Re: [infinispan-dev] Passivation and BCHM WAS: fixing eviction with transactions (critical for Hibernate Search)

On 10 Jun 2011, at 14:18, Sanne Grinovero wrote: > It looks as a good improvement, especially as we remove the locking, > but I still have some doubts: > > 1) as the passivation happens in the eviction thread, is that going to > be fast enough or hindering the eviction performance? especially with > LIRS, being this the user thread it means that put operations suffer a > mayor performance hit (for async caheloaders, see next point). Well > this was the case already, I guess. Yes, this is already the case. > 2) with async stores, the issue is back. The value is not going to be > found while it's "in flight" in the async storage queue; so unless you > want to avoid supporting it for now, the actual removal from the > container should be performed from the async cache loader code. Ugh - yes, I agree.  But I hate the way the mixing of concerns is starting to look.  :-( > So it looks like that - when passivation is enabled - the proper way > to implement this is to use the eviction policy only to identify > what's going to be removed from the container, but not to actually > remove it. > > I'd still focus on having the best performance possible for the case > in which passivation is not enabled, that looks like the "performance > needing" setup, or maybe we need separate eviction strategies fro when > passivation is enabled. Probably true. > 3) so every time we evict an entry, we write it to the store.. I guess > that leads to re-write quite often values which are already in the > store, and for which there's no need to store again. I think this > argument came up before, but we didn't want to track an additional > boolean to keep the memory need low. Still when we're using it as a > cache with eviction rules in place, it seems to me that overall > performance would be better by avoiding more writes at the cost of > being able to store some less entries in memory. With passivation enabled, the entry is only written to the store when removed from memory.  And when activating (store -> memory) it is removed from the store.  So you wouldn't really write twice to the store.

Cheers Manik -- Manik Surtani manik(a)jboss.org twitter.com/maniksurtani Lead, Infinispan http://www.infinispan.org _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev