Linked Questions

13 votes
4 answers
8k views

MySQL InnoDB locks primary key on delete even in READ COMMITTED

Preface Our application runs several threads that execute DELETE queries in parallel. The queries affect isolated data, i.e. there should be no possibility that concurrent DELETE occurs on the same ...
vitalidze's user avatar
  • 233
7 votes
3 answers
12k views

Concurrent MySQL updates hang with InnoDB (on Amazon RDS)

I'm running into a problem where multiple MySQL updates being performed at the same time will lock up and takes several minutes to finish. I'm using InnoDB, so I'm confused as to why this could be ...
Alan's user avatar
  • 205
11 votes
2 answers
7k 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 verified....
RedBlueThing's user avatar
16 votes
2 answers
8k 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 ...
RedBlueThing's user avatar
8 votes
1 answer
8k 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 ...
700 Software's user avatar
2 votes
2 answers
6k views

How to analyse innodb status on deadlock in insert Query?

I have a dead lock which i have posted here. I managed to get the innodb status from my server. Here is the Innodb status. OS WAIT ARRAY INFO: reservation count 247864, signal count 247470 Mutex ...
Dinesh Kumar Sarangapani's user avatar
3 votes
2 answers
15k views

Innodb UPDATE performance

We recently switched one of our tables to innodb and now we are experiencing very slow UPDATE execution times. An update which used to take 0.010-0.030 seconds can now take over 70 seconds. Some ...
Haluk's user avatar
  • 619
5 votes
2 answers
3k views

Concurrently update with limit mysql

I want to know if concurrently UPDATE .... LIMIT N will not overlap with more than one client querying the db. After UPDATE ... LIMIT N the client will make a SELECT with some client_id assigned. I ...
llazzaro's user avatar
  • 153
6 votes
2 answers
4k 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 ...
quanta's user avatar
  • 1,006
3 votes
1 answer
12k views

Minimize locking on UPDATE with multiple WHERE columns

I have a problematic query that's causing a lock timeout: UPDATE <some_table> SET col1=<some value> WHERE col1 IS NULL AND col2 > <some value> ORDER BY col2 LIMIT 100 ...
Noha's user avatar
  • 133
3 votes
2 answers
5k views

Preventing mysql deadlocks in your php application that uses SELECT… LOCK IN SHARE MODE

If I understand SELECT ... LOCK IN SHARE MODE correctly, you can place it into a mysql transaction to select the rows you will be working with during that transaction. This is done in order to "lock ...
billmalarky's user avatar
5 votes
1 answer
5k views

How do you read MySQL InnoDB Monitor output?

I am new to DB Administration. I am trying to figure out the cause of deadlock exceptions, but I am unable to make sense of the logs. The log says that "transaction 1 is rolled back". Why is this the ...
aleksey sundukovskiy's user avatar
4 votes
2 answers
3k views

Website is too slow when number of records increases?

I have developed a web application called Referral Program, It it developed by using PHP, MySQL. Users can joining the website and when they introduce new members, he/she gets a commission. The system ...
Ashok KS's user avatar
  • 173
4 votes
1 answer
2k views

InnoDB : Deadlock from one reader and one writer

This sort of has me miffed. One query is doing a select that includes a table that is undergoing a heavy UPDATE, but that update takes under 1/2 a second, and there are no other writers to that table....
Don Wool's user avatar
  • 339
0 votes
1 answer
4k views

MySQL InnoDB locking on combined UPDATE-JOIN statements

on querying statements which contain an UPDATE combined with JOIN, we are getting the following errors: Statements writing to a table with an auto-increment column after selecting from another table ...
Daniel W.'s user avatar
  • 103

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