[infinispan-dev] SingleJoinTest#testTransactional failure

[Manik Surtani]

On 1 Dec 2010, at 01:17, Mircea Markus wrote:

> 
> On 30 Nov 2010, at 17:25, Manik Surtani wrote:
> 
>> 
>> On 30 Nov 2010, at 17:08, Mircea Markus wrote:
>> 
>>> 
>>> On 30 Nov 2010, at 17:03, Manik Surtani wrote:
>>> 
>>>> 
>>>> On 30 Nov 2010, at 16:51, Mircea Markus wrote:
>>>> 
>>>>> 
>>>>> On 30 Nov 2010, at 16:42, Vladimir Blagojevic wrote:
>>>>> 
>>>>>> On 10-11-30 1:35 PM, Mircea Markus wrote:
>>>>>>> On 30 Nov 2010, at 14:30, Vladimir Blagojevic wrote:
>>>>>>> 
>>>>>>>> On 10-11-30 10:49 AM, Vladimir Blagojevic wrote:
>>>>>>>>> I like your solution. It seems to be less disruptive to ongoing
>>>>>>>>> transactions then the other two solutions.
>>>>>>>>> 
>>>>>>>>> How would you safely detect that K is locked by another tx and thus skip
>>>>>>>>> locking?
>>>>>>>> I do *not* think I can do the following in LockingInterceptor:
>>>>>>>> 
>>>>>>>> public Object visitInvalidateCommand(InvocationContext ctx, InvalidateCommand command) throws Throwable {
>>>>>>>> try {
>>>>>>>>   if (command.getKeys() != null) {
>>>>>>>>      for (Object key : command.getKeys()) {
>>>>>>>>         if(!lockManager.isLocked(key))
>>>>>>>>             entryFactory.wrapEntryForWriting(ctx, key, false, true, false, false, false);
>>>>>>>>      }
>>>>>>>>   }
>>>>>>>>   return invokeNextInterceptor(ctx, command);
>>>>>>> Perhaps you only want to run invokeNext for the keys for which you acquired locks?
>>>>>> 
>>>>>> I would love to but I do not see a method wrapEntryforWritingIfYouCan :-) What do you do in these kinds of situations? Set timeout to 10 msec and catch TimeoutException?
>>>>> My point is you don't want to invalidate(invoke next) keys for which you don't have the locks. These would be invalidated(i.e. removed) at commit time.
>>>> 
>>>> Right, provided the tx knows to invalidate these keys at commit (or rollback).  Right?
>>> At commit/rollback, the tx can iterate over they keys involved (ones brought here by prepare): if the key is no longer mapped to this node then simply remove it; otherwise apply the change. 
>> 
>> Not unless L1 is enabled and you *want* the entry in L1 there.
> even if the entry is removed from L1 this is not incorrect (at most sub-optimal).

Of course, but you can't expect *every* transaction to *always* remove entries it touches from L1.  This completely defeats the purpose of L1.

The transaction needs to be made aware that some of the keys it touched has been exposed to rehashing and hence should be removed from L1 when the tx completes.  I don't think this is hard to do: what we'd need is:

* A subclass of the TxInvocationContext (DistributedTxInvocationContext?) which maintains a set of keys potentially rehashed
* An L1InvalidationCommand would try and invalidate a key.  If it is unable to lock this key _and_ the lock is held by a transaction, add the key to the given transaction's context's potentially rehashed key set
* When the transaction completes, it invalidates any keys before releasing locks.

WDYT?

--
Manik Surtani
manik at jboss.org
Lead, Infinispan
Lead, JBoss Cache
http://www.infinispan.org
http://www.jbosscache.org