[Building Sakai] Severe DB Performance Issues for 2.9

[Sam Ottenhoff]

It's the right format, but it's one of about 50 caches that every Sakai
instance should have........ Admin Workspace -> Memory -> Status.


On Wed, Sep 4, 2013 at 12:11 PM, Sobieralski, Damian Michael <
dsobiera at indiana.edu> wrote:

>  Is this the right stat?****
>
> ** **
>
> HardCache: count:10000 hits:42596 misses:11992 hit%:78****
>
> ** **
>
> ** **
>
> *From:* Sam Ottenhoff [mailto:ottenhoff at longsight.com]
> *Sent:* Wednesday, September 04, 2013 11:56 AM
> *To:* Sobieralski, Damian Michael
> *Cc:* sakai-dev at collab.sakaiproject.org
> *Subject:* Re: [Building Sakai] Severe DB Performance Issues for 2.9****
>
> ** **
>
> If you're not running 2.9.2+ web tool, then SAK-23841 is not relevant.****
>
> ** **
>
> Can you share your cache hit/missed stats from the Admin Workspace ->
> Memory tool?****
>
> ** **
>
> On Wed, Sep 4, 2013 at 11:36 AM, Sobieralski, Damian Michael <
> dsobiera at indiana.edu> wrote:****
>
> IU is into the 2nd week of classes and yesterday we saw heavy CPU load on
> database which then backed up the app servers.   Our users experienced
> System latency which then resulted in a lot of errors and very frustrated
> users.     As traffic slowed, the system recovered.
>
> We're running a base 2.9.0 with cherry picked enhancements and performance
> fixes.  We did apply KNL-1011.
>
> What we are noticing is under average to high load the DB is running at
> 100%.  We are noticing a LOT of calls such as:
>
> SELECT TOOL_ID,
>    REGISTRATION,
>    TITLE,
>    LAYOUT_HINTS,
>    PAGE_ORDER
> FROM SAKAI_SITE_TOOL
> WHERE PAGE_ID = :1
> ORDER BY PAGE_ORDER ASC
>
> And
>
> SELECT NAME,
>    VALUE
> FROM SAKAI_SITE_PAGE_PROPERTY
> WHERE ( PAGE_ID = :1 )
>
> Pre 2.9 upgrade we only had one query that ran over a million times. Both
> of these had over 140 million executions.
>
> Any ideas what might be causing this behavior?  And, more importantly,
> what can be done to reduce this? This is a SEVERE problem for us as
> yesterday our system basically grinded to a halt w/ the DB locked at 100%.
>
> We did find this: https://jira.sakaiproject.org/browse/SAK-23841
>
> But as far as I know we're not using XFrame.  But could this still be the
> issue?
>
> Thanks.
>
> ---
> Damian Sobieralski
> Indiana University
>
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