Message 90

Answers

X-Added: With Flames (bblib $Revision: 1.4 $)
Return-path: <spapadim+@cs.cmu.edu>
X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail
Received: from po0.andrew.cmu.edu via trymail for bb+academic.cs.15-721@andrew.cmu.edu
          ID </afs/andrew.cmu.edu/usr0/bb/Mailbox/YvokSqS00UdYF2GU4X>;
          Sun, 21 Oct 2001 13:36:54 -0400 (EDT)
Received: from mx2.andrew.cmu.edu (MX2.ANDREW.CMU.EDU [128.2.10.112])
        by po0.andrew.cmu.edu (8.9.3/8.9.3) with ESMTP id NAA16961
        for <bb+academic.cs.15-721@ams.andrew.cmu.edu>; Sun, 21 Oct 2001 13:36:53 -0400 (EDT)
Received: from iluvatar.dhs.org (pool-151-201-19-40.pitt.east.verizon.net [151.201.19.40])
        by mx2.andrew.cmu.edu (8.12.0.Beta16/8.12.0.Beta16) with ESMTP id f9LHaqtx007317
        for <bb+academic.cs.15-721@andrew.cmu.edu>; Sun, 21 Oct 2001 13:36:52 -0400
Received: from cs.cmu.edu (iluvatar.hobbiton.cmu.edu [192.168.0.2])
        by iluvatar.dhs.org (Postfix) with ESMTP
        id B2A0F20515; Sun, 21 Oct 2001 13:36:52 -0400 (EDT)
Message-ID: <3BD307B3.1010908@cs.cmu.edu>
Date: Sun, 21 Oct 2001 13:36:51 -0400
From: Spiros Papadimitriou <spapadim+@cs.cmu.edu>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.3) Gecko/20010808
X-Accept-Language: en-us
MIME-Version: 1.0
To: bb+academic.cs.15-721@andrew.cmu.edu
Cc: Francisco Pereira <fpereira+@cs.cmu.edu>, Yan Karklin <yan+@cs.cmu.edu>
Subject: Answers
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

1. Output tuples are just a concatenation of the input tuple byte strings.
   Ie. sth like
      memcpy(outrec, recR, sizeR); memcpy(outrec+sizeR, recS, sizeS);
   will do.

2. The parameter amt_of_mem is simply passed to Sort and in_type should
   always correspond to a B-tree (otherwise you can return an error).

3. The problem with
      BTreeFile *btfileS = new BTreeFile(s, filename2, in2[join_col_in2],
                                         t2_str_sizes[join_col_in2]);
   is probably that you're passing an existing filename, which does *not*  
   correspond to a B-tree file.  The second argument should be the filename
   of the B-tree file.

4. About deleting the heapfiles...  If you are not doing this, please try
   deleting the scans on the heapfiles *before* deleting the heapfiles and
   let me know if anything happens (although I assume you might be getting
   other errors if you weren't doing this already, but...).

Spiros