Raul, I believe that Eric's JD does exactly what you suggest. dbi.ijs was written more for comphrehension and compatibility with old APL code than performance but I was pleased by how effective it was. Organizing database tables by columns just works.
Have a great new year. I'll be looking forward to seeing you in Toronto at the next J conference this summer. John On Fri, Dec 27, 2013 at 8:45 AM, Raul Miller <[email protected]> wrote: > Nice! > > That said,here are some untested ideas for alternative implementations. > > First, 1!:1 and 1!:2 are nicely modular, but if you want high > performance the apl shared variable concept (visible in J's mapped > files) can give you higher performance. For an "inverted file" (or > "table implemented as a named list of columns), it would be tempting > to implement this as: > > A top level structural file, defining the columns, and one file for > each column (all using the same name prefix, to slightly reduce the > tedium of potential manual recovery work). > > You lose slightly with the overhead of opening those files, but if > speed matters and you have a lot of data you gain from not having to > read whichever columns are currently irrelevant. > > That said, there are a variety of other optimization techniques you > can apply to this kind of system when you run into performance issues. > > Thanks, > > -- > Raul > > On Thu, Dec 26, 2013 at 11:15 PM, John Baker <[email protected]> wrote: > > I've put up some more goodies in jacks. dbi.ijs is a simple inverted file > > system that can be shared with companion APL and C# systems. > > > > > http://bakerjd99.wordpress.com/2013/12/26/apl-software-archaeology-dbi-edition/ > > > > Check out the APL character Christmas tree - latex generated. > > > > > > On Mon, Dec 23, 2013 at 1:29 PM, John Baker <[email protected]> wrote: > > > >> Jurkey - a cross of J and turkey yielding something like jerky. I like > it. > >> Cheers > >> > >> > >> On Mon, Dec 23, 2013 at 8:56 AM, Y-01 <[email protected]> wrote: > >> > >>> John, thanks for your J-turkey for Christmas. > >>> > >>> > >>> On Sat, Dec 21, 2013 at 11:54 PM, John Baker <[email protected]> > wrote: > >>> > >>> > I have set up a GitHub repo that consolidates all the J code > referenced > >>> on > >>> > ADND. For more check: > >>> > > >>> > http://bakerjd99.wordpress.com/2013/12/21/jacks-repository/ > >>> > > >>> > Merry Christmas worldwide J'ugglers. You guys/gals consistently > produce > >>> the > >>> > most interesting email in my inboxes. > >>> > > >>> > -- > >>> > John D. Baker > >>> > [email protected] > >>> > > ---------------------------------------------------------------------- > >>> > For information about J forums see > http://www.jsoftware.com/forums.htm > >>> > > >>> ---------------------------------------------------------------------- > >>> For information about J forums see http://www.jsoftware.com/forums.htm > >>> > >> > >> > >> > >> -- > >> John D. Baker > >> [email protected] > >> > > > > > > > > -- > > John D. Baker > > [email protected] > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- John D. Baker [email protected] ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
