Re: Performance Tuning in a Web App

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Wed Apr 13 2005 - 21:04:29 EDT

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    On Apr 13, 2005, at 6:12 PM, Fredrik Liden wrote:

    > I'd like to query a table for a thousand or so entries (which in turn
    > has a set of relations to other entries/tables. I need to process each
    > entry one by one but after that I don't need that entry.
    >
    > According to the note under Performance Tuning -> 11.3 Iterating
    > Through
    > Data Rows: An Application with Web GUI is NOT a good candidate for
    > implementation using ResultIterators.

    I guess only the first part of this note (about avoiding keeping open
    ResultIterators between requests) makes sense. The statement you quote
    is too broad and should probably be removed.

    > Is it not a good candidate even if the query/processing will take place
    > in only one jsp page or one servlet?

    If the processing happens in one request, it should be ok... You may
    need to increase the size of the connection pool to avoid pool timeout
    errors.

    In memory processing is likely an option too (depending on how many
    related objects are attached to that one thousand objects that you
    fetch)...

    There is also a patch by Derek Rendall to minimize memory use when
    doing such processing with paginated query -
    http://objectstyle.org/jira/secure/ViewIssue.jspa?key=CAY-294 . We will
    include it in Cayenne in some form, but I can't say when.

    Andrus



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