The eviction in Infinispan is occurring much before the high water mark

[suhasan]

The eviction is occurring much before the high water mark is reached. For e.g. We set the High WaterMark to 5, and enable the file persistence. When we add first and second object to region there is no eviction, when we add the third object the first object get evicted and stored to file. Similarly if we add the 4th object the second object is evicted . Why is the persistence occurring on the third object only when we had set High water mark to 5 ?

We have an application making use of Infinispan cache. We have made use of programmatic configuration, so the configuration file cant be shared. But we can provide an update on the configurations used.

The file persistence is configured for the cache.

org.infinispan.config.Configuration.setEvictionMaxEntries = 5

org.infinispan.config.Configuration.setExpirationLifespan = 900000

org.infinispan.config.Configuration.setExpirationMaxIdle = InactiveTime

org.infinispan.config.CacheLoaderManagerConfig.setPassivation = true

org.infinispan.config.CacheLoaderManagerConfig.setPreload = false

org.infinispan.loaders.file.FileCacheStoreConfig.setCacheLoaderClassName = org.infinispan.loaders.file.FileCacheStore

org.infinispan.loaders.file.FileCacheStoreConfig.setPurgeOnStartup = false

So we expect the cache to evict the entries when the number of entries reach a value of 5. But the eviction is concurring for a value of 3 itself. This is the issue.

[wdfink]

Did you set other eviction properties?

What version do you use.

The eviction use ^2, so max-entries are changed to closest value to ensure it will never exeed max.

Could you try a larger value? Maybe 16 for a test. I suppose 5 is not a real scenario - only a test

[suhasan]

Hi Wolf-Dieter Fink,

Thanks for the quick response.

I am using Infinispan 5.1 release.

I Have set all the other properties to default.

I had reduced the max entries to 5 to understand more in details when the data will be persisted

Basically i was testing Persistence for Evicted data, when i came across this behavior.

Based on your response, the number of entries stored in the cache will be approximately based on the below formula

The number of entries in cache ^ 2 <= Eviction Max entry.

So for my testing when i put the max entry as 5, the number of entry stored in cache is 2 and the remaining entries will be evicted and be persisted.

Can you please confirm if my understanding is correct?

.

[wdfink]

I think the closest ^2 is 2^2=4. Maybe the eviction use < so eviction take effect after the third entry.

You might experiment with the power of ^2.

To be sure I need to have a look to the sources

But I'm sure I've seen eviction working

[suhasan]

Hi Wolf-Dieter Fink,

Thanks for confirming.