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    <p>There are two different ways this can happen, either with moxi or without moxi.</p> <p>Without Moxi (Smart Client)</p> <p>The the client makes a connection with Couchbase it will first get a list of all of the servers in the cluster and the vbucket map. It then makes a connection to each server in the cluster. When you do a multi-operation the client will consult with the vbucket map that it contains and figure out which vbucket the server belongs. If we have three servers then the client will put together up to three multi-operations and send each to the corresponding server that contains all of the keys in that multi-operation. Each server will respond to the client and the client will put all of the results together into on set of results.</p> <p>With Moxi</p> <p>In this case the client doesn't know about the cluster or the vbucket map, but moxi does. The client will send all keys to moxi and then moxi will take care of splitting them up and sending them to the appropriate servers.</p> <p>Sever Down Scenario:</p> <p>If a server is down or busy then all keys in that server specific multi-operation will fail. The client should return you the keys that it could get from the other servers and alert you of the error.</p> <p>Rebalancing Scenario:</p> <p>During a rebalance there is a small chance that a request will be sent to the wrong server. In this case the client should retry the operation on the correct server. During rebalance each client should receive a "fast-forward" vbucket map that says where all of the vbuckets will be after the rebalance. It will use the server in this vbucket map for the retry.</p>
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    1. COHmm kind of hard to understand atm... For the First part, as I can see from your writing, it seems like more than one network call can be done by client, also you said "send each to the corresponding server that contains all of the keys in that multi-operation" What if that kind of server doesn't exist? in Second part, you said "split them up and send to appropriate server" does this mean client connects to several servers and send appropriate requests? In Third part, if 3 keys, and 1 failed to get. Does whole request returns error? would like to know more in detail. Thank you
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    2. COI apologize for my answer being a little bit confusing. Your starting to ask more detailed questions so it would help if you could tell me which client you are using to connect to Couchbase with. That way I can better answer your questions.
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    3. COBy the client, you mean by the language I think... I haven't decided which library to use yet, but looking over spymemcached(JAVA) and libcouchbase(C++). seems like both acting pretty similar
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