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From Thomas Mahler <thm...@web.de>
Subject Re: Oracle 9i BLOB malfunction / 4k mystery (issue OJB170)
Date Thu, 15 May 2003 19:14:52 GMT
Hi angain

Lance Eason wrote:
> I'll answer the first question.  It is most definitely an Oracle bug.
> Regardless it is important that OJB address it in my opinion.  

+1

> Users
> using JDBC directly can work around this bug, users using OJB
> currently cannot.  

As it's pretty OK to use OJB to obtain JDBC connections you can use OJB 
*and* use direct JDBC calls to work around this problem.

> That creates a decision point when BLOB/CLOB data
> is required of use Oracle or use OJB and to most people the DBMS is
> going to be the higher priority.

don't agree, see above.

> 
> And yes the OCI driver does not exhibit this bug but it is not always
> possible to use the OCI driver.  First it requires an Oracle client
> installation on each machine and second it is native code and at
> least for Oracle 8.1.7 is flaky (many, many SEGFAULTs in our recent
> load testing).

As I mentioned in my other mail, Oracle seems to have fixed the 
CLOB/BLOB problems with the thin driver in their latest release!

I think we should further investigate this before launching bug fix 
rampage. ;-)

cheers,
thomas

> 
> -----Original Message----- From: Torsten Schlabach
> [mailto:TSchlabach@gmx.net] Sent: Thursday, May 15, 2003 6:29 AM To:
> ojb-dev@db.apache.org Subject: Re: Oracle 9i BLOB malfunction / 4k
> mystery (issue OJB170)
> 
> 
> Folks,
> 
> if I get this right, we still don't have a *real* solution to this,
> do we? I found that Per-Olof's CLOB patch for using the thin driver
> made it to the CVS, but I understand it only fixes this for text < 4
> KB, right?
> 
> So first of all I thought it was a good idea to enter an issue in the
> bug database at http://scarab.werken.com/scarab/issues/id/OJB170
> (which became OJB170).
> 
> So to me there are at two questions right now:
> 
> 1. Is this an OJB bug, an Oracle bug or both? 2. How do we *want* do
> handle this at all?
> 
> What I mean is: To what column type would I map a String object that
> I except to grow very large (i.e. some dozends KB of text)?
> 
> I might map it to JDBC type CLOB which would be closest to reality
> but this will break with a class cast exception (you cannot cast a
> string to a java.sql.Clob).
> 
> If you map it to anything else such as LONGVARCHAR Oracle will not
> care but this will probably break other things.
> 
> In fact it might depend on your application what you want back in
> your bean when using a CLOB column: You either might want to get a
> stream you can read from in some other place or you might want to
> just get the stuff into a String and not care about it any more
> (which would make your application code much less Oracle specific by
> the way).
> 
> This is essentially two different JDBC types needed for the same type
> of DB column. Does the framework support this at all? I am wrong in
> any assumption?
> 
> Torsten
> 
> P.S.: I would like to post this as a comment in Scarab, but I did not
> yet find out how to edit the issue. I was able to submit it though.
> Any help appreciated.
> 
> Original Message: ----------------- From: Thomas Poeschmann
> t.poeschmann@exxcellent.de Date: Mon, 12 May 2003 16:05:08 +0200 To:
> ojb-dev@db.apache.org Subject: Re: Oracle 9i BLOB malfunction / 4k
> mystery
> 
> 
> Hi there,
> 
> 
>> Michael Mogley wrote: Thomas Poeschmann says on the list that he
>> almost has a solution, using the above method I presume.
> 
> 
> Yes, of course using the SELECT FOR UPDATE. Sorry for promising
> posting code but not doing it, but I will try to find it this
> evening. It is probably just for reference for you, since you already
> have it.
> 
> 
>> Are there other dbmses and drivers that exhibit the same irregular
>>  behavior regarding LOBĀ“s.
> 
> 
> Not that I know. Sometimes it is different to call one of the methods
> on a statement to bring certain Java objects in. For example passing
> an array in as a String. But I have never seen anything hard as
> Oracle XLOBs ;)
> 
> 
>> Unfortunatly, our solution (apart from the the fix submitted)
>> currently consists of changing to the oci driver. Sad but true.
> 
> 
> Which has other drawbacks, but well... Other ORM can not handle it
> either with thin, by the way ;)
> 
> Kind regards,
> 
> Thomas
> 
> 
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