Hi Azeez/Nuwan, On Fri, Jun 21, 2019 at 2:57 PM Afkham Azeez <az...@wso2.com> wrote:
> An item can get removed from the cache for two reasons: > > 1. Cache expiry. > A task runs periodically and checks the last accessed time of each cache > entry and removes it if the entry has not been accessed for sometime > This is what I expected/assumed too. (i.e. if a particular cache entry is kept being used forever, it should never be removed from cache [plz correct me if my understanding of ACCESSED type expiry is wrong] ) And I also have noticed that in some caches (I don't remember where) it runs a forceful cache clean up task periodically to remove these never-removable cache entries time to time. So that was the other part of my expectation/assumption. However, I ran a few tests with APIM gateway cache[1] with just 2 tokens. But results don't reflect above. Each cache entry has its own lifespan. That's correct. But they are removed after the configured cache timeout (individually based on their lifespan) even when they are kept being used. That means the ACCESSED type expiry is not honored, I assume. Is my understanding wrong? [1] https://github.com/wso2/carbon-apimgt/blob/master/components/apimgt/org.wso2.carbon.apimgt.impl/src/main/java/org/wso2/carbon/apimgt/impl/utils/APIUtil.java#L7487 p.s. what does setStoreByValue mean in [1]? Thanks, Bhathiya > > 2. Cache eviction > When cache capacity is reached and there is no more space to insert items, > then 25% of the items are (forcefully) evicted (even if they have not > expired). > > If the cache is periodically purged even ignoring the above two cases, > then it is incorrect. Such code didn't exist in the early versions of > caching that I implemented. > > Azeez > > On Fri, Jun 21, 2019 at 12:07 PM Nuwan Dias <nuw...@wso2.com> wrote: > >> Hi, >> >> I have heard about two mechanisms how the cache expires in WSO2 products. >> >> 1. Each cache entry has its individual lifespan specified in the cache >> timeout config (15m by default). >> 2. A scheduled job that runs periodically (based on the cache timeout) >> cleans the full cache on each run. This would mean that some cache entries >> expire sooner than the others. >> >> Which of the above is correct? Or is it completely different? Can we >> alter between the two based on a config? >> >> Thanks, >> NuwanD. >> >> -- >> *Nuwan Dias* | Director | WSO2 Inc. >> (m) +94 777 775 729 | (e) nuw...@wso2.com >> [image: Signature.jpg] >> > > > -- > *Afkham Azeez* | Vice President | WSO2 Inc. > (m) +94773320919 | (w) +94117435800 | (e) az...@wso2.com > GET INTEGRATION AGILE > Integration Agility for Digitally Driven Business > > -- *Bhathiya Jayasekara* *Technical Lead,* *WSO2 inc., http://wso2.com <http://wso2.com>* *Phone: +94715478185* *LinkedIn: http://www.linkedin.com/in/bhathiyaj <http://www.linkedin.com/in/bhathiyaj>* *Twitter: https://twitter.com/bhathiyax <https://twitter.com/bhathiyax>* *Blog: http://movingaheadblog.blogspot.com <http://movingaheadblog.blogspot.com/>*
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