Re: Help! I need the magic no-cache recipe

From: Chris Gamache (cgamach..mail.com)
Date: Tue Jul 08 2008 - 08:59:47 EDT

  • Next message: Andrus Adamchik: "Re: Help! I need the magic no-cache recipe"

    Any ideas on a solution to this problem?

    I can now say, beyond a shadow of a doubt, that cayenne is caching
    relational requests when the same keys are used to retrieve the parent data
    object. The rows returned from the toMany request are volatile, and need to
    be re-queried when a new SelectQuery is run.

    Please advise. This has moved to a critical deficiency in my application. It
    is always possible that the problem exists between the keyboard and the
    chair. Please help me understand how to force Cayenne to exhibit the desired
    behavior.

    On Wed, Jun 18, 2008 at 3:57 PM, Chris Gamache <cgamach..mail.com> wrote:

    > I'm sorry. I definitely was vague!!! Let me try again...
    >
    > someQuery.addPrefetch("thisRelationIsaToManyList");
    > context.execute(someQuery); //throws ClassCastException in the part of
    > the code where it is trying to prefetch.
    >
    > How do I make certain the cayenne is not caching data from a relation
    > that returns a ToManyList? Probably not addPrefetch() because it
    > throws a ClassCastException.
    >
    >
    > On Wed, Jun 18, 2008 at 12:25 PM, Robert Zeigler
    > <robert..uregumption.com> wrote:
    > > A ToManyList isn't a DataObject. It's a list of DataObjects. :)
    > > Just treat it like a regular list.
    > >
    > > Robert
    > >
    > > On Jun 18, 2008, at 6/1811:18 AM , Chris Gamache wrote:
    > >
    > >> also........ :)
    > >>
    > >> How do I deal with a ToManyList prefetch?
    > >>
    > >> I'm getting a ClassCastException trying to cast a ToManyList to a
    > >> DataObject.
    > >>
    > >> On Mon, Jun 16, 2008 at 10:36 AM, Chris Gamache <cgamach..mail.com>
    > >> wrote:
    > >>>
    > >>> For clarification:
    > >>>
    > >>> DataContext.invalidateObjects(...) What strategy would you use to
    > >>> invalidate everything?
    > >>>
    > >>> For .addPrefetch(String s), does s need to match the relation name in
    > >>> the xml files?
    > >>>
    > >>> And on a related note...
    > >>>
    > >>> What does "Max. Number of Shared Objects" actually limit, and what
    > >>> does the "Use Shared Cache" toggle do?
    > >>>
    > >>> If I set my "Max. Number of Shared Objects" to zero, or unchecked "Use
    > >>> Shared Cache" would that force Cayenne to hit the database every time
    > >>> a query was executed or a relation was fetched?
    > >>>
    > >>>
    > >>>
    > >>>
    > >>> On Tue, Jun 10, 2008 at 3:03 AM, Andrus Adamchik <
    > andru..bjectstyle.org>
    > >>> wrote:
    > >>>>
    > >>>> To control relationship refresh you can either use
    > >>>> DataContext.invalidateObjects(..) or plan a bit ahead and refresh it
    > >>>> together with the query that fetched the root object by using
    > >>>> prefetching on
    > >>>> that relationship. E.g.
    > >>>>
    > >>>> someQuery.addPrefetch("relatedRows");
    > >>>> List rows = context.performQuery(someQuery);
    > >>>>
    > >>>> Judging from your example the prefetch option should be exactly what
    > you
    > >>>> need.
    > >>>>
    > >>>> Andrus
    > >>>>
    > >>>>
    > >>>> On Jun 9, 2008, at 11:08 PM, Chris Gamache wrote:
    > >>>>>
    > >>>>> Using Cayenne 2.0.3 ...
    > >>>>>
    > >>>>> I'm having problems when I use an accessor to get rows from a related
    > >>>>> table. It pulls fresh data the first time I use the accessor, but if
    > >>>>> data is modified outside of the Java application, it is not reflected
    > >>>>> the next time I use the accessor in a different execution stack
    > within
    > >>>>> the same JVM.
    > >>>>>
    > >>>>> List rowsA = context.performQuery(someQuery);
    > >>>>> ...
    > >>>>> SomeTable dataSetA = rowA.getRelatedRows();
    > >>>>> //object rowA and dataSetA and someQuery pass out of scope
    > >>>>> ...
    > >>>>> //Data is Modified directly on the database, not in Java application
    > >>>>> ...
    > >>>>> List rowsB = context.performQuery(theSameQuery);
    > >>>>> ...
    > >>>>> SomeTable expectedModifiedButGotSetA = rowB.getRelatedRows();
    > >>>>>
    > >>>>>
    > >>>>> The primary key which the relation uses to get the related data
    > >>>>> doesn't change from rowsA to rowsB. We're looking at the same related
    > >>>>> rowset, just updated data.
    > >>>>>
    > >>>>> I would like to know what is the magic no-cache recipe to force that
    > >>>>> particular accessor to always pull fresh data from the database...
    > >>>>>
    > >>>>> It appears that SelectQuery doesn't suffer from the same problem.
    > >>>>>
    > >>>>> I'm sure there's some configuration switches that I can trip, but
    > >>>>> there are several places caching policies can be modified and several
    > >>>>> confusingly similar yet different options to choose from.
    > >>>>>
    > >>>>
    > >>>>
    > >>>
    > >
    > >
    >



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