[Building Sakai] Excessive querying of SAKAI_SITE_PAGE_PROPERTYtable in 2.6?

[Stephen Marquard]

I would say you could probably increase the timeToLive, timeToIdle and
max size to get a better hit rate which would reduce the db traffic.

But it's important to note that these cache entries only get
invalidated from TTLs being expired or the cache being full - they don't
get invalidated by events across the cluster, so if a site page property
is changed on another app server, it will be stale for up to the TTL
value on the others.

But I'm hazy on what it's actually used for, so it may or may not be an
issue.

The only TTL we were concerned about in 2-5-x on the DbFlat caches was
SAKAI_SITE_PROPERTY which is used for some important (to us) things like
Section Info signup status. It may be that more properties are in use in
2-6-x than 2-5-x.

Cheers
Stephen
 
>>> "Maurer, Christopher Wayne" <chmaurer at iupui.edu> 8/27/2009 8:14 PM
>>> 
Here’s what I pulled form one of our app serves:
org.sakaiproject.db.BaseDbFlatStorage.SAKAI_SITE_PAGE_PROPERTY:
count:8715 hits:88589 misses:2700387 hit%:3

Chris


On 8/27/09 2:11 PM, "Stephen Marquard" <stephen.marquard at uct.ac.za>
wrote:

You can increase the TTL and cache properties in sakai.properties,
e.g.

timeToLive at db.cache.SAKAI_SITE_PAGE_PROPERTY=3600
timeToIdle at db.cache.SAKAI_SITE_PAGE_PROPERTY=3600

but looking at our production db, I see hardly anything in that table -
only 7 records with the property "is_home_page".

Cheers
Stephen

>>> Joshua Swink <joshua.swink at gmail.com> 8/27/2009 8:06 PM >>>
I haven't inspected our database, but Sakai says this:

org.sakaiproject.db.BaseDbFlatStorage.SAKAI_SITE_PAGE_PROPERTY:
count:2993 hits:9838 misses:732554 hit%:1

That seems to be a very low hit rate. Would it be helpful to increase
the size of the cache? How can I do that?

Josh

On Thu, Aug 27, 2009 at 11:01 AM, Stephen
Marquard<stephen.marquard at uct.ac.za> wrote:
> There is a cache for that (along with other property lookups) - c/f
SAK-13886
>
> Have a look in Admin Workspace / Memory / Status and see what it says
on one of your app servers, e.g. on a newly started trunk build I see
something like:
>
> org.sakaiproject.db.BaseDbFlatStorage.SAKAI_SITE_PAGE_PROPERTY:
count:40 hits:3 misses:51 hit%:5
>
> Perhaps you have this cache disabled in your config.
>
> Cheers
> Stephen
>
>>>> "Maurer, Christopher Wayne" <chmaurer at iupui.edu> 8/27/2009 7:52 PM
>>>
> Looking at some of our database reports, we see that in the time span
of an hour the following query gets run over a million times:
>
> select NAME, VALUE from SAKAI_SITE_PAGE_PROPERTY where ( PAGE_ID = ?
)
>
> Rumor has it that this is probably for the internationalization of
page/tool titles, is that right?
>
> Are other folks running 2.6.x seeing similar things?  Should we be
concerned about how often this query is being run?
>
> Chris
>
>
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