[infinispan-dev] TreeCache needs Flag(s) to be maintained for the duration of a batch/tx

[Galder Zamarreño]

On Jan 4, 2011, at 5:48 PM, Manik Surtani wrote:

> 
> On 23 Dec 2010, at 16:48, Galder Zamarreño wrote:
> 
>> Hi,
>> 
>> Re: https://issues.jboss.org/browse/ISPN-841
>> 
>> The issue here is the fact that if you call a TreeCache operation passing flags, you want this flags to apply to all cache operations encompassing the tree cache op. Now, the thing to remember about flags is that they get cleared after each cache invocation, so we must somehow pass flags around to all methods that operate on the cache as a result of a treecache.put for example.
>> 
>> A rudimentary way to do so would be to pass Flag... to all methods involved which is not pretty and hard to maintain. An alternative would be to have some flags thread local that gets populated on start of tree cache operation and gets cleared in the end of the operation. Although this might work, isn't this very similar to what CacheDelegate does to maintain flags except that instead of keeping them for a cache invocation, it would keep them hanging around until the end of the operation? TreeCache operations are bounded by start/stop atomic calls that are essentially calls to start/stop batches. So, it seems to me that what this is asking for is for a wider functionality to keep flags for the duration of a transaction/batch, which would most likely be solved better in core/
> 
> Hmm; flags are explicitly designed for per-invocation application.  If we change this to apply to an entire transaction in core (e.g., by storing the flags in a transaction context rather than an invocation context) it will break a lot of existing code.

I was not advocating for changing the meaning of flags, but rather adding to it. IOW, have the ability to set flags on a per invocation basis is definitely needed, but maybe core could also benefit from having the ability to set a flag for a tx, so have the two options available somehow. I'm just saying this out loud in case there's any other such use cases elsewhere apart from tree cache.

> 
> I think it cannot/should not be solved in core but rather in the TreeCache.  A thread local makes sense.

Ok. If some other component needs a similar thing, we'd then think about it again.

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

--
Galder Zamarreño
Sr. Software Engineer
Infinispan, JBoss Cache