Mysql with very high CPU usage

nc12

#1

Hi,

At this moment, mysql is eating almost 300% of my CPU. Looking at the logs, there is no slow query. The general log shows several queries per second, and apparently they are all the same query:

SELECT fileid, storage, path, path_hash, parent, name, mimetype, mimepart, size, mtime, storage_mtime, encrypted, etag, permissions, checksum FROM oc_filecache WHERE storage = ‘30’ AND path_hash = ‘03da3222aedc508d8f137015f25773c9’

Looking at the oc_storages table, I found that 30 refers to
| home::carloslunna | 30 | 1 | NULL |

However, this user has only 2.3MB in its account. Apparently, he is not transfering a high amount of data.

As advised here [Solved] Very high cpu load on mysql after upgrade to nextcloud 10, I turned query_cache_type = on , but it didnt work. Reload php7.0-fpm solves for a while, but after 10 minutes it starts eating all CPU again.

any hints?


Nextcloud version (eg, 10.0.2): 12.0.3.3
Operating system and version (eg, Ubuntu 16.04): Debian Strech (9.2)
Apache or nginx version (eg, Apache 2.4.25): Apache 2
PHP version (eg, 5.6): 7.0
Is this the first time you’ve seen this error?: No

Can you reliably replicate it? (If so, please outline steps): Its happening now; dont know why it started


Remember, this information may be requested if it isn’t supplied; for fastest response please provide as much as you can :heart: Feel free to use a pastebin service, otherwise log files can be indented with 4 spaces on each line to present them in a friendlier way on the forum.


#2

What does happen if you rescan this users files: sudo -u www-data php /path/to/nextcloud/occ files:scan username? Perhaps you can identify a corrupted file by adding -vvv to the occ command and see where it stucks.


#3

Hi Michalng,

We found the file that was causing the problem, and asked the user to delete it.

Still dont know, however, the reason of this behaviour.

thanks,
alan


#4

How did you found that file ?
With the occ -vvv command ?
What kind of file was it ?