CODEWITHSUNDEEP
jboss7.xinfinispan
Phillip Atkinson
Phillip Atkinson

Reputation: 199

Infinispan seems to be having phantom or dirty reads

I'm using JBoss EAP 6.0.1.GA (AS 7.1.3.Final) and the bundled Infinispan 'Brahma' 5.1.8.Final. I've configured Infinispan to be use a replicated, synchronous cache with isolation level = SERIALIZABLE and enabled batching on the cache.

Sample code I'm running:

Cache<String, List> cache = cacheContainer.getCache();
cache.startBatch();
List data = cache.get(key);
data.add(some value);
cache.put(key, data);
cache.endBatch(true);

edit Try as I might, if 2 nodes call this same block at the same time, every so often the data list only contains data from one node. It looks like it's a "* read" problem of various isolation levels, which I thought I guaranteed wouldn't happen by setting the isolation level to Serializable. /edit

I've also tried using an AdvancedCache, where my code would first do this to try to get the transaction lock as early as possible:

// javadocs on this flag seem to indicate this is a good idea if doing a get-update-put
Cache<String, List> cache = cacheContainer.getCache();
AdvancedCache<String, List> advancedCache =
            cache.getAdvancedCache().withFlags(Flag.FORCE_WRITE_LOCK);

I've also played around with setting the transaction mode (NON_XA / Pessimistic), but I don't think that matters if I'm not actually using big-T Transactions (because of using batching instead)? And changing transaction modes I still see the above scenario occasionally).

Is there some code or configuration I'm missing or that is incorrect here?

Upvotes: 1

Views: 290

Answers (2)

Phillip Atkinson
Phillip Atkinson

Reputation: 199

The answer was that version 5.x of Infinispan apparently had a bug where it wasn't acquiring a remote lock when 

cache.getAdvancedCache().withFlags(Flag.FORCE_WRITE_LOCK)

was called. See https://issues.jboss.org/browse/ISPN-3266

I upgraded to 6.0.2Final and it seems to work now with no phantom/dirty reads.

(thanks to Wiliam at the JBoss community forums for his answer and help! https://community.jboss.org/message/884303)

Upvotes: 0

Dan Berindei
Dan Berindei

Reputation: 7204

Infinispan doesn't actually support the SERIALIZABLE isolation level, instead it downgrades to REPEATABLE_READ.

But I think the problem with your test is that Infinispan doesn't do defensive copies of the objects it stores - the assumption is that you will do the copy yourself and store the copy in the cache. So when you call data.add(some value), you modify the actual cache value and not a local copy.

You can change that behaviour by enabling storeAsBinary.storeValuesAsBinary in the cache configuration.

Upvotes: 1

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