting down the deadlock, maybe foreign key?
I am trying to understand why a deadlock occurs in my database. The trace tells me that two updates on the same table are locking. In table is the first table to be written to in an transaction, only ...
3
votes
1answer
97 views
How this simple Stored Procedure ended up in Deadlock
Thanks for all and this forum is really helpful.
After few minutes of system running we get “Try restarting the transaction.”
And its end up in deadlock.
We use MySQL 5.5.28 and the Java code ...
3
votes
1answer
182 views
All-or-none exclusive lock on 2 SQL tables
My simplistic testing suggested that I can acquire an exclusive lock on 2 tables or postpone acquiring the lock on either until both can be acquired at once by using a query like this:
SELECT ...
3
votes
2answers
420 views
Cannot update certain rows in innodb tables
I found the following on http://dev.mysql.com/doc/refman/5.1/en/innodb-deadlock-detection.html
When InnoDB performs a complete rollback of a transaction, all locks set by the transaction are ...
3
votes
1answer
375 views
Deadlocks in SQL Server
We're currently encountering a problem with out ASP.NET Application that results in deadlocks on the SQL Server database. A bit of background information I can provide is that we rely heavy on AJAX ...
3
votes
2answers
1k views
Shared and IX locks causing deadlock (Sql server)
In my environment, I have 2 tables - Issue and IssuePropertyValues (which has foreign key reference to the Issue table).
Now, we insert values into these 2 tables using the below 2 queries:
INSERT ...
3
votes
1answer
1k views
How to find out what caused the database(DB2) in a locking state
I know how to check the DB is in a lock state or not, but my question is how to find out which query caused the lock on table /db.
IS there any log file getting created if something unexpected ...
