Re: Slow Return on Paginated SelectQuery

From: Michael Gentry (mgentr..asslight.net)
Date: Sun Apr 12 2009 - 20:52:37 EDT

  • Next message: Kevin Menard: "Re: Slow Return on Paginated SelectQuery"

    Cayenne has to fetch the primary keys of your ~683k records first,
    which is why it is taking so long. After that, it will use the PKs to
    fetch all the records for each page (50 at a time in your case) you
    access. Eventually you'll have all ~683k in memory (if you have
    enough memory). This will be horribly inefficient. You should try to
    find a way to divide your data set up into smaller chunks that you can
    process.

    mrg

    On Sun, Apr 12, 2009 at 8:42 PM, Paul Logasa Bogen II <pl..amu.edu> wrote:
    > I have a table with ~683k entries in it. I have a maintenance task that
    > requires me to hit every entry. Since I know the results are much too big to
    > return all at once, I've set the page size to 50. However, Cayenne appears
    > to be attempting the full query first before falling back to paging. This is
    > taking nearly half an hour for it to fall back, at which point everything
    > works flawlessly. Is there a way to force the query to be paginated or to
    > reduce the timeout on a query?
    >
    > plb
    >



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