DBD::Pg's $dbh->func( "/path/to/file", 'lo_import' ) fails silently

I would suggest you join the Perl DBI mailing list and ask your question
there. There are some quite capable people in that group who could help
you troubleshoot this issue.

It's called dbi-users@perl.org. Look at
http://lists.cpan.org/showlist.cgi?name=dbi-users, where it tells you
how to subscribe.

-Will

________________________________

From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org] On Behalf Of Kynn Jones
Sent: 18 March 2009 12:01
To: pgsql-general General
Subject: [GENERAL] DBD::Pg's $dbh->func( "/path/to/file", 'lo_import' )
fails silently

I'm trying to use Perl's DBD::Pg module to import a file as a large
object. For this I'm using the following:

my $oid = $dbh->func( "/absolute/path/to/file", 'lo_import' );

When I do this, a new record is added to pg_largeobject, with a
proper-looking non-null loid, but the data field remains empty, and the
variable $oid above gets a return value of undef, i.e. the call to func
fails. No error warning is ever emitted, as far as I can tell.
($dbh->errstr returns undef.) FWIW, the file passed as the first
argument is world-readable, and the full path to it is world-accessible.

I've read the documentation for Perl's DBI and DBD::Pg modules, but I
can't find any information that will enable me to troubleshoot/debug
this further. Any suggestions would be greatly appreciated!

TIA!

Kynn

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I'm trying to use Perl's DBD::Pg module to import a file as a large object.
For this I'm using the following:
my $oid = $dbh->func( "/absolute/path/to/file", 'lo_import' );

Works fine for me. What version of DBD::Pg are you using? Try something
recent if you are using something old. You can also set the trace
level to see what's going on behind the scenes:

$dbh->trace(10)

If you can't get it to work, please send a small, self-contained script that
duplicates the problem.

- --
Greg Sabino Mullane greg@turnstep.com
End Point Corporation
PGP Key: 0x14964AC8 200903181557
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
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On Wed, Mar 18, 2009 at 3:57 PM, Greg Sabino Mullane <greg@turnstep.com>wrote:

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I'm trying to use Perl's DBD::Pg module to import a file as a large

object.

For this I'm using the following:
my $oid = $dbh->func( "/absolute/path/to/file", 'lo_import' );

Works fine for me. What version of DBD::Pg are you using? Try something
recent if you are using something old. You can also set the trace
level to see what's going on behind the scenes:

$dbh->trace(10)

Thanks for your reply.
Actually, after much trial and error I figured out the problem: the handle I
was using had AutoCommit set. I'm new to the lo_* functions, and not aware
of this issue. A mention of this in the DBD::Pg docs would be very helpful
to LO noobs like me.

Cheers,

Kynn

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Actually, after much trial and error I figured out the problem: the handle I
was using had AutoCommit set. I'm new to the lo_* functions, and not aware
of this issue. A mention of this in the DBD::Pg docs would be very helpful
to LO noobs like me.

Ah, that clears things up. Definitely a multi-part bug on our part. I've updated
the DBD::Pg docs to mention that the large object functions will not work if
AutoCommit is enabled. The dbdpg code now throws an error if the functions are
called while in the AutoCommit state. However, I also carved out exceptions for
lo_import and lo_export: they are atomic, so no reason why they should not work
even with AutoCommit! All of this will be in the next release of DBD::Pg,
version 2.11.9, which should be released in the next few days. I also opened a
bug for this, which is now the best place to track the issue:

https://rt.cpan.org/Ticket/Display.html?id=44461

Thanks for reporting this and for following up once discovering the AutoCommit part.

- --
Greg Sabino Mullane greg@turnstep.com
End Point Corporation
PGP Key: 0x14964AC8 200903220006
http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8
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