I have searched many threads and stackoverflow but I couldn't found any solution. I am trying to insert records into few innodb tables randomly rather one condition matches which cause whole database down. I am getting this error "Lock wait timeout exceeded; try restarting transaction"
One the question (#1103248) has been answered here
In InnoDB, an insert on an
auto-increment column results in a
table lock. Selecting a row FOR UPDATE
results in a row level lock.
All tables are just used for inserts none of them table performs updated at all. My question is how do I avoid these locks? Is there any solution available?
Here is the solution I found.
I installed the mysql 5.1
I have put following variable in my.cnf innodb_autoinc_lock_mode = 2
Restart mysql all should be set!
Thanks every one for your help.
Related
I am trying to delete several rows from a MySQL 5.0.45 database:
delete from bundle_inclusions;
The client works for a while and then returns the error:
Lock wait timeout exceeded; try restarting transaction
It's possible there is some uncommitted transaction out there that has a lock on this table, but I need this process to trump any such locks. How do I break the lock in MySQL?
I agree with Erik; TRUNCATE TABLE is the way to go. However, if you can't use that for some reason (for example, if you don't really want to delete every row in the table), you can try the following options:
Delete the rows in smaller batches (e.g. DELETE FROM bundle_inclusions WHERE id BETWEEN ? and ?)
If it's a MyISAM table (actually, this may work with InnoDB too), try issuing a LOCK TABLE before the DELETE. This should guarantee that you have exclusive access.
If it's an InnoDB table, then after the timeout occurs, use SHOW INNODB STATUS. This should give you some insight into why the lock acquisition failed.
If you have the SUPER privilege you could try SHOW PROCESSLIST ALL to see what other connections (if any) are using the table, and then use KILL to get rid of the one(s) you're competing with.
I'm sure there are many other possibilities; I hope one of these help.
Linux: In mysql configuration (/etc/my.cnf or /etc/mysql/my.cnf), insert / edit this line
innodb_lock_wait_timeout = 50
Increase the value sufficiently (it is in seconds), restart database, perform changes. Then revert the change and restart again.
I had the same issue, a rogue transaction without a end. I restarted the mysqld process. You don't need to truncate a table. You may lose data from that rogue transaction.
Guessing: truncate table bundle_inclusions
I am running following update -
update table_x set name= 'xyz' where id = 121;
and getting -
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
I googled it number of times and adding extra time to innodb_lock_wait_timeout not helping me out.
Please let me know the root cause of this issue and how I can solve it.
I am using mysql 5.6(master-master replication) on dedicated server.
Also table_x(Innodb table) heavily used in database. Autocommit is on.
Find out what other statement is running at the same time as this UPDATE. It sounds as if it is running a long time and hanging onto the rows that this UPDATE needs. Meanwhile this statement is waiting.
One way to see it is to do SHOW FULL PROCESSLIST; while the UPDATE is hung.
(In my opinion, the default of 50 seconds for innodb_lock_wait_timeout is much to high. Raising the value only aggravates the situation.)
If you give up on fixing the 'root cause' of the conflict, then you might tackle the issue a different way.
Lower innodb_lock_wait_timeout to, say, 5.
Programmatically catch the error when it times out and restart the UPDATE.
Do likewise for all other transactions. Other queries may also be piling up; restarting some may "uncork" the problem.
SHOW VARIABLES LIKE 'tx_isolation'; -- There may be a better setting for it, especially if a long-running SELECT is the villain.
Looks like there is some lock on any of your other transaction. You can check the status of INNODB by using this:
SHOW ENGINE INNODB STATUS\G
Check if there is any lock on the tables like this:
show open tables where in_use>0;
And then kill that processes which are locked.
I have solved the problem. I tried different values for innodb_lock_wait_timeout, also tried to change queries but got the same error. I did some research and asked my colleagues about hibernate.
They were doing numbers of transaction which include updating main table and committing in the end. So, I suggested them to use commit on each transaction. Finally I am not getting any lock wait time out errors.
What's the timeout for mysql LOCK TABLES statement?
Can't find it anywhere.
I tried to set variable innodb_lock_wait_timeout ini my.cnf but it seems it's related to another (row level) locking not to table locking.
Simply it has no effect for LOCK TABLES.
I want to set some low timeout value for case of deadlock, because if some operation will LOCK tables and something will go wrong, it will hang up the whole site!
Which is stupid for example in case of finishing purchase on your site.
My work-around is to create a dedicated lock table and just lock a row in that table. This has the advantage of only locking the processes that specifically want to be locked. Other parts of the application can continue to access the tables even if they are at some point touched by the update processes.
Setup
CREATE TABLE `mutex` (
EMPTY ENUM('') NOT NULL,
PRIMARY KEY (EMPTY)
);
Usage
set innodb_lock_wait_timeout = 1;
start transaction;
insert into `mutex` values();
[... do the real work here ... or somewhere else ... even a different machine ...]
delete from `mutex`;
commit;
Why are you using LOCK TABLES?
If you are using MyISAM (which sometimes needs LOCK TABLES), you should convert to InnoDB.
If you are using InnoDB, you should never use LOCK TABLES. Instead, depend on innodb_lock_wait_timeout (default is an unreasonably high 50 seconds). And you should check for errors.
InnoDB Deadlocks are caught and immediately cause an error. Certain non-deadlocks may wait for innodb_lock_wait_timeout.
Edit
Since the transaction looks like
BEGIN;
SELECT ...;
compute some stuff
UPDATE ... (using that stuff);
COMMIT;
You need to add FOR UPDATE on the end of the SELECT.
I think you are after the table_lock_timout variable which was introduced in MySQL 5.0.10 but subsequently removed in 5.5. Unfortunately, the release notes don't specify an alternative to use, and I'm guessing that the general attitude is to switch over to using InnoDB transactions as #Rick James has stated in his answer.
I think that removing the variable was unhelpful. Others may regard this as a case of the XY Problem, where we are trying to fix a symptom (deadlocks) by changing the timeout period of locking tables when really we should resolve the root cause by switching over to transactions instead. I think there may still be cases where table locks are more suitable to the application than using transactions and are perhaps a lot easier to comprehend, even if they are worse performing.
The nice thing about using LOCK TABLES, is that you can state the tables that you're queries are dependent upon before proceeding. With transactions, the locks are grabbed at the last possible moment and if they can't be fetched and time-out, you then need to check for this failure and roll back before trying everything all over again. It's simpler to have a 1 second timeout (minimum) on the lock tables query and keep retrying to get the lock(s) until you succeed and then proceeding with your queries before unlocking the tables. This logic is at no risk of deadlocks.
I believe the developer's attitude is summed up by the following excerpt from the documetation:
...avoid using the LOCK TABLES statement, because it does not offer
any extra protection, but instead reduces concurrency.
The correct answer is the lock_wait_timeout system variable.
From the documentation:
This variable specifies the timeout in seconds for attempts to acquire
metadata locks. The permissible values range from 1 to 31536000 (1
year). The default is 31536000.
This timeout applies to all statements that use metadata locks. These
include DML and DDL operations on tables, views, stored procedures,
and stored functions, as well as LOCK TABLES, FLUSH TABLES WITH READ
LOCK, and HANDLER statements.
I think you meant to say the default timeout value; which is 50 Seconds per MySQL Documentation it says
innodb_lock_wait_timeout Default 50 The timeout in seconds an
InnoDB transaction may wait for a row lock before giving up. The
default value is 50 seconds
I use a database with an InnoDB-table. When I try to update a row, I get the "ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction" message, which I don't get on any other row (that I've tried).
How can I debug that?
SHOW PROCESSLIST;
is only yielding sleeping processes and because it's an InnoDB table, SHOW TABLE STATUS is basically useless (seems to work only for MyISAM tables).
SHOW ENGINE INNODB STATUS
also does not contain anything useful; the LATEST DETECTED DEADLOCK section contains two transactions from 3 days ago that no longer exist (thread IDs no longer appear in SHOW PROCESSLIST) and no longer seem relevant.
Is there any way to get to know what query caused the problem?
Also I would love to see the current locks on InnoDB tables, what is locking what right now - and not three days ago.
Have you checked the error log file of mysql? Maybe there is more detail to which transaction it is that failed.
To show all tables that are in use, simply execute this syntax
SHOW OPEN TABLES WHERE IN_Use=1
I am trying to delete several rows from a MySQL 5.0.45 database:
delete from bundle_inclusions;
The client works for a while and then returns the error:
Lock wait timeout exceeded; try restarting transaction
It's possible there is some uncommitted transaction out there that has a lock on this table, but I need this process to trump any such locks. How do I break the lock in MySQL?
I agree with Erik; TRUNCATE TABLE is the way to go. However, if you can't use that for some reason (for example, if you don't really want to delete every row in the table), you can try the following options:
Delete the rows in smaller batches (e.g. DELETE FROM bundle_inclusions WHERE id BETWEEN ? and ?)
If it's a MyISAM table (actually, this may work with InnoDB too), try issuing a LOCK TABLE before the DELETE. This should guarantee that you have exclusive access.
If it's an InnoDB table, then after the timeout occurs, use SHOW INNODB STATUS. This should give you some insight into why the lock acquisition failed.
If you have the SUPER privilege you could try SHOW PROCESSLIST ALL to see what other connections (if any) are using the table, and then use KILL to get rid of the one(s) you're competing with.
I'm sure there are many other possibilities; I hope one of these help.
Linux: In mysql configuration (/etc/my.cnf or /etc/mysql/my.cnf), insert / edit this line
innodb_lock_wait_timeout = 50
Increase the value sufficiently (it is in seconds), restart database, perform changes. Then revert the change and restart again.
I had the same issue, a rogue transaction without a end. I restarted the mysqld process. You don't need to truncate a table. You may lose data from that rogue transaction.
Guessing: truncate table bundle_inclusions