Message-Id: <4.1.19990707014452.00bf67b0@crunk.net>
Date: Wed, 07 Jul 1999 01:48:33 -0700
To: pgsql-interfaces@postgreSQL.org
From: Rolland Crunk <rc@aenet.net>
Subject: Re: [INTERFACES] JDBC - large objects
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Update. This particular problem is resolved. Here what it was:

The failing code as per my original posting went something like this:

	PreparedStatement statement = conn.prepareStatement("...");
		:		:
	//  add values to the prepared statement
		:		:
	conn.setAutoCommit(false);
	statement.executeUpdate("...");
	conn.commit();

When I changed it to go something like this:

	conn.setAutoCommit(false);
	PreparedStatement statement = conn.prepareStatement("...");
		:		:
	//  add values to the prepared statement
		:		:
	statement.executeUpdate("...");
	conn.commit();

The "ERROR:  lo_write: invalid large obj descriptor (0)" problem went away.

To summarize, autocommit needs to be turned off prior to statement creation.
(at least for prepared statements).

rc

At 02:03 AM 7/6/99 -0700, Rolland Crunk wrote:
>
>
>I am having some problem getting the jdbc driver to work properly with
>large objects using standard jdbc interfaces.  The tables are pretty much
>standard relational tables except for one column that I serialize 
>implementations of the java.security.acl.Acl as objects into. 
>
>The error I get is: ERROR:  lo_write: invalid large obj descriptor (0)
>
>This was the same error I got running the blobtest until I applied Tatsuo 
>Ishii's
>patch I found in the mailing list archives. I tried the same thing in my code
>(turn on explicit transactions when storing a blob) but it doesn't seem to
>have any effect.
>
>I have tried defining the acl field in my create table statement as both:
>
>	:	:
>	acl	oid,
>	:	:
>
>and
>
>	:	:
>	acl	char[]
>	:	:
>
>And see same thing.
>
>The same (java) code runs fine using Oracle 8 and their thin driver. 
>
>I guess what I need to know is: is what I am trying to do possible using
>PostgreSQL/JDBC without using the PostgreSQL extensions? (not an
>option for me).  If so, what should I use for serialized columns in the
>create table sql statement?  Can it be done without turning off autocommit?
>
>Thanks in advance for any help anyone can provide.
>
>Cordially,
>
>rc
>
>ps: My environment is:
>
>	Solaris 2.7 (intel)
>	jdk 1.2 (jdk 1.1 fares no better)
>	PostgreSQL 6.5