Hi, Yes, write behind buffer gets locks on entries which stores between loading to CacheStore. So that this entries cannot be evicted.
If "get" invocation can not find value in cache, it will try to get value from CacheStore. On Fri, Oct 14, 2016 at 6:55 PM, Pradeep Badiger <pradeepbadi...@fico.com> wrote: > I have some log statements in the load() which gets called when there is > no entry in the cache or write behind buffer. What I learnt is that there > is a write behind buffer that holds on to the entries (even the evicted > ones) and whenever there is a get() for an entry, ignite looks at both the > cache and the write behind buffer and loads it. If it doesn’t find it in > any of the two, it then uses the read through mechanism to load the entry > from the store. > > > > Thanks, > > Pradeep V.B. > > > > *From:* Vladislav Pyatkov [mailto:vpyat...@gridgain.com] > *Sent:* Friday, October 14, 2016 4:25 AM > > *To:* user@ignite.apache.org > *Subject:* Re: Evicted entry appears in Write-behind cache > > > > Hi Paradeep, > > > > Why are you think, what the entry could not be read through your > persistence storage: > > > > *.setReadThrough(stateQoS.isReadThroughEnabled()) * > > > > When cache can not get data from in memory, it will try to get data from > storage, which configured as "ReadThrough". > > > > On Thu, Oct 13, 2016 at 6:41 PM, Pradeep Badiger <pradeepbadi...@fico.com> > wrote: > > Hi Vladislav, > > > > Please see the below cache configuration. > > > > LruEvictionPolicy > evictionPolicy = new LruEvictionPolicy<>(getIntProperty(envConfig, > CACHE_SIZE, 10000)); > > cacheConfiguration > > > .setEvictionPolicy(evictionPolicy) > > > .setWriteBehindFlushSize(getIntProperty(envConfig, CACHE_WB_FLUSH_SIZE, > 0)) > > > .setWriteBehindBatchSize(getIntProperty(envConfig, CACHE_WB_BATCH_SIZE, > 200)) > > > .setWriteBehindEnabled(stateQoS.isWriteBehindEnabled()) > > > .setWriteBehindFlushFrequency(getIntProperty(envConfig, > CACHE_WB_FLUSH_FREQ_MS, 5000)) > > . > setWriteBehindFlushThreadCount(getIntProperty(envConfig, > CACHE_WB_FLUSH_THREADS, 10)) > > > .setCacheStoreFactory(new StateCacheStoreFactory<K, V>(cacheName, > > > storageManager)) > > > .setName(cacheName) > > > .setReadThrough(stateQoS.isReadThroughEnabled()) > > > .setWriteThrough(stateQoS.isWriteThroughEnabled()); > > > > Thanks, > > Pradeep V.B. > > > > *From:* Vladislav Pyatkov [mailto:vldpyat...@gmail.com] > *Sent:* Wednesday, October 12, 2016 2:59 AM > > > *To:* user@ignite.apache.org > *Subject:* Re: Evicted entry appears in Write-behind cache > > > > Hi Pradeep, > > > > Could you please provide cache configuration? > > > > On Tue, Oct 11, 2016 at 6:57 PM, Denis Magda <dma...@gridgain.com> wrote: > > Looks like that my initial understanding was wrong. There is a related > discussion > > http://apache-ignite-users.70518.x6.nabble.com/Cache- > read-through-with-expiry-policy-td2521.html > > > > — > > Denis > > > > On Oct 11, 2016, at 8:55 AM, Pradeep Badiger <pradeepbadi...@fico.com> > wrote: > > > > Hi Denis, > > > > I did the get() on the evicted entry from the cache, it still returned me > the value without calling the load() on the store. As you said, the entry > would be cached in the write behind store even for the evicted entry. Is > that true? > > > > Thanks, > > Pradeep V.B. > > *From:* Denis Magda [mailto:dma...@gridgain.com <dma...@gridgain.com>] > *Sent:* Monday, October 10, 2016 9:13 PM > *To:* user@ignite.apache.org > *Subject:* Re: Evicted entry appears in Write-behind cache > > > > Hi, > > > > How do you see that the evicted entries are still in the cache? If you > check this by calling cache get like operations then entries can be loaded > back from the write-behind store or from your underlying store. > > > > — > > Denis > > > > On Oct 8, 2016, at 1:00 PM, Pradeep Badiger <pradeepbadi...@fico.com> > wrote: > > > > Hi, > > > > I am trying to evaluate Apache Ignite and trying to explore eviction > policy and write behind features. I am seeing that whenever a cache is > configured with eviction policy and write behind feature, the write behind > cache always have all the changed entries including the ones that are > evicted, before the write cache is flushed. But soon after it is flushed, > the store loads again from DB. Is this the expected behavior? Is there a > documentation on how the write behind cache works? > > > > Thanks, > > Pradeep V.B. > > This email and any files transmitted with it are confidential, proprietary > and intended solely for the individual or entity to whom they are > addressed. If you have received this email in error please delete it > immediately. > > > > This email and any files transmitted with it are confidential, proprietary > and intended solely for the individual or entity to whom they are > addressed. If you have received this email in error please delete it > immediately. > > > > > > > > -- > > Vladislav Pyatkov > > This email and any files transmitted with it are confidential, proprietary > and intended solely for the individual or entity to whom they are > addressed. If you have received this email in error please delete it > immediately. > > > This email and any files transmitted with it are confidential, proprietary > and intended solely for the individual or entity to whom they are > addressed. If you have received this email in error please delete it > immediately. > -- Vladislav Pyatkov
