InterBase MEMO/BLOB fields, data with size > 1MB

From: pet (pet.17464k_at_mail.codecomments.com)
Date: 05/31/04 

Date: Mon, 31 May 2004 04:18:15 -0500

I appreciate any help. In my Perl script I have a code part that fetches
a data from database InterBase, everything works fine except in case
when fetched data has size of over 1MB! Script(s) work just fine if the
"content" in MEMO or BLOB fields of the database has smaller size than
1MBytes; if size of the file (data) is over 1MB then "ERROR: Blob
exceeds maximum length" is generated in the "error.log" of the Apache
Server (and of course data is not fetched):

# . . . . . - rest of the code
        use DBI;
# . . . . . - rest of the code
                # name & location of the database
        $dbpath = 'C:\Database\database_01.fdb';
        $dsn =
"DBI:InterBase:database=$dbpath;host=123.456.78.9;ib_dialect=3";
                # connesting to DB
        $dbh = DBI->connect($dsn, '', '', {AutoCommit => 0}) or die
"$DBI::errstr";
                # setting the size of the buffer (1KB)
        $dbh -> {LongReadLen} = 1024;
                # NO matter if Truncation is ON or OFF? Tried both cases!
        #$dbh -> {LongTrun***} = 0;
        $dbh -> {LongTrun***} = 1;

                # here, DATA is MEMO field in the database!
        $sql = "SELECT FIRST 1 DATA FROM CONFIGURATION ORDER BY CREATEDDATE
DESC";
        $sth = $dbh->prepare($sql) or die "Preparing: ", $dbh->errstr;
        $sth->execute or die "Executing: ", $sth->errstr;
                # opening FILE HANDLER for writing the content of the MEMO/BLOB
field
        open (F, ">./database1.txt");
                # fetching the content
        while (@row = $sth->fetchrow_array()) {
                foreach (@row) {
                # saving into the file "database1.txt"!
                        print F "$_";
                }
        }
        close F;
        $sth->finish;
        $dbh->commit or warn $dbh->errstr;
        $dbh->disconnect or warn $dbh->errstr;
# . . . . . - rest of the code

I have tried several workarounds (in the current code I've increased
the size of the buffer, LongReadLen - EVEN to 10MB; also tried with
chunks & blob_read method - to get small pieces of data & to
compose/concatenate them again at the end BUT got nothing, even with
data that had size of only 10KB!), everytime it was unsuccessfully!
Maybe I should replace the DBD-InterBase with some other Perl module?
Installed Environment: Perl version 5.6.1, Firebird 1.5.0 (database:
InterBase) and I have two similar scripts (Win32 & Unix), both work OK
when fetched data had smaller size than 1MB, installed Perl modules:
DBI 1.37, DBD-InterBase 0.40.

*NOTICE: I read this:
"The DBI currently defines no way to insert or update LONG/LOB values
piece-wise - piece by piece. That means you're limited to handling
values that will fit into your available memory."
as well as:
"Read/Write BLOB fields block by block not (yet) supported. The
maximum size of a BLOB read/write is hardcoded to about 1MB."
- Does that mean that I can't get data using DBI and DBD:InterBase
with size larger than 1MB?

Please help me with any ideas, hints or solutions! Thanks. 

--
pet
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