[GEODE-5666] Can't use java enums inside a cache key

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Information Provided
• Component/s: client/server, docs, general, serialization
• Assignee: Karen Smoler Miller
• Reporter: Naoufal
• Created: 30/Aug/18 15:09
• Updated: 10/Oct/18 17:56
• Resolved: 10/Oct/18 17:56

Description

Use case:

• Partitioned region with one shard
• I put data which key contains an enum.
• Sometimes the data is not returned when we ask for that key. Although it's not caught in the client, this exception is raised :

PartitionedRegionException( "Object hashCode inconsistent between cache peers. Here ...)

I Believe it's related to the limitation of using raw java enum in the hashcode generation. When a server checks hashcode consistency with its peers, it will fail for those keys, since the enum hashcode is equal to Object.Identity a.k.a: its address in the JVM. For this reason the hascode will differ between two peers.

You maybe aware of this limitation.

• If so it should be properly mentioned in the documentation, possibly with example and workaround (like using the enum's ordinal()). I could not find it any such thing.

• Otherwise, is it something that could be handled better? For example by sending the whole keys instead of hashes?

Regards,
Naoufal

Issue Links

• relates to: GEODE-5845 Document that an enum should never be used for keys