Re: refreshing prefetched objects.

From: Hans Pikkemaat (h.pikkemaa..si-solutions.nl)
Date: Wed Sep 08 2010 - 08:31:03 UTC

  • Next message: Hans Pikkemaat: "Re: refreshing prefetched objects."

      Hi,

    I did not explain my test case in enough detail.

    I have table testhpi, testhpi2 and testhpi3.

    There are relationships

         testhpi: testhpi2Array
         testhpi: testhpi3Array
         testhpi2: testhpi3Array

    I use a joint prefetches

         query.addPrefetch("testhpi2Array").setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);
         query.addPrefetch("testhpi2Array.testhpi3Array").setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);

    At some point I run the query and get correct results.
    It runs one big query where all records are retrieved.

    But at some point I also retrieve the testhpi3 records through the teshtpi.testhpi3Array releationship.
    There is no prefetch for this one so a separate query is run and I get the correct results. Actually I
    get the same objects as in the big query.

    Now it comes.

    I delete a record from testhpi3 and reinsert it.

    If I now run the first query the query is executed and the objects are refreshed.
    One object is replaced with a new one as it was deleted and re-inserted.
    This is all good.

    But if I run the second query it is not re-executed (no prefetch?) and I get an old result.
    This seems logical as there is no prefetch.
    So I added the prefetch

         query.addPrefetch("testhpi2Array").setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);

    But now I get this exception

    Exception in thread "main" org.apache.cayenne.CayenneRuntimeException: [v.2.0.4 October 12 2007] Query exception.
         at org.apache.cayenne.access.DataDomainQueryAction.nextQueryException(DataDomainQueryAction.java:428)
         at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:280)
         at org.apache.cayenne.access.DataDomainQueryAction.runQuery(DataDomainQueryAction.java:301)
         at org.apache.cayenne.access.DataDomainQueryAction.access$000(DataDomainQueryAction.java:60)
         at org.apache.cayenne.access.DataDomainQueryAction$1.transform(DataDomainQueryAction.java:273)
         at org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:836)
         at org.apache.cayenne.access.DataDomainQueryAction.runQueryInTransaction(DataDomainQueryAction.java:270)
         at org.apache.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:110)
         at org.apache.cayenne.access.DataDomain.onQuery(DataDomain.java:746)
         at org.apache.cayenne.util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:217)
         at org.apache.cayenne.access.DataContextQueryAction.execute(DataContextQueryAction.java:54)
         at org.apache.cayenne.access.DataContext.onQuery(DataContext.java:1395)
         at org.apache.cayenne.access.DataContext.performQuery(DataContext.java:1384)
         at cayenne.TryStuff.go(TryStuff.java:60)
         at cayenne.TryStuff.main(TryStuff.java:100)
    Caused by: java.lang.IllegalArgumentException: No inheritance - there must be only one override set
         at org.apache.cayenne.access.jdbc.DataRowPostProcessor.<init>(DataRowPostProcessor.java:126)
         at org.apache.cayenne.access.jdbc.DataRowPostProcessor.createPostProcessor(DataRowPostProcessor.java:113)
         at org.apache.cayenne.access.jdbc.SelectAction.performAction(SelectAction.java:84)
         at org.apache.cayenne.access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:59)
         at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:273)
         ... 13 more

    What am I doing wrong?

    tx

    Hans

    On 9/7/10 4:23 PM, Hans Pikkemaat wrote:
    > Indeed very strange.
    >
    > I'm trying to reproduce now using a simple table structure but here
    > it works fine.
    >
    > If I find something I'll let you know.
    >
    > Hans
    >
    > On 9/7/10 4:06 PM, Andrus Adamchik wrote:
    >> Very strange. Prefetching always refreshes related objects.
    >>
    >> Andrus
    >>
    >> On Sep 7, 2010, at 7:52 AM, Hans Pikkemaat wrote:



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