Entry processor issue

[Joan Balagueró]

Hello,

hazelcast 4.2.6.

I have a map using an entry processor. Every time an element is found on the cache we increment an integer field by calling the 'addHit()' method that calls the entry processor:

public void addHit(String key) {
  this.mapRecache.executeOnKey(key,  this::applyHitToKey);
}

// This is the entry processor

private boolean applyHitToKey(Map.Entry<String, HitInfo> entry) {
  entry.setValue(entry.getValue().addHit());
  return true;
}

The point is after increment this value, the expiration time and TTL fields are changed:

These are the values before/after executing the entry processor:

(BEFORE)

addHit :: EntryView{key=36|null|1|null|null|2023-01-21|2023-01-25|9.1|10.<null>|11.0|13.AO-B0<_>AO-B1|, value=com.ventusproxy.proxy.cache.reglas.recache.HitInfo@427d2fe, cost=1198, creationTime=1675077655000, expirationTime=1675077675000, hits=0, lastAccessTime=0, lastStoredTime=0, lastUpdateTime=1675077655000, version=0, ttl=20000, maxIdle=9223372036854775807}

(AFTER)
addHit :: EntryView{key=36|null|1|null|null|2023-01-21|2023-01-25|9.1|10.<null>|11.0|13.AO-B0<_>AO-B1|, value=com.ventusproxy.proxy.cache.reglas.recache.HitInfo@427e946, cost=1198, creationTime=1675077655000, expirationTime=9223372036854775807, hits=1, lastAccessTime=1675077660000, lastStoredTime=0, lastUpdateTime=1675077660000, version=1, ttl=9223372036854775807, maxIdle=9223372036854775807}

The consequence is that entries never expire.

Is this a bug or I'm doing something wrong?

Thanks,

Joan.

[Joan Balagueró]

I have seen this issue that seems related to this:

https://github.com/hazelcast/hazelcast/issues/16987

we have tried this:

public class AddHitEntryProcessor implements EntryProcessor<String, HitInfo, Object>, Offloadable {

 @Override  
 public Object process(Map.Entry<String, HitInfo> entry) { 
   entry.setValue(entry.getValue().addHit());
   return null;
 }

 @Override  
 public EntryProcessor<String, HitInfo, Object> getBackupProcessor() {
    return null;
 }

 @Override
 public String getExecutorName() {
   return Cluster.DEFAULT_ES_NAME;
 }
}

Implementing or not implementing the offloadable interface does not make any difference, the TTL and thus the expiration date are updated.

Any help on this? This is blocking us.

Thanks.

[Vassilis Bekiaris]

Hello Joan,

this is not a bug. Since the entry was updated by the EntryProcessor, its lastUpdateTime is updated as well.

It sounds like your use case could take advantage of ExtendedMapEntry#setValueWithoutChangingExpiryTime method which was introduced in Hazelcast 5.2, maybe worth the upgrade?

Alternatively, if you want to stay on 4.2 line, you could try using `ExtendedMapEntry#setValue` with a ttl argument: you can have your EntryProcessor implement HazelcastInstanceAware, so you get a reference to the member, get the entry view for the given key and calculate a ttl that will maintain the same (more-or-less) expiry time. As a code sample of a HazelcastInstanceAware entry processor, you can have a look at https://github.com/hazelcast/hazelcast-code-samples/blob/master/enterprise/wan-replication/simulating-max-idle/src/main/java/SingleMaxIdleSimulator.java#L20-L52.

Cheers!

Vassilis

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