RE: odbc_lob_read chunk is short

"odbc_lob_read(sth, colno, buf, length, \%attrs)
where \%attrs can contain TYPE => SQL_type."
http://www.nntp.perl.org/group/perl.dbi.dev/2010/07/msg6140.html


where Type should be SQLBINARY

http://www.nntp.perl.org/group/perl.dbi.dev/2010/09/msg6258.html


"It turns out I was mistaken as DBD::Oracle DOES implement blob read
although I've not tested it works. Someone, in the distant past
attempted an implementation in DBD::ODBC but it does NOT work and is
seriously flawed."
http://www.nntp.perl.org/group/perl.dbi.dev/2010/07/msg6144.html

Martin 
______________________________________________ 
"Confusion and Obfuscation directives from Corporate can be disregarded for OpenSource implementations"..Latest Memo

  



> Date: Fri, 6 Sep 2013 09:18:57 +0100
> From: [email protected]
> To: [email protected]
> Subject: Re: odbc_lob_read chunk is short
> 
> On 05/09/13 20:28, Mike Grau wrote:
> > Hello,
> >
> > I am completely new at this, but I am trying to read a BLOB in chunks
> > via ODBC in Oracle 11g using DBD::ODBC-1.43, unixODBC-2.3.1 and
> > oracle-instantclient11.2-odbc-11.2. I can read an entire BLOB in one
> > read and write it to the filesystem, but I really need to be able to do
> > it in chunks, I think.
> >
> > Reading the BLOB in chunks, but I am always getting one byte less than
> > requested, losing the last byte, which results in a corrupt document (a
> > PDF) when written to the filesystem. I'm at a loss as to why this is
> > happening and how to correct it.
> >
> > Using this snippet based on the example provided by DBD::ODBC...
> >
> > while($len = $s->odbc_lob_read(1, \my $x, 8, {TYPE => 999})) {
> > print "len=$len, x=$x\n";
> > }
> >
> > ... produces this output:
> >
> > len=7, x=435886
> > len=7, x=0000 n
> > len=7, x=0001282
> > len=7, x=60 0000
> >
> > And a tracefile shows the same.
> >
> > SQLGetData(col=1,type=-2)=1 (retlen=2046252)
> > <- odbc_lob_read= ( 7 ) [1 items] at /root/lob_read.pl line 45
> > >> odbc_lob_read DISPATCH (DBI::st=HASH(0x203c940) rc1/1 @5 g2 ima0
> > pid#11494) at /root/lob_read.pl line 45
> > -> odbc_lob_read for DBD::ODBC::st (DBI::st=HASH(0x203c940)~0x203c9d0 1
> > SCALAR(0x1e0a440) 8 HASH(0x203c970)) thr#1cea010
> > SQLGetData(col=1,type=-2)=1 (retlen=2046244)
> > <- odbc_lob_read= ( 7 ) [1 items] at /root/lob_read.pl line 45
> > >> odbc_lob_read DISPATCH (DBI::st=HASH(0x203c940) rc1/1 @5 g2 ima0
> > pid#11494) at /root/lob_read.pl line 45
> > -> odbc_lob_read for DBD::ODBC::st (DBI::st=HASH(0x203c940)~0x203c9d0 1
> > SCALAR(0x1e0a440) 8 HASH(0x203c9a0)) thr#1cea010
> >
> > Can someone please give me some guidance how to get the full chunk
> > requested?
> >
> > I'm using
> > unixODBC-2.3.1 - built from the tarball
> > DBD-ODBC-1.43 - installed from the tarball (perl Makefile.PL; make;
> > make install)
> > oracle-instantclient11.2-odbc-11.2.0.3 installed from RPM
> > DBI is the distro's perl-DBI-1.617-4.1.1.x86_64 (openSUSE 12.3)
> > The database and client are both x86_64
> >
> > The instant client is link against libodbcinst.so.1 and unixODBC now
> > provides libodbcinst.so.2, so I symlinked them:
> > libodbcinst.so.1 -> /usr/local/lib64/libodbcinst.so.2
> > Ugly, but seems to work.
> >
> > Ultimately I want to index documents stored in Oracle with Sphinx and so
> > must use ODBC. I'd like to know that this much is working before moving
> > on to Sphinx.
> >
> > TIA -- Mike G.
> >
> 
> Bear with me and I'll take another look at that code. If I cannot see anything I might need to send you a new version with slightly different logging. By all means nag me if I don't get back to you by tomorrow.
> 
> Martin
> -- 
> Martin J. Evans
> Easysoft Limited
> http://www.easysoft.com