I also roughly remember that we even generate different bytecode (at least when using compile time enhancement) depending on the persistence.xml version. Safest bet is to use version 2.0. Guess this was done to improve compatibility with older projects.
LieGrue, strub --- On Fri, 8/12/11, Rick Curtis <curti...@gmail.com> wrote: > From: Rick Curtis <curti...@gmail.com> > Subject: Re: Possibility to return detached objects from a query? > To: users@openjpa.apache.org > Date: Friday, August 12, 2011, 5:44 PM > ....I knew this sounded familiar. It > looks like I found this problem quite a > while back and haven't got around to fixing the bug. > > https://issues.apache.org/jira/browse/OPENJPA-1672 > > On Fri, Aug 12, 2011 at 11:23 AM, Michael Pflueger > <michael.pflue...@sma.de>wrote: > > > Seems that would be 1.0 then. > > > > See my other post containing a testcase/src folder > including a > > persistence.xml. > > > > I hope this helps reproducing the problem. > > > > Michael > > > > -----Ursprüngliche Nachricht----- > > Von: Michael Dick [mailto:michael.d.d...@gmail.com] > > Gesendet: Freitag, 12. August 2011 18:04 > > An: users@openjpa.apache.org > > Betreff: Re: Possibility to return detached objects > from a query? > > > > Some of the detach behavior depends on the version in > your persistence.xml > > file. It's kind of a shot in the dark, but are you > validating against > > version 2.0, or 1.0? > > > > -mike > > > > On Fri, Aug 12, 2011 at 9:56 AM, Michael Pflueger > > <michael.pflue...@sma.de>wrote: > > > > > Hi Rick, > > > > > > Yes, I'm using 2.2 trunk, ~1 week old. > > > > > > I did try LRS in the past, but as I encountered a > bug there I switched > > away > > > from it. > > > This bug seems to be fixed in trunk, but I could > only use LRS for > > Importing > > > data anyway, as our main DB is MySQL, which lacks > proper LRS support with > > > concurrent queries. > > > > > > Thus, I wrote a simple query chunker which loads > a chunk of results from > > > the db, provides an iterator, and upon reaching > the end automatically > > loads > > > the next chunk, etc. > > > > > > So, I could try LRS for the purpose of debugging > etc, but it should work > > > without them aswell. > > > > > > And Yes! After a quick check, with > CopyOnDetach=false, OpenJPA behaves as > > > expected and does not use more than about 30MB of > Heap space and most > > > importantly stays in that range. (as long as I > detach my entities :) > > > > > > Thanks! > > > > > > I'd still be interested whether it's a bug in the > copyOnDetach=true > > > codepath or if it is working as designed that the > manager keeps managed > > > copies on detachment? > > > > > > -----Ursprüngliche Nachricht----- > > > Von: Rick Curtis [mailto:curti...@gmail.com] > > > Gesendet: Donnerstag, 11. August 2011 16:11 > > > An: users@openjpa.apache.org > > > Betreff: Re: Possibility to return detached > objects from a query? > > > > > > Michael - > > > > > > > While I still wonder about why detaching my > entities doesn't reduce my > > > heap memory usage > > > You didn't mention what level of code you are > running on, but if it is > > > > 2.0, it might be a bug. Try setting the following > property: <property > > > name="openjpa.Compatibility" > value="CopyOnDetach=false"/> > > > > > > > also wonder whether there is a possibility > for a query to return > > detached > > > objects in the first place? > > > I'm not aware of one. That doesn't mean the > capability doesn't exist, I'm > > > just not aware of it :) > > > > > > > Calling detach() for every object looks to > be rather expensive > > > Correct, in some of our performance testing we > have found that detach is > > > quite expensive. I put in a property > LiteAutoDetach which is in place to > > > quickly detach the entire persistence context, > but unfortunately this > > > optimization isn't available for detaching single > instances. > > > > > > I know I missed an email you sent to this list a > number of days ago where > > > you were asking a very similar question. I don't > want to derail this > > > thread, > > > but have you looked at large result sets[1]? The > might simplify some of > > > your > > > loading code. > > > > > > > > > [1] > > > > > > > > http://openjpa.apache.org/builds/latest/docs/manual/manual.html#ref_guide_dbsetup_lrs > > > > > > Thanks, > > > Rick > > > > > > On Thu, Aug 11, 2011 at 2:06 AM, Michael > Pflueger > > > <michael.pflue...@sma.de>wrote: > > > > > > > Hi, > > > > > > > > While I still wonder about why detaching my > entities doesn't reduce my > > > heap > > > > memory usage, > > > > I also wonder whether there is a possibility > for a query to return > > > detached > > > > objects in the first place? > > > > This might be quite efficient for scenarios > where you need to read lots > > > of > > > > data but not update it or need any other > features of a managed entity. > > > > Calling detach() for every object looks to > be rather expensive, and > > above > > > > method would not only avoid that but could > possibly avoid some > > attachment > > > > overhead aswell. > > > > > ___________________________________________________ > > > > > > > > SMA Solar Technology AG > > > > Aufsichtsrat: Guenther Cramer > (Vorsitzender) > > > > Vorstand: Juergen Dolle, Roland Grebe, Uwe > Hertel, Pierre-Pascal Urbon, > > > > Marko Werner > > > > Handelsregister: Amtsgericht Kassel HRB > 3972 > > > > Sitz der Gesellschaft: 34266 Niestetal > > > > USt-ID-Nr. DE 113 08 59 54 > > > > WEEE-Reg.-Nr. DE 95881150 > > > > > ___________________________________________________ > > > > > > > > > > > > > > > > > -- > > > *Rick Curtis* > > > > > > > > > -- > *Rick Curtis* >
