FreeTDS Development Group

[Chris Wesley <cwwesley AT udlug.org>]

I'm using perl (5.6) with DBI (1.28), DBD::Sybase (0.93) and freetds
(0.53) to retrieve data from a M$ SQL2000 server.

Executing queries and retrieving non-text and non-image columns works
beautifully.  But I'm trying to fetch an image column too, and I've
finally run across a snag for which I haven't found a solution.  Every
time I invoke the ct_get_data() function to get the contents of an image
column, I always get some ridiculous string that is at least 136391000
bytes long (by using some dbi/dbd settings, the bytecount may change by a
a few dozen bytes).  Using sqsh (2.1), I can get the column just fine.
It doesn't matter what the actual length of the content of the column is
... I always get the same result (which is an improvement over the
segfaults I finally resolved).

Perl Script ensuing:

#!/usr/bin/perl -w
use strict;
use DBI;
my $M_HOST   = "myHost";
my $M_DB     = "myDB";
my $M_USER   = "myUser";
my $M_PASSWD = "myPasswd";
my $M_DSN    =  "dbi:Sybase:database=${M_DB};server=${M_HOST}";
my $MAX_BLOB_SIZE = 1024 * 512;
my $dbh = DBI->connect( $M_DSN, $M_USER, $M_PASSWD ) or die ("Connect 
Failed.");
   $dbh->{LongReadLen} = $MAX_BLOB_SIZE;
   $dbh->do( "set textsize ${MAX_BLOB_SIZE}" );
#################################################
my( $sth, $row, $fileName, $fetchedLength, $fileBlob );
$fileBlob = '';
$sth = $dbh->prepare("select FileName, FileBlob from Doc where DocID=8");
$sth->execute;
while( $row = $sth->fetchrow_arrayref ){
   print( "HOLD ON\n" );
   $fetchedLength = $sth->func( 2, \$fileBlob, 0, 'ct_get_data' );
   print( "Fetched Length: ${fetchedLength}\n" );
   print( "HELD ON\n" );
}
$sth->finish();
$dbh->disconnect();
# END OF SCRIPT

 -- The output is ALWAYS --
HOLD ON
Fetched Length: 136391200
HELD ON
 --
In this case, the binary stored is 33 bytes.  (I get a 66 byte hex string
from sqsh, which is correct, and properly packs back into the original
file.)

Does anyone here know what might cause this behavior?  Or know of a
different/better way to do what I'm doing?

I also have freetds sending debug info to a log file.  I don't see
anything of note there, but if anyone thinks it'd be more helpful to see,
let me know.  If I haven't adequately described the problem, feel free to
call me out on it, and I'll try to describe it better.

        TIA for any suggestions,
        ~Chris