Re: Database replication and caching

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Wed Aug 02 2006 - 10:09:21 EDT

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    A shared cache can be cleaned up by doing
    DataDomain.getSharedSnapshotCache().clear(). Also I am in the process
    of implementing a pluggable externally managed cache in 3.0:

    http://issues.apache.org/cayenne/browse/CAY-613

    Andrus

    On Aug 2, 2006, at 2:41 AM, Borut BolÄina wrote:

    > We are at architectural/design phase (cycle zero). No decision has
    > yet been made. Is there an example for invalidating cache somewhere?
    >
    > bye,
    > Borut
    >
    > On 31.7.2006 20:29, Tore Halset wrote:
    >> Hello.
    >>
    >> On Jul 31, 2006, at 17:52, Borut BolÄina wrote:
    >>
    >>> I need an advice on using Cayenne in an environment where two
    >>> PostgeSQL databases are configured to replicate from each other
    >>> for failover capability.
    >>
    >> Are you using Sequoia[1] or slony[2] or creating your own solution?
    >>
    >>> I am thinking of two Cayenne enabled applications (load
    >>> distribution) which insert records in one of those two databases.
    >>> Application one (A1) inserts in database one (DB1) and
    >>> application two (A2) inserts in database two (DB2).
    >>>
    >>> The insertion, deletion or update will cause Java triggers in
    >>> PostgreSQL to call appropriate Java method in the application. If
    >>> for any reason one of the databases is down for some time, the
    >>> replication mechanism will bring the second database up-to date
    >>> which will trigger invocations of the Java methods, so the second
    >>> application will be in the correct state also.
    >>>
    >>> As long as triggers do not modify records, everything should be
    >>> ok with Cayenne. In case, which I don't foresee now, the records
    >>> will be modified on database level, all DataContexts should be
    >>> invalidated, am I right?
    >>
    >> Cayenne has its own way of syncronizing cache[3] between app
    >> instances. You could also invalidate cache manually.
    >>
    >> - Tore.
    >>
    >> [1] http://sequoia.continuent.org/HomePage
    >> [2] http://gborg.postgresql.org/project/slony1/
    >> [3] http://cwiki.apache.org/CAYDOC/configuring-caching-behavior.html
    >>
    >>
    >
    > --
    > <blog-logo.gif>
    >
    > --
    > NakljuÄna izjava tedna iz tednika Mladina:



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