[infinispan-dev] L1OnRehash Discussion

Mircea Markus mmarkus at redhat.com
Wed Feb 5 07:44:50 EST 2014


On Feb 4, 2014, at 11:04 AM, Dan Berindei <dan.berindei at gmail.com> wrote:

> On Tue, Feb 4, 2014 at 10:07 AM, Galder Zamarreño <galder at redhat.com> wrote:
> 
> On 28 Jan 2014, at 15:29, William Burns <mudokonman at gmail.com> wrote:
> 
> > Hello everyone,
> >
> > I wanted to discuss what I would say as dubious benefit of L1OnRehash
> > especially compared to the benefits it provide.
> >
> > L1OnRehash is used to retain a value by moving a previously owned
> > value into the L1 when a rehash occurs and this node no longer owns
> > that value  Also any current L1 values are removed when a rehash
> > occurs.  Therefore it can only save a single remote get for only a few
> > keys when a rehash occurs.
> >
> > This by itself is fine however L1OnRehash has many edge cases to
> > guarantee consistency as can be seen from
> > https://issues.jboss.org/browse/ISPN-3838.  This can get quite
> > complicated for a feature that gives marginal performance increases
> > (especially given that this value may never have been read recently -
> > at least normal L1 usage guarantees this).
> >
> > My first suggestion is instead to deprecate the L1OnRehash
> > configuration option and to remove this logic.
> 
> +1
> 
> +1 from me as well

+1

Cheers,
-- 
Mircea Markus
Infinispan lead (www.infinispan.org)







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