I'am using nodeJs createpool to connect to database and pool.query to execute a sql statement.
Sometime My data base server is taking a lot of time to execute queries.
It shows deadlock and sleep queries 'waiting for handler commit'. After killing those sleep query deadlocks gets resolved everything start running smooth what might be the reason behind this please help me guy.
I'am sharing the screen shot of process list below.
I tried using start transaction; commit;
Tried using routines procedures,
Related
If I run a SQL query in MySQL workbench and the connections time out after 30 seconds because it is taking a long time. Does my Query continue executing on the MySQL server even though I am disconnected?
For example, if I am doing an update and the update loops over a billion records. Does the MySQL server disconnect me first then it finishes the query after? Or does it disconnect me and terminate the query?
It does. As Mustafa mentioned, you can see the query still running if you look at "Administration tab" --> Management --> Client Connections.
Also good to remember that you can change the 30sec cap to longer, shorter or none.
Yes, MySQL Workbench can disconnect and the query keeps running. This has been reported as a bug, but it's in the "Verified" state, which means it is not fixed: https://bugs.mysql.com/bug.php?id=78809
See also this related SO thread: MySQL Query running even after losing connection
If you have a long-running query that needs to do a bulk update, you may need to change the MySQL Session timeout options in the MySQL Workbench preferences. Alternatively, don't use MySQL Workbench for long-running jobs, use the mysql command line tool.
I have a MySQL database with multiple tables. When I run a simple SELECT command on one of the tables, it gives the "lost connection" error, but when I run the same command on any of the other tables, it works just fine. Does anyone know what could be the cause of this issue? I'm running the commands from the MySQL Workbench.
You must set the 'Interactive_timeout' and 'wait_timeout' properties in the mysql configuration file to the values you need.
Quite likely there is some sort of a transaction running. Whether you started the transaction via a sql command (i.e. START TRANSACTION) or whether some other query (possibly from a GUI) started a transaction (Like an ALTER TABLE command when adding a column) and the transaction never finished.
Run the command
SHOW FULL PROCESSLIST;
to find the IDs of all processes that are running for your user
You can then kill the processes by running the command
KILL <PROCESS ID> (i.e. KILL 40196;)
When you find and stop the process that contained the transaction that never finished you will likely be able to query the table again. Your table will be queryable again, and you can look further into solving the problem of why the transaction was started but never finished.
I am beginner to MySQL and SQL and I am learning these technologies from MySQL and MyISAM websites.
I am learning the KILL command now and have learned how to use KILL CONNECTION. But when I come to learn KILL QUERY from MySQL and MyISAM websites where they simply provided information about KILL QUERY that they terminate query that the specified connection id is executing.
Other user (not me) executes INSERT and DELETE queries but when i have used KILL QUERY by getting the connection id of other user via SHOW PROCESSLIST command, it says
Query OK, 0 rows affected (0.01 sec)
But nothing happen to other user.
I just want to know that what is the exact use of this command. What is the purpose of this KILL QUERY command. Can anyone tell me?
Some useful pointers:
How can I stop a running MySQL query?
MySQL Kill query
How to kill all processes for a Specific user
MySQL Manaul - Kill
You need to have some clarity here KILL will kill the connection, but KILL QUERY will only kill that query and will leave that connection intact.
Really, if you are using KILL QUERY on another users command, this can only really be noticable if their query is running for longer than your Kill Query command, so if it's a slow query, because [most] queries will execute and close within a fraction of a second, so by the time you've KILLed the other users query, their query may well have completed and closed anyway.
I suspect this is what you are seeing, that you're trying to kill a query that closes and is finished before the kill command can execute.
Killing queries seems (from literature) only useful for slow and long running queries, and why this is so should be obvious from the above.
Edit:
(I had this ready to post on my original answer and then took it out as being irrelevant, but seems to be more relevant now due to comments!)
From the MySQL Manual:
Note
You cannot use KILL with the Embedded MySQL Server library because the embedded server merely runs inside the threads of the host application. It does not create any connection threads of its own.
So to answer your question in the comment, I think that you may be running MySQL embedded so your kill calls will not function.
I'm new to MySQL database and got some issue with table lock/deadlock. We are running a system with a heavy transactions run everyday and sometime deadlock happened. I would like to know what happened to the transactions if they exceeded wait timeout. Are they canceled (roll-back) ? Do we need to manually run the transaction again or did application auto retry the transaction after deadlock is resolved?
I'm using MySQL 5.7 with Innodb engine.
Thanks
it dosen't matter what db you are using ,if you are using a transaction it will only be committed on success ie if u look closely there is a commit transaction command at the end of try which u write , unless that line is invoked No changes to the DB will be made hence you can be assured that it will be roll backed at the situation of timeout error
I am running a very long procedure from MySQL workbench 6.1 and it has been running for quite a while now (so I can't just drop it and restart it later) and from my calculations it will probably run for a long while more.
I set the "connection drop" variable to a very big time, however I will have to turn off the computer before the end of that (so I can't just wait for it to time out).
The procedure doesn't return anything, so I don't really care about not receiving its result.
Is there a way to close workbench without having to stop the procedure from running?
Thanks a lot!
Simply said: no, it's not possible.
The running query is bound to a specific context: the connection from the client to server, which includes certain states (e.g. transaction, sql mode and others). Killing the client means to kill the connection. This will ultimatively kill any processing the server is doing for this client connection.