[MDEV-11565] possible bug? #innodb-encryption-threads Created: 2016-12-14  Updated: 2016-12-29  Resolved: 2016-12-29

Status: Closed
Project: MariaDB Server
Component/s: Configuration
Affects Version/s: 10.1.19
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: none now Assignee: Jan Lindström (Inactive)
Resolution: Not a Bug Votes: 0
Labels: need_feedback
Environment:

Centos 7.x


 Description   

hi team

I'm having a peculiar situation, a problem here with my config, which config is pretty galera-vanilla.
Namely, if I set these:

plugin-load-add = file_key_management.so
 
file-key-management
 
file-key-management-filename = /var/lib/mysql/.keys.txt
 
innodb_file_per_table = 1
 
innodb-encrypt-log
 
innodb-encryption-threads = 4     <= # this ! one here

I get constant load on four cores, it would fluctuate just under %400 CPU (24*7). I'd assume that innodb-encryption-threads value causes it, and whatever the value might be it will be reflected in CPU usage.
I wonder if you too see it.
I my case I think it does something more to one system, it crashes the bloody thing to the extent where cold reboot is needed.

MariaDB-client-10.1.19-1.el7.centos.x86_64
 
MariaDB-shared-10.1.19-1.el7.centos.x86_64
 
MariaDB-common-10.1.19-1.el7.centos.x86_64
 
MariaDB-server-10.1.19-1.el7.centos.x86_64

best,
L



 Comments   
Comment by Elena Stepanova [ 2016-12-17 ]

I am not getting this, but we've had similar complaints before, so I'm sure it can happen. There is some explanation in MDEV-11581, please take a look, maybe it will help.

Comment by Jan Lindström (Inactive) [ 2016-12-29 ]

Naturally, if you set up innodb-encryption-threads = 4, these threads will periodically check all tablespaces if they need (1) key rotation, (2) transform tablespace from unencrypted to encrypted, (3) transform tablespace from encrypted to unencrypted and (4) for scrubbing (physically zero delete marked rows). If you do not want or need any of this you may very well set innodb-encryption-threads = 0 and all old and new tables you need to encrypt will be encrypted if create table contains ENCRYPTED=yes. If you use ENCRYPTED=default or do not provide ENCRYPTED option but still expect you tables to be encrypted you need to set these threads.

Comment by Jan Lindström (Inactive) [ 2016-12-29 ]

Works as designed, consider used configuration and if needed correct the number of background encryption threads.

Comment by none now [ 2016-12-29 ]

but the thing which makes it peculiar in my case and which made me report it here is - it happens to mariadb with databases where there is nothing going on, nothing is happening. No activities, no queries, but that constant %400 cpu load remains. Is this still normal, expected?
regards

Comment by Jan Lindström (Inactive) [ 2016-12-29 ]

Yes normal, expected. Those threads will do their work (i.e. check every tablespace) even if nothing else is done.

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