From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id LAA25816; Thu, 2 Jan 2003 11:03:28 +0100 (MET) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id LAA25565 for ; Thu, 2 Jan 2003 11:03:27 +0100 (MET) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id h02A3QH10841 for ; Thu, 2 Jan 2003 11:03:26 +0100 (MET) Received: (from xleroy@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id LAA25102 for caml-list@inria.fr; Thu, 2 Jan 2003 11:03:26 +0100 (MET) Date: Thu, 2 Jan 2003 11:03:26 +0100 From: Xavier Leroy To: caml-list@inria.fr Subject: Re: [Caml-list] Cross-platform DBM equivalent? Message-ID: <20030102110326.J24166@pauillac.inria.fr> References: <20021226071747.GC1071@swordfish> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <20021226071747.GC1071@swordfish>; from mgushee@havenrock.com on Thu, Dec 26, 2002 at 12:17:47AM -0700 Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk > I am developing an application that needs fast access to persistent > configuration data, and I thought that DBM might be a good way to > provide that functionality ... but I see that DBM isn't available on > Windows. As others mentioned, you could compile the C sources for a DBM implementation on Windows, then build the Caml/DBM binding. > Is there something similar that works on all platforms? Or an > alternative approach? > By the way, I'm at an early prototyping stage, so I can't be much more > specific about my needs. What I can say at this point is that speed is > important; I think I need a key-value data structure, and it's probably > okay for the types of both keys and values to be limited to strings, as > with DBM. I guess it all depends on the number of key-value pairs: - For a few hundred entries, just parsing a plain text file is very fast, e.g. using an ocamllex-generated lexer to do the parsing. Plain text files also make debugging easier. - Up to 10^5 entries, input_value of a hash table or a "map" is quite fast, e.g. less than 0.1 seconds. This is what I use in the SpamOracle mail filter to read the database of word frequencies. It is true that the binary format used by input_value may change in future OCaml releases, but so does the format of DBM databases, and the input_value format hasn't changed in incompatible ways since 1996 or so :-) Still, it is prudent to support conversions between input_value form and some textual, portable form. - Beyond 10^5 entries, either DBM or a real database (such as MySQL) seems best. Remember that DBM files are quite large, so an SQL approach might be more effective. Hope this helps, - Xavier Leroy ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners