Could be a c3po or database driver bug. Are you using the latest versions? Martijn
On Fri, 2008-07-25 at 06:49 -0400, Chris Lewis wrote: > Yep, that solved it. > > <property name="hibernate.c3p0.max_statements">0</property> > > After that prepared statements work as normal. Doesn't the > hibernate.c3p0.max_statements directive help improve performance though? > I mean, wouldn't it if it didn't fall over ... ;-) > > Thanks Martijn, I'm glad I'm not crazy and will know to be wary of it in > the future. > > chris > > Martijn Brinkers wrote: > > This posting also report similar problems and it was 'solved' by > > disabling the statement cache. > > > > https://jira.jboss.org/jira/browse/JBPORTAL-1287 > > > > > > Martijn > > > > On Thu, 2008-07-24 at 22:57 -0700, Martijn Brinkers (List) wrote: > > > >> Sounds to me something related to the PreparedStatement cache. Do you > >> use c3po? If so did you specify hibernate.c3p0.max_statements? > >> > >> Martijn > >> > >> > >> On Thu, 2008-07-24 at 23:26 -0400, Chris Lewis wrote: > >> > >>> Ok, I've figured out what exactly is causing it and how to work around > >>> it. I can't say why, but perhaps a resident hibernate guru will know (it > >>> may even be a know issue or gotcha). First off, the quick fix. This > >>> query (and variations like load(), get(), and using the criteria api) > >>> cause the problem: > >>> > >>> Listing listing = (Listing)session.createQuery("from Listing lst > >>> where lst.id=:id") > >>> .setLong("id", Long.valueOf(sListingId)).uniqueResult(); > >>> > >>> This works as expected: > >>> > >>> Listing listing = (Listing)session.createQuery("from Listing lst > >>> where lst.id=" + sListingId) > >>> .uniqueResult(); > >>> > >>> It seems to come down to how hibernate handles the query results when > >>> the query is formed with a "raw" HQL string vs something like get(), > >>> load(), the criteria api, or using query parameters as I was initially > >>> doing. It also has something to do with the field being queried and > >>> seems to happen only on fields that exist in each of the tables. In my > >>> case the abstract super class Listing has the PK field "id", and the 2 > >>> subclasses also have a PK field named "id." Querying by any method other > >>> than "constructed strings" leads to the issue, while querying on another > >>> field in the super class, whose name is unique to that class, works fine. > >>> > >>> So the BIG question is why in the world does it work the first time and > >>> continue to work until the value one queries by changes? > >>> > >>> I'd also like to know if anyone has seen this before, and/or if it's a > >>> known issue. I'm using a slightly outdated version of hibernate > >>> (3.2.2.ga) and for all I know this may be fixed in more recent versions. > >>> My wrists are shot so I'll try tomorrow. If anyone knows of this or gets > >>> interested/bored enough to try it, please let me know. > >>> > >>> Thanks tons for all of your input. > >>> > >>> Sincerely, > >>> Chris Lewis > >>> > >>> Chris Lewis wrote: > >>> > >>>> Hello, > >>>> > >>>> I have a dispatcher that uses a hibernate session. The dispatcher is > >>>> auto bound and receives the session in the constructor. I'm using > >>>> tapestry-hibernate so that session instance is a proxy that gets the > >>>> real session for the current thread (right?). Now in testing my > >>>> dispatcher, I give it a url like: > >>>> > >>>> /MyContext/?limg=2 > >>>> > >>>> The dispatcher looks for "limg" and if found, queries the session > >>>> assuming that its value is the PK of a mapped entity. When I trigger the > >>>> dispatcher for the first time it works fine. If I refresh the page, > >>>> fine. If I change the value to something else, say 3, then it breaks > >>>> with a org.hibernate.InstantiationException: > >>>> > >>>> Cannot instantiate abstract class or interface: > >>>> com.mypackage.data.Listing > >>>> > >>>> If I change the value back to 2, the same thing happens! "Listing" is an > >>>> abstract class mapped as a super class entity via: > >>>> > >>>> @Entity > >>>> @Inheritance(strategy = InheritanceType.JOINED) > >>>> > >>>> Any clue what's going on here? Two things are perplexing me: > >>>> > >>>> 1) Querying mapped super classes is legal, and I in fact the same thing > >>>> on my Index page with no problem. > >>>> 2) The query works the first time, but as soon as the id changes it is > >>>> forever broken until I restart the container. > >>>> > >>>> Thanks in advance! > >>>> > >>>> chris > >>>> > >>>> > >>>> > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
