ignite 2.8.0 LRU eviction not work as expected.

[bing <bi...@buffalo.edu>]

Hello:

I run the server from 2.8.0 bin package with default-config.xml.
Here is my java client code:

    Ignition.setClientMode(true);
    final CacheConfiguration cfg = new CacheConfiguration("lru-cache");
    cfg.setOnheapCacheEnabled(true);
    final LruEvictionPolicyFactory<String, String> plc = new
LruEvictionPolicyFactory<String, String>(20,20,20);
    cfg.setEvictionPolicyFactory(plc);
    final Ignite ignite = Ignition.start();
    cache = ignite.getOrCreateCache(cfg);

    for(int i = 0; i < 10; i++) {
      final String key = Integer.toString(i);
      cache.put(key, key);
    }

the output of cache.size(CachePeekMode.ONHEAP) is 1. and
cache.size(CachePeekMode.OFFHEAP) shows 10.

the output of cache.getEntry("0").getValue() will give "0", which I thought
it should be null, since I set LRU eviction.

In my user case, I want to use ignite as a pure in-memory cache. To enable
the LRU eviction, should I turn off the off-heap and could you please share
how to do it?

And since there is one item on the heap, may I know if there is a way to get
the cached item on the heap?

Moreover, I want to know if there is a way to set the max number of items
instead of the sizes in bytes.


Thanks!



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Re: ignite 2.8.0 LRU eviction not work as expected.

[Mikhail <mi...@gmail.com>]

Hi Bing,

it works as expected:
https://www.gridgain.com/docs/latest/developers-guide/memory-architecture/eviction-policies#on-heap-cache-eviction

you set eviction only for on-heap, records will never be evicted from the
off-heap memory, but only from on -heap.

Please see my example:
https://gist.github.com/Mikhail1988/679665d7bad89b604d14b073de30ddb4

If you want to evict data from off-heap you need to use:
https://www.gridgain.com/docs/latest/developers-guide/memory-architecture/eviction-policies#off-heap-memory-eviction

Thanks,
Mike.







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