Re: Imports

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Sun Mar 09 2008 - 13:45:46 EDT

  • Next message: Malcolm Edgar: "Re: Imports"

    BTW, if there's no commit or rollback, and the transaction stays open
    indefinitely, this would result in quick connection pool exhaustion.
    So why would you do that?

    Andrus

    On Mar 9, 2008, at 7:19 PM, Andrus Adamchik wrote:
    > This could be a DB artifact. E.g. with MySQL MyISAM tables. Which DB
    > are you using?
    >
    > Andrus
    >
    > On Mar 8, 2008, at 5:53 AM, Malcolm Edgar wrote:
    >
    >> I have been playing around this in a web context, and what I am
    >> finding with a user created Transaction, if the DataContext commits
    >> the changes, unless the Transaction explicitly performs a rollback
    >> the
    >> changes will be committed to the database.
    >>
    >> This is not what I was expecting, but I am wondering if this is an
    >> artifact of the thread pool, ie maybe the same thread is coming back
    >> of the pool.
    >>
    >> regards Malcolm Edgar
    >>
    >> On Tue, Feb 19, 2008 at 8:31 PM, Malcolm Edgar <malcolm.edga..mail.com
    >> > wrote:
    >>> Great! Thanks for that.
    >>>
    >>> regards Malcolm Edgar
    >>>
    >>>
    >>>
    >>> On Feb 19, 2008 11:18 AM, Andrus Adamchik <andru..bjectstyle.org>
    >>> wrote:
    >>>> Just use your own transactions, then 'commitChanges' turns into
    >>>> 'flush':
    >>>>
    >>>> http://cayenne.apache.org/doc/understanding-transactions.html
    >>>>
    >>>> Andrus
    >>>>
    >>>>
    >>>> On Feb 18, 2008, at 7:49 AM, Malcolm Edgar wrote:
    >>>>
    >>>>> Hi Ari,
    >>>>>
    >>>>> thanks for the response. This would be a very good 3.0 feature
    >>>>> if it
    >>>>> is not already present.
    >>>>>
    >>>>> In Hibernate this functionality is performed as a flush operation,
    >>>>> where CRUD operations are performed against the transaction but
    >>>>> are
    >>>>> not actually committed.
    >>>>>
    >>>>> Would this would cause issues with Cayenne PK generation
    >>>>> strategy, are
    >>>>> the highest/last table id values they maintained in memory?
    >>>>>
    >>>>> regards Malcolm Edgar
    >>>>>
    >>>>> On Feb 18, 2008 3:16 PM, Aristedes Maniatis <ar..sh.com.au>
    >>>>> wrote:
    >>>>>>
    >>>>>> On 18/02/2008, at 2:07 PM, Malcolm Edgar wrote:
    >>>>>>
    >>>>>>> Is there a way in Cayenne, possibly using Transactions, that
    >>>>>>> we can
    >>>>>>> perform this import, do inserts and queries against the
    >>>>>>> transaction
    >>>>>>> and only commit/rollback at the end?
    >>>>>>
    >>>>>> Subclass the Cayenne context, override performQuery and add in
    >>>>>> your
    >>>>>> own custom code there to look for new objects within the context?
    >>>>>> There is almost certainly a way to have a database transaction
    >>>>>> cross
    >>>>>> several Cayenne commits as well, but I can't assist there.
    >>>>>>
    >>>>>> In fact we've done this several times in our application and I
    >>>>>> was
    >>>>>> just thinking the other day whether this might be an option in
    >>>>>> a new
    >>>>>> generified performQuery and might be useful to be pushed into
    >>>>>> Cayenne.
    >>>>>>
    >>>>>>
    >>>>>> Ari Maniatis
    >>>>>>
    >>>>>>
    >>>>>> -------------------------->
    >>>>>> ish
    >>>>>> http://www.ish.com.au
    >>>>>> Level 1, 30 Wilson Street Newtown 2042 Australia
    >>>>>> phone +61 2 9550 5001 fax +61 2 9550 4001
    >>>>>> GPG fingerprint CBFB 84B4 738D 4E87 5E5C 5EFA EF6A 7D2E 3E49
    >>>>>> 102A
    >>>>>>
    >>>>>>
    >>>>>>
    >>>>>
    >>>>
    >>>>
    >>>
    >>
    >
    >



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