Use of bind variables in sql statements can also be a big help, as sql statements can then be parsed (in Oracle) only once. See the DBD::Oracle doc for use of bind variables; some of my example code is below. Example code is for loading binary objects into a DB, but does use bind variables. Also, there's probably a more efficient way to write this, but it worked for me.

# load modules

use DBI;
use DBD::Oracle qw(:ora_types);

# connect to the db

my $dbh = DBI->connect("dbi:Oracle:tlin","USERNAME","PASS") 
    or die "Cant connect to db! $DBI::errstr\n";

$LONG_RAW_TYPE=ORA_LONGRAW; # oracle type id for long raw/blob ( could
+ also be 24)

$bufsize = 400000; # putting this here, since we use it everywhere

$dbh->{LongReadLen}=$bufsize; # dont set this too high; performance su
+ffers
$dbh->{LongTruncOk}=0;


# find all the .xls in a dir and load them to db

while ( defined(my $filename = glob("c:\\play\\tmp\\*"))){
    open (BLOB, "<$filename") or die "Cant open $filename\: $!\n";
    binmode(BLOB);
    my $bytes = 0;
    my $buf;
    $bytes = read(BLOB, $buf, $bufsize);
    if ( $bytes > $bufsize ){
        print STDERR "File $filename too large to load.  Skipping.\n";
        close(BLOB);
        next;
    }
    close(BLOB);

    # fix the file name; one undef for each part of the path which is 
+not a file name.
    my ( undef, undef, undef, $storname ) = split /\\/, $filename;
    
    my $sth=$dbh->prepare("
        insert into blobtest \( id\, fname\, fobj \)
        values \( 
        blobid\.nextval\, \'$storname\'\, \:blob
        \)
        ") or die "Cant prep\: $DBI::errstr\n";
    $sth->bind_param(":blob", $buf, {ora_type=>$LONG_RAW_TYPE});
    $sth->execute or die "Cant exec\: $DBI::errstr\n";
    print "File\: $filename loaded\n";
};
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More generally, take a look at overall Oracle parameters / tuning. Usually the defaults on DB creatation are insanely low and need adjusted much higher, but not so high that swapping / paging ensues.