[sakai2-tcc] KNL-652 site caching testing (UMich preliminary testing)

[May, Megan Marie]

Isn't this already on the blocker list for 2.8 or are you proposing an elevation of the bug?

Megan

-----Original Message-----
From: sakai2-tcc-bounces at collab.sakaiproject.org [mailto:sakai2-tcc-bounces at collab.sakaiproject.org] On Behalf Of Aaron Zeckoski
Sent: Friday, March 11, 2011 8:55 AM
To: Anthony Whyte
Cc: sakai2-tcc Committee
Subject: Re: [sakai2-tcc] KNL-652 site caching testing (UMich preliminary testing)

I think that is a really good plan.
It may be worth backporting to 2.7 as well.
-AZ


On Fri, Mar 11, 2011 at 8:38 AM, Anthony Whyte <arwhyte at umich.edu> wrote:
> I recommend that if Michigan's production testing continues to proves 
> positive we should include this fix in sakai-2.8.0, even if it means 
> we delay the release a further 7-10 days in order to work it in.
> Cheers,
> Anthony
>
> Begin forwarded message:
>
> From: "David Haines (JIRA)" <bugs-admin at sakaiproject.org>
> Date: March 11, 2011 3:25:42 PM GMT+02:00
> To: mt-jira at collab.sakaiproject.org
> Subject: [mt-jira] [Sakai Jira] Commented: (KNL-652) SIte caching is 
> broken in Kernel 1.1.9
>
>
>    [
> https://jira.sakaiproject.org/browse/KNL-652?page=com.atlassian.jira.p
> lugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=122629#c
> omment-122629
> ]
>
> David Haines commented on KNL-652:
> ----------------------------------
>
> Load testing at Michigan using a lightly patched 1.1.9 kernel 
> indicates that the memory leak is significantly reduced.  This 
> required applying 4 patches related to caching: KNL-293, KNL-654, 
> KNL-662, and KNL-664 to fix multiple leaks.  Our tests indicate that a 
> site cache size of 10000 gives a site cache hit rate of around 90%.  
> We should have a week or more of production experience with these 
> changes, applied to a 1.1.10 kernel, as of the week of 4/4/11.
>
> SIte caching is broken in Kernel 1.1.9
>
> --------------------------------------
>
>                Key: KNL-652
>
>                URL: https://jira.sakaiproject.org/browse/KNL-652
>
>            Project: Kernel - K1
>
>         Issue Type: Bug
>
>         Components: Impl
>
>   Affects Versions: 1.1.9
>
>           Reporter: David Haines
>
>           Assignee: David Horwitz
>
>           Priority: Blocker
>
>            Fix For: 1.3.0
>
>        Attachments: Classes in Heap.png, Top Consumers.png
>
>
> Site caching is broken in the K1 kernel 1.1.9 release.  Sites objects 
> themselves are cached but when sites are evicted from the site cache 
> the secondary, in memory, caches for tools, pages, and groups are not 
> cleaned up, the references to the objects remain and those objects can 
> not be garbage collected.  Over time this leads to large numbers of 
> objects that won't be used but will consume memory.  At Michigan, 
> after not restarting Sakai for a couple of weeks we ended up with 
> almost 2GB of memory devoted to the site cache.  That caused long 
> periods of fruitless garbage collection and a degradation of service.
>
> The problem is avoided in the short run by restarting Sakai instances 
> or by manually clearing the caches with the Admin memory tool.
>
> A patch to address this is being tested at Michigan.
>
> Note that the only way to control Ehcache cache memory consumption for 
> a memory only cache is to limit the number of elements in the cache.  
> KNL-293 should also be applied when the site caching is fixed so that 
> there is a way to adjust the site cache size to match local requirements.
>
> --
> This message is automatically generated by JIRA.
> -
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> http://www.atlassian.com/software/jira
>
>
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--
Aaron Zeckoski - Software Engineer - http://tinyurl.com/azprofile _______________________________________________
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