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.

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2
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1answer
103 views

Avoiding Deadlocks

We currently have a trigger-based system in place that does the following: When records in certain tables are modified, a trigger fires that makes a field NULL in a varying number of records in ...
0
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1answer
163 views

SQL Server 2008R2 - Stored Procedure with 2 updates causing deadlocks

I have a web api web service that calls an authentication stored procedure. This stored procedure calls a different stored procedure that does 1 update: UPDATE ...
4
votes
1answer
2k views

How I prevent deadlock occurrence in my application?

I am developing an LMS application in PHP framework(Codeigniter 2.1.0). I am using MySQL database. All the tables in the database have innodb engine. I also created indexes on each tables. Now I am ...
0
votes
0answers
31 views

Why are there more MySQL deadlocks on my 8-core machine than 16-core?

I'm running a bunch of scripts in parallel that do: START TRANSACTION REPLACE INTO... REPLACE INTO... REPLACE INTO... ... COMMIT On my 8-core machine, where 8 of these processes are running in ...
2
votes
2answers
178 views

Reducing deadlocks with update query hint or other method

I'm getting 20-30 deadlocks per day on the same table. (2 mil rows) Profiler DeadlockGraphs show KEY LOCK and PAGE LOCK (See attched jpg) Total datatype size per row = 114 bytes We have multiple ...
2
votes
1answer
183 views

How to use proper hints for Upsert involving a top 1 subquery

For this specific case (tracking Load Balancer switches) we wish to optimize an Upsert so that it does not exhibit any race conditions, cause any PK violation, or acquire any over sized locks. ...
0
votes
0answers
83 views

Mysql Deadlock explanation

I have a problem with reading innodb monitor output. It's seem that problem in gap lock on FK_SESSION_CLIENT_ID index. But i can't simulate this situation on dev host. Transaction isolation level is ...
0
votes
0answers
25 views

Indexing and Deadlock in SQL Server 2008? [duplicate]

I am running into a deadlock in SQL Server 2008. Using profiler I was able to determine that the deadlock happens as I am trying to select and update row(s) in table in 2 different sessions. The ...
3
votes
1answer
1k views

PAGELOCK Conversion Deadlock From Update to Intent Exclusive

A customer of ours is experiencing frequent deadlocks. The deadlocks are mostly on the same UPDATE statement. The deadlocks follow a pattern in which both SPIDs have acquired an update (U) lock on a ...
1
vote
3answers
126 views

Keeping an eye on contention

In SQL Server, I am using the following command to see blocked sessions: select * from sys.sysprocesses where blocked>0 This is super. The problem is I need to see what block sessions there ...
4
votes
1answer
258 views

Stored procedure deadlocking itself

I have a strange situation, seen from the log: Process 37278 waits for ExclusiveLock on advisory lock [16421,999999,12864385,2]; blocked by process 53807. Process 53807 waits for ExclusiveLock on ...
1
vote
1answer
573 views

How does locking work in INSERT..ON DUPLICATE KEY UPDATE statements?

I am encountering deadlocks while trying to update multiple rows (a batch) using INSERT..ON DUPLICATE KEY UPDATE. Does MySQL lock all the rows in one batch or does it lock only the row it is updating ...
0
votes
0answers
322 views

Single DELETE statement deadlocking in Sybase ASE

I've got a fairly straightforward process running on ASE 15.7, that creates rows in two tables and later deletes them. The tables are both configured to use datapages for the locking scheme, and the ...
4
votes
1answer
373 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 - ...
0
votes
0answers
80 views

Lock timeouts on a table with two keys, where only one connection writes for a given value of the first key at a time

I have a table user_rollup_message_list that is keyed by (user_id, message_reference). It is a write-heavy table, and gets enough writes that I get many lock timeouts, with a timeout of 50 seconds, ...
3
votes
2answers
463 views

Can 2 tables lock each other if concurrent read/update do not affect same rows? pagelocks off

Can 2 tables cause a deadlock, if the pagelocks are off, and the rows are not related. E.g. Query 1 runs for a few seconds Select * from Orders where CustomerID = 1 and DateOrdered between @D1 and ...
2
votes
0answers
201 views

Read-Commited Snaphsot isolation causing deadlocks?

Our DBA has some type of process setup to monitor deadlocks and sends out an emails when a deadlocks occurs. We have been testing read committed snapshot isolation on our application for a couple ...
2
votes
1answer
2k views

MySQL: Alter Table on very active table gives “Waiting for table metadata lock”

At my work, we've recently upgraded to MySQL 5.5 and since then, have been bitten a few times by the new (and intended) behavior of metadata locking. Basically, whenever we run an ALTER TABLE ...
0
votes
1answer
1k views

Why are these two INSERTs deadlocking? Is it the trigger? What does this deadlock trace 1222 log tell me?

We are seeing intermittent deadlocks in production when receiving multiple simultaneous API requests. Each request basically culminates in an INSERT statement into the same table, which is where we ...
0
votes
1answer
335 views

Deadlock from mysqldump --single-transaction, is it possible?

Is it possible to get a deadlock if you ran mysqldump with the argument --single-transaction ? or any other complication ? If it is used to backup a live site with many other querys running at the ...
2
votes
1answer
2k views

DB2 Communication link failure issue

I would like to get your valuable suggestions for the below problem. My Perl application connects to a DB2 database and keeps inserting data into a table. The application successfully inserts data ...
3
votes
1answer
2k views

SSIS package blocks itself if uses TRUNCATE

There is an SSIS package with Required transaction on the package level and Supported on the tasks level. The main part of the package is deleting the data and inserting new data: Here the Delete ...
1
vote
1answer
201 views

DB2 Insert and Deadlocks

My application has 4 different threads doing inserts into the same DB2 table simultaneously. Could this cause a deadlock / lockwait situtation? Theoretically I don't see a problem here; as one ...
1
vote
0answers
510 views

SELECT + INSERT + Query Cache = MySQL lock up

MySQL server seems to constantly lock up and stop responding on certain types of queries and eventually (after couple of minutes of not responding) give up with an error "MySQL server has gone away", ...
1
vote
1answer
93 views

Increased server load after InnoDB deadlock

I am using InnoDB instead of MyISAM for a couple of months right now, and it has really optimized my game database-wise. I was aware of the danger of deadlocks, but hadn't had any problems with it, ...
-1
votes
0answers
161 views

Postgres database locked up [closed]

I was running a process to update a bunch of rows in postgres database and it locked up. Now I can't select anything out of it. None of my processes are "idle in transaction" when I execute ps ...
-1
votes
1answer
465 views

dead lock when updating [closed]

Update Operation.TrTable Set RecordId = RecordTABLE.newRecordId From Operation.TrTable tr Inner Join ( SELECT r.Id AS newRecordId, r.KeyM AS MappingKey From ...
2
votes
0answers
2k views

Oracle Select Query Over Database Link Suddenly Hangs Endlessly

I have a query that's been in use for years and today it started hanging endlessly. I took the query apart and found the piece causing it to hang is a simple join on a primary key that should run like ...
3
votes
1answer
896 views

Understanding SIX lock in Microsoft SQL-Server

Can somebody explain me how a process can acquire SIX lock on a page? I my deadlock-graph xml file I see that a process running under RC isolation level (executing a select statement at the moment of ...
5
votes
2answers
216 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 ...
4
votes
2answers
1k 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 ...
0
votes
1answer
415 views

Deadlock : Behaviour of NOLOCK

We are running into deadlocks when we run concurrent instances of following query : BEGIN TRAN IF NOT EXISTS (SELECT TOP 1 * FROM Table1 WITH (NOLOCK) WHERE Col1 = Val1 AND Col2 = Val2) BEGIN ...
4
votes
2answers
988 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 ...
0
votes
1answer
352 views

Oracle transactions deadlock

How to rollback all active transactions on Oracle DB? I execute query and see 4 transcations in ACTIVE status. SELECT * FROM V$TRANSACTION
2
votes
1answer
713 views

How can I make a select statement get blocked?

Hello I am trying to intentionally make a SQL select statement get blocked by another simple SQL delete or update statement, for the purpose of learning. I prefer only InnoDB tables. To prepare the ...
2
votes
2answers
755 views

How to rollback the identity seed after deadlock

Now that's an approximate sequence of operations Im performing: SET IDENTITY_INSERT <table-name> ON; INSERT SOMETHING to <table-name> with explicitly specifyed id DECLARE @oldID bigint ...
1
vote
0answers
160 views

Concurrent Access causing deadlock on the same table [closed]

Transaction 1 : SELECT distinct column_id from grid where row_id = @P0 Transaction 2 : INSERT INTO grid (grid_id, row_id, column_id) In this table grid grid_id is primary key clustered. ...
0
votes
1answer
232 views

how to avoid deadlock while updating 2 rows in mysql [duplicate]

This is a interview problem. There is a perl program that updates the database, and it could run in different processes. One process may execute a transaction like: update row A -> update row B -> ...
0
votes
1answer
917 views

postgres deadlock without explicit locking

I use PostgreSQL 9.2, and I do not use explicit locking anywhere, neither LOCK statement nor SELECT ... FOR UPDATE. However, recently I got ERROR: 40P01: deadlock detected. The query where deadlock ...
1
vote
1answer
1k views

Understanding Deadlock graph on one table

I do not understand this deadlock graph that we are experiencing on this table (I have had to redact the exact column names) I have not had much exposure to deadlocks outside of reading material and ...
11
votes
2answers
3k 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 ...
0
votes
1answer
315 views

sql server 2005 deadlock error 3930

I am trying to simulate a solution for a deadlock issue happened on our production server. Run this to create a table to be used in 2 and 3. IF (SELECT OBJECT_ID('dbo.MyProduct') ) IS NOT NULL ...
2
votes
1answer
416 views

When and why can this kind of deadlock occur?

------------------------ LATEST DETECTED DEADLOCK ------------------------ 130409 0:40:58 *** (1) TRANSACTION: TRANSACTION 3D61D41F, ACTIVE 3 sec inserting mysql tables in use 1, locked 1 LOCK WAIT ...
0
votes
3answers
2k views

How to avoid deadlock while updating 2 rows in MySQL

This is a interview problem: There is a perl program that updates the database, and it could run in different processes. One process may execute a transaction like: update row A -> update ...
17
votes
5answers
5k 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. ...
2
votes
1answer
827 views

sp_getapplock doubt

We are using sp_getapplock as a transaction level in a procedure which in turn calls another procedure where again we use sp_getapplock with the same resource names. I wanted to know whether this ...
3
votes
1answer
511 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 ...
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0answers
202 views

Why Am I Getting Deadlock - Please Read Trace

can anyone help me? i'm getting deadlock on this trace, i'm using symmetricds and i can't understand why i'm getting a deadlock on a certain table. I'm using sql server 2008 r2, ...
0
votes
1answer
75 views

Pessimistic locking worst case

We are using Java EE. And are making an apllication where in the worst case, aloot of message queue messages willl come form the same User. Therefore we are looking on Pessimistic, SELECT FOR UPDATE ...
3
votes
1answer
1k 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 ...