[Building Sakai] Read Committed

[Ethan Kromhout]

Thank you Sam! We are running Sakai 2.9.2 on MySQL 5.5.12 Enterprise. 
What happens is that we are running along fine, not much going to the 
slow query log but the occasional forum or grade query. Then we'll 
rather suddenly go to a bad state where lots of queries that normally 
run well are running slowly, and application performance slows to a 
crawl. This happens at high load times, though not every time we are 
busy. This is the first week of classes, and this occurred twice on 
Tuesday and once  on Thursday, but we ran fine for 48 hours in between.

We have only been able to get out of the state by shutting users out, at 
which point we have making changes we hope will improve performance and 
restarting. Changes so far include increasing 
innodb_buffer_pool_instances to 8, increasing innodb_buffer_pool_size to 
24G, increasing innodb_thread_concurrency to 24, increasing 
innodb_log_file_size to 512M, and increasing innodb_log_files_in_group to 4.

Thanks again,

Ethan

On 8/22/14 5:16 PM, Sam Ottenhoff wrote:
> I believe this is the recommended value for MySQL:
>
>
> defaultTransactionIsolationString at javax.sql.BaseDataSource=TRANSACTION_READ_COMMITTED
>
> What kind of performance issues are you running into?  What version of
> MySQL?  Any specific slow queries or operations?
>
>
> On Fri, Aug 22, 2014 at 4:51 PM, Ethan Kromhout <ethan_kromhout at unc.edu
> <mailto:ethan_kromhout at unc.edu>> wrote:
>
>     We have been dealing with some performance issues in our MySQL instance
>     for Sakai, and have been reading about the possibility of setting our
>     isolation level to READ COMMITTED. A comment I found in a Jira noted
>     that your binlog-format needed to be row for replication, but I didn't
>     find much other comment about this change.
>
>     I was hoping to hear from others as to the safety and benefits of using
>     READ COMMITTED for Sakai.
>
>     Thanks,
>
>     Ethan
>
>     _______________________________________________
>     sakai-dev mailing list
>     sakai-dev at collab.sakaiproject.org
>     <mailto:sakai-dev at collab.sakaiproject.org>
>     http://collab.sakaiproject.org/mailman/listinfo/sakai-dev
>
>     TO UNSUBSCRIBE: send email to
>     sakai-dev-unsubscribe at collab.sakaiproject.org
>     <mailto:sakai-dev-unsubscribe at collab.sakaiproject.org> with a
>     subject of "unsubscribe"
>
>