I have a large database on a Win10 machine, mysqld.exe does a lot of disk I/O, 100%, for hours and hours 100MB/s consistently - mostly writes - persists after numerous reboots. How can I find out what the hell it is actually doing, and stop it? I know the database is not being used at the moment, I want to figure out where this I/O comes from and stop it. The only solutions I found on the internet were general configuration advice, I don't need that, I need to shut this thing down now!
show processlist shows nothing.
UPDATE: The problem was a huge background rollback operation on a table. The solution is:
1) kill mysqld.exe
2) add innodb_force_recovery=3 to my.ini
3) start mysqld.exe
4) export the table (96GB table resulted in about 40GB .sql file)
5) drop the table
6) kill mysqld.exe
7) set innodb_force_recovery=0 to my.ini
8) reboot and import the table back
No idea about data integrity yet, but seems fine.
Thanks to Milney.
If you view the Disk tab of resource monitor from Task Manager you can see which files are being written, this will hint you as to which Database it is;
You can then use something like SELECT * FROM information_schema.innodb_trx\G to view open Transactions and see which statements are causing this
simply Increase InnoDB Buffer Pool Size if default 8MB just increase to 512MB
SET GLOBAL Innodb_buffer_pool_size = 5168709120
Related
im experiencing this NDB CLUSTER Error for a while now.
It started after a cluster shutdown for 2 days due to production shutdown.
Any insights will help. TIA
899 means that the rowid is already allocated.
It is a problem due to the distributed nature of
NDB Cluster. Normally it is a temporary problem
that goes away after a few microseconds.
If it stays then probably some bug have caused the
primary replica and backup replica to be inconsistent.
If that is the scenario the best method to get
back to normal operation is to do the following:
1) Take a backup
2) Perform an initial node restart of one of the data nodes
(presuming that you have 2 data nodes).
The problem should hopefully go away after this.
The backup is simply to ensure that you have the
latest possible backup if something more happens.
i will really appreciate if someone help me with this.
I have spend like 8hours googling around and found no solution to problem.
I have MySQL server version 5.7.7 on Windows server 2008 R2
Table engine is innodb
innodb_file_per_table = 1
I get error "Table is full" when table reaches 4Gb.
MySQL documentation sais that there is actualy only one limit on table size, filesystem.
(http://dev.mysql.com/doc/refman/5.7/en/table-size-limit.html)
HDD where are data stored uses NTFS, just to be sure i created 5Gb file without problems. And sure there is more than 10Gb of free space.
I understand setting "innodb_data_file_path" is irrelevant if "innodb_file_per_table" is enabled, but i tried to set it. No differences.
I have tried to do clean install of mysql. Same result.
EDIT
Guy that installed MySQL server before me accidentally installed 32bit version. Migration to 64bit mysql solved that problem
About the only way for 4GB to be a file limit is if you have a 32-bit version of MySQL. Also check for 32-bit Operating system. (Moved from comment, where it was verified.)
i am also not sure but read this it may help you.
http://jeremy.zawodny.com/blog/archives/000796.html
one more thing one guy had same problem.he had made changes to
NNODB settings for the innodb_log_file_size and innodb_log_buffer_size!changes were :
1) shutdown mysql
2) cd /var/lib/mysql
3) mkdir oldIblog
4) mv ib_logfile* oldIblog
5) edit /etc/my.cnf find the line innodb_log_file_size= and increase it to an appropriate value (he went to 1000MB as he was dealing with a very large dataset... 250million rows in one table). If you are not sure I suggest doubling the number every time you get a table is full error. he set innodb_log_buffer_size to 1/4 of the size of his log file and the problems went away.
I didnt find solution to this, i have no idea why mysql is unable to create more than 4Gb table.
As a workaround i moved only this table back to ibdata by setting "innodb_file_per_table" back to 0 and recreated that table.
Interesting is that even ibdata1 reported table is full when it reached 4Gb, even without setting max and enabled autoexpand.
So i created ibdata2 and let it autoexpand, now i am able to write new data to that table.
I have a problem with my unix server. This started a week ago. One day after a backup (I used to keep 3 backup files) I visited a website on the server but it wouldn't work. I restarted the server and it seemed to be working fine except the mysql service. My attempts to restart it failed. Then I figured that was because the server was full, so I deleted one of the backups, cleaned up some space and the mysql service restarted successfully. Than I figured tables in one of the databases (MYIsam tables) were corrupt. So I repaired them through myisamchk command via ssh and all worked fine. However, the very next day I woke up they were corrupt again (despite mysql was working fine), and this time there was no disk space problem on the server. I repaired them again. The next day the same thing happenned; and this time innodb tables that were part of another database were corrupt as well. I've fixed them too, so now all is working well but I guess the same thing will happen after tonight's backup.
I can't identify the problem and I don't know what logs to look into to understand the problem. Can anyone please help me out? Thanks very much in advance.
No easy answer here. My immediate thought is that the dbase is still busy when the backups commence, possibly corrupting indexes, interferring with caches, etc. Turn on full logging and check for problems when the backup starts happens. Maybe you will find something.
Look for the my.cnf file. On my CentOs it is located in /etc/my.cnf. It will have a config setting for the location of the error log.
My strongest suspect is OOM kill by the kernel or some other issue that results from running the system out of memory. Try this:
Start top on the server and press M to sort by memory so the biggest memory user is at the top.
note the pid of mysqld
manually perform the backup as you observe the value of the RES column in the top output (resident memory size)
once the backup is over see if the pid of mysqld has changed
If the pid has changed (meaning restart took place), and you saw the memory footprint of mysqld take up something comparable to the total amount of system memory, then my suspicion is correct, and we need to lower some settings in my.cnf to make it use less memory, e.g key_buffer_size and innodb_buffer_pool_size.
EDIT - From the log you posted, there are additional issues although it is not clear how they could be contributing to the table corruption. Your server appears to be running with --skip-innodb and your backup script is not able to deal with the absence of InnoDB storage engine printing exception error messages, but nevertheless continuing. It is also attempting to do a repair, which is failing due to the lack of system privileges (error 1 is Operation not permitted). It is possible that encountering those errors triggers some faulty logic in your backup script that leaves the tables corrupted.
At this point I would recommend disabling MySQL backup using the cPanel tool, and using mysqldump or some other solution (e.g. Xtrabackup (https://www.percona.com/doc/percona-xtrabackup/2.3/index.html)) from a cron job instead.
EDIT2 - from the test results. The manual backup does not run the system out of memory and does not crash the server. The jury is still out on the automatic one.
Don't kill mysqld; shut it down gracefully.
Switch from MyISAM to InnoDB; the latter does not suffer from that 'error'.
Currently my database is almost 20 GB big and still growing.
I'm taking a daily backup with mysqldump and it's getting really slow.
So slow that in the meanwhile new connections stack up and eventually cause this error:
SQLSTATE[HY000] [1040] Too many connections
(I could improve the amount of connections that's accepted but that won't do anything because the connections are still just frozen, waiting for the backup to complete, which will lead to timeout)
I've been reading up on some options to improve the speed and this is what I've found:
option --quick (Will probably help)
option --single-transaction (Will prevent tables from being locked, but may cause database to become incorrect)
Master-Slave replication (Probably the best thing I could do, one problem, I have only one server available)
The master-slave replication really sounds like it's the best option since I can stop the slave from updating, take the backup, and let it resume syncing. The problem is I only have one fysical machine to work with.
I know that I can set up multiple mysql instances on this one server. The question is: Is it wise to do so?
The slave is really only used to generate that backup file (which will be copied to a different disk on the network) so that the master can stay live.
if you use just innodb - try xtrabackup.
if you use both myisam and innodb - flush + lvm snapshot + file-level copy might work for you.
indeed replication slave for backups is good idea as well. just remember to periodically check data consistency between the master and the slave.
I am working on a project where i need to create a database with 300 tables for each user who wants to see the demo application. it was working fine but today when i was testing with a new user to see a demo it showed me this error message
1030 Got error 28 from storage engine
After spending some time googling i found it is an error that is related to space of database or temporary files. I tried to fix it but i failed. now i am not even able to start mysql. How can i fix this and i would also like to increase the size to maximum so that i won't face the same issue again and again.
Mysql error "28 from storage engine" - means "not enough disk space".
To show disc space use command below.
myServer# df -h
Results must be like this.
Filesystem Size Used Avail Capacity Mounted on
/dev/vdisk 13G 13G 46M 100% /
devfs 1.0k 1.0k 0B 100% /dev
To expand on this (even though it is an older question); It is not not about the MySQL space itself probably, but about space in general, assuming for tmp files or something like that.
My mysql data dir was not full, the / (root) partition was
I had the same issue in AWS RDS. It was due to the Freeable Space (Hard Drive Storage Space) was Full. You need to increase your space, or remove some data.
My /tmp was %100. After removing all files and restarting mysql everything worked fine.
My /var/log/apache2 folder was 35g and some logs in /var/log totaled to be the other 5g of my 40g hard drive. I cleared out all the *.gz logs and after making sure the other logs werent going to do bad things if I messed with them, i just cleared them too.
echo "clear" > access.log
etc.
Check your /backup to see if you can delete an older not needed backup.
I had a similar issue, because of my replication binary logs.
If this is the case, just create a cronjob to run this query every day:
PURGE BINARY LOGS BEFORE DATE_SUB( NOW(), INTERVAL 2 DAY );
This will remove all binary logs older than 2 days.
I found this solution here.
A simple:
$sth->finish();
Would probably save you from worrying about this. Mysql uses the system's tmp space instead of it's own space.
sudo su
cd /var/log/mysql
and lastly type: > mysql-slow.log
This worked for me
Drop the problem database, then reboot mysql service (sudo service mysql restart, for example).
If you want to use the tokudb plugin
This can happen if you have less than 5% (by default) of free space.
see the option: tokudb_fs_reserve_percent