In Ignite 1.x vs 2.x, when we get notified about an eviction (from cache 
events),  will Ignite literally delete the entry, or can they be remain  for 
certain period and later get wiped out.

The implementation of eviction from 1.x to 2.x is a different, new one?


From: Denis Mekhanikov [mailto:dmekhani...@gmail.com]
Sent: Monday, November 05, 2018 7:22 AM
To: user
Subject: Re: Is there Ignite Eviction low water mark

This email is from an external source - exercise caution regarding links and 
attachments.
Hi!

Ignite 2.x has a mechanism called page 
eviction<https://apacheignite.readme.io/v2.6/docs/evictions#section-off-heap-memory>.
 It's configured using 
DataRegion#pageEvictionMode<https://ignite.apache.org/releases/latest/javadoc/org/apache/ignite/configuration/DataRegionConfiguration.html#setPageEvictionMode-org.apache.ignite.configuration.DataPageEvictionMode->.
Page eviction removes entries from a data region until either 
DataRegionConfiguration#evictionThreshold<https://ignite.apache.org/releases/latest/javadoc/org/apache/ignite/configuration/DataRegionConfiguration.html#setEvictionThreshold-double->
 is reached,
or 
DataRegionConfiguration#emptyPagesPoolSize<https://ignite.apache.org/releases/latest/javadoc/org/apache/ignite/configuration/DataRegionConfiguration.html#setEmptyPagesPoolSize-int->
 pages are available in the free list.
It's applied only when persistence is disabled. Otherwise data is just spilled 
to disk.

Ignite 1.x has a different kind of eviction, since it doesn't have page memory 
nor data regions.
It removes data until occupied memory is bellow 
LruEvictionPolisy#maxSize<https://ignite.apache.org/releases/1.9.0/javadoc/org/apache/ignite/cache/eviction/lru/LruEvictionPolicy.html#setMaxSize(int)>.
This is similar to on-heap eviction 
policy<https://apacheignite.readme.io/v2.6/docs/evictions#section-on-heap-cache>
 in Ignite 2.x, but you don't need to use it
unless you know exactly what you're doing and what an on-heap cache is.

Denis

пт, 2 нояб. 2018 г. в 21:35, HEWA WIDANA GAMAGE, SUBASH 
<subash.hewawidanagam...@fmr.com<mailto:subash.hewawidanagam...@fmr.com>>:
Hi all,
This is to understand how eviction works in Ignite cache.

For example, let’s say the LRU eviction policy is set to max 100MB. Then, when 
the cache size reached 100MB, how much of LRU entries will get evicted ? Is 
there any low water mark/percentage ? Like eviction policy will remove 20% of 
the cache, and then let it again reach back to 100MB to clean up again.

Also please confirm whether the behavior is same in Ignite 1.9 vs 2.6.

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