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Date: Wed, 13 Jul 2011 18:58:14 +0100
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Subject: Re: Connection Pooling
From: Sean Owen <srowen@gmail.com>
To: user@mahout.apache.org
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Yes it reloads after a configurable interval, or on demand.

Clearing the cache for a user ID only means that user's data is recomputed.
It's not bad to call this frequently per se... I suppose you want to let it
cache as much and for as long as is valid and acceptable to your app.

Your bottleneck is no longer reading from the DB if you're having it load
into memory.

On Wed, Jul 13, 2011 at 6:19 PM, Salil Apte <salil@offlinelabs.com> wrote:

> Awesome, I will give ReloadFromJDBCDataModel a try. How does this
> particular data model update itself on database changes? Does it just
> happen periodically and if so, can this rate be change easily?
>
> Lastly, will calling clear(userId) on a recommender frequently be bad
> for performance? I'm assuming with such small data amounts that the
> actual recommendation algorithm is quite speedy and that the DB is
> really the big bottleneck?
>
> On Wed, Jul 13, 2011 at 2:11 AM, Sean Owen <srowen@gmail.com> wrote:
> > That's all correct, it reads a lot. But you can avoid a lot of it by
> using
> > caching wrappers.
> > You also don't need to dump to a file. Use ReloadFromJDBCDataModel.
> >
> > On Wed, Jul 13, 2011 at 9:57 AM, Vitali Mogilevsky
> > <vitali@playedonline.com>wrote:
> >
> >> Hey,
> >> I got the same problem, of slowness while using MYSQL data model, after
> a
> >> small research and looking into mysql's query log, revealed that user -
> >> user
> >> recommendation just floods the database with thousands and thousands of
> >> requests.
> >> and thats on small database.
> >> for now Im dumbping the database into file, and using filedata model
> which
> >> works much faster
> >>
> >>
> >
>

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