Re: server-to-client event push - Re: relationship query and cache refreshing in 3tier cayenne

From: Aristedes Maniatis (ar..sh.com.au)
Date: Thu May 15 2008 - 05:26:52 EDT

  • Next message: Andrus Adamchik: "Re: server-to-client event push - Re: relationship query and cache refreshing in 3tier cayenne"

    On 15/05/2008, at 7:43 AM, Andrus Adamchik wrote:

    > 1. Client sends a "give me events" request in the beginning of the
    > session (separate from data requests), and reads everything that
    > comes back.

    Three thoughts:

    1. Is your idea to have one queue per client, or a single queue with
    some sort of sequence numbering so a client can grab events later than
    a particular timestamp/sequence?

    2. Even without continuations the basic idea could still work if the
    client received these events attached to query results. So every time
    a client performs a query (or executes a special polling request)
    these events are received. Not quite so real-time, but possibly useful
    in many circumstances.

    3. Are the events here just refresh query cache events, or are we
    talking about 'invalidate record id 1234 from entity Artist' messages?
    Possibly that will generate too much traffic since the server will not
    know which clients have those entities already cached and will have to
    propagate all invalidate messages to all clients. I'm still a little
    hazy about whether the server has a copy of the same contexts as the
    client does, so perhaps it does know which records the client is
    holding, but I'm not sure how SHARED_CACHE impacts that.

    Ari

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