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From Ilya Lantukh <ilant...@gridgain.com>
Subject Re: Why is custom cacheStore.write() being called in clientMode?
Date Tue, 06 Jun 2017 22:59:04 GMT
Hi Rick,

Regarding your example: in Ignite Cache you can update keys 2 and 4 in the
same transaction without any problems, but it might be impossible to
perform a distributed transaction in DB behind CacheStore (it must
transactionally save key2 from node1 and key4 from node2). To solve this
problem, we put both keys into CacheStore from the same node - the one that
initiated transaction ("near node" in Ignite terminology).

Hope this helps.

On Tue, Jun 6, 2017 at 6:10 PM, Nikolai Tikhonov <ntikhonov@apache.org>

> Rick,
> > What you are saying is that I cannot update keys 2 and 4 in the same
> transaction, correct?
> No, it's will be update in the same transaction. I explained you why
> Ignite can't update store from dht nodes (nodes which own this data) and
> why Ignite propagates updates to store from client node.
> On Tue, Jun 6, 2017 at 5:42 PM, rick_tem <rvincent@temenos.com> wrote:
>> Hi Nikolai,
>> Thanks for your reply.  It is appreciated!  Thanks for your answer to 2) I
>> will look into it. 3) and 4) are really the same issue I am trying to
>> understand how it works.
>> With regards to 1) below, we aren't speaking about distributed databases,
>> but distributed caches that are java JVMs.  But isn't that what a JTA
>> transaction manager is supposed to do?  ie handle distributed
>> transactions?
>> if I enlist MQ and Jboss in the same transaction that is two seperate JVMs
>> and I believe should work with one atomic transaction...
>> But regardless, I believe this is what you are saying here:  Please
>> correct
>> me if I am wrong.  Say I have keys 1, 2, 3 on node 1 and keys 4, 5, 6 on
>> node 2.  What you are saying is that I cannot update keys 2 and 4 in the
>> same transaction, correct?  This is because they live in two different
>> JVMs...If this is the case, that is a severe limitation as then I need to
>> know which node my data is on.  What would your recommendation be here
>> then
>> for write-through cache?  Have everything replicated?  It is a requirement
>> that the transaction be rock solid in whatever model I implement.  I
>> cannot
>> afford to lose writes or have half-committed data.
>> Thanks,
>> Rick
>> --
>> View this message in context: http://apache-ignite-users.705
>> 18.x6.nabble.com/Why-is-custom-cacheStore-write-being-called
>> -in-clientMode-tp13309p13424.html
>> Sent from the Apache Ignite Users mailing list archive at Nabble.com.

Best regards,

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