[infinispan-dev] Issue with cache blocks for local read-only cache

[Galder Zamarreño]

This is code written in JBoss Cache days to deal with situations where putFromLoad might try to store stale data (if data is deleted in between a database read and putFromLoad being called).

Indeed this can happen with read only data, and has nothing to do with clustering.

The original issue is: https://hibernate.onjira.com/browse/HHH-3817

I'll check how this can be improved.

Cheers,

On Sep 18, 2012, at 4:55 PM, Sanne Grinovero <sanne at infinispan.org> wrote:

> There seems to be a single (global) reentrant lock which is acquired
> on any put; I don't know much about the module design, but there is a
> comment close to the lock acquisition mentioning a need to flush an
> operations queue to avoid a deadlock.
> Could it just make sure to reorder keys, so that deadlocks are avoided?
> 
> On 18 September 2012 16:26, Manik Surtani <manik at jboss.org> wrote:
>> Agreed.
>> 
>> This locking appears to be in the 2LC integration code to guard a local
>> collection though - there must be better, non-blocking ways to guard this -
>> if it is needed at all for RO entities.
>> 
>> - M
>> 
>> On 18 Sep 2012, at 15:18, Andrig Miller <anmiller at redhat.com> wrote:
>> 
>> What I find interesting, is that in this use case, READ_ONLY concurrency
>> strategy and a local cache (no invalidation and no replication), there is no
>> need to do any locking.
>> 
>> If we can get to a solution without any locking that would be ideal.
>> 
>> Andy
>> 
>> ________________________________
>> 
>> From: "Manik Surtani" <manik at jboss.org>
>> To: "Ståle W. Pedersen" <spederse at redhat.com>
>> Cc: "Galder Zamarreño" <galder at redhat.com>, "John O'Hara"
>> <johara at redhat.com>, "Jeremy Whiting" <jwhiting at redhat.com>, "Andrig Miller"
>> <anmiller at redhat.com>, "Steve Ebersole" <steve at hibernate.org>,
>> "infinispan-dev" <infinispan-dev at lists.jboss.org>
>> Sent: Tuesday, September 18, 2012 8:13:43 AM
>> Subject: Re: Issue with cache blocks for local read-only cache
>> 
>> 
>> Looking at your profiler snapshot, these locks are in the Hibernate 2nd
>> level cache implementation for Infinispan.  Galder, any ideas?
>> 
>> - M
>> 
>> On 18 Sep 2012, at 13:43, Ståle W. Pedersen <spederse at redhat.com> wrote:
>> 
>> hi galder and manik, sorry for sending this mail to so many, but we've ran
>> into a issue that prevents us from further scaling of the
>> specjenterprise2010 benchmark.
>> 
>> so when doing specjenterprise2010 benchmark testing we've seen a lot of
>> blocks caused by the entity/query cache. we've been testing with only
>> caching a simple entity bean that's read-only and queries related to this
>> entity (selects).
>> 
>> here is a screenshot of the hotspot
>> found:https://dl.dropbox.com/u/30971563/specjent_block.png
>> 
>> here is the standalone.xml:
>> https://dl.dropbox.com/u/30971563/standalone-full.xml
>> 
>> here is the orm.xml: https://dl.dropbox.com/u/30971563/order_orm.xml
>> 
>> what we don't understand is why there are so many puts into the cache for an
>> object that is marked as read-only. when we're testing without caching we do
>> not see any blocks.
>> 
>> any help/ideas would be great. if anyone want a jprofiler snapshot of the
>> run, let me know.
>> 
>> regards, ståle
>> --
>> JBoss Performance Team Lead
>> JBoss by Red Hat
>> 
>> 
>> --
>> Manik Surtani
>> manik at jboss.org
>> twitter.com/maniksurtani
>> 
>> Platform Architect, JBoss Data Grid
>> http://red.ht/data-grid
>> 
>> 
>> --
>> Manik Surtani
>> manik at jboss.org
>> twitter.com/maniksurtani
>> 
>> Platform Architect, JBoss Data Grid
>> http://red.ht/data-grid
>> 
>> 
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> 
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--
Galder Zamarreño
galder at redhat.com
twitter.com/galderz

Project Lead, Escalante
http://escalante.io

Engineer, Infinispan
http://infinispan.org