Re: sorting large numbers of large records

["Matthew Heaney" <matthewjheaney@earthlink.net>]

"Brien L. Christesen" <blchrist@rac2.wam.umd.edu> wrote in message
news:bg3fgg$qig$1@grapevine.wam.umd.edu...
>
>
> I couldn't really find much discussion of doing external sorts in Ada (or
> much literature on external sorts at all) so I'm not sure if this is a
> good approach to be taking, or if there is a better way to do the sort.  I
> tried creating an index, sorting the index, and then creating the results
> file based on the index.  Jumping around the file with direct_io led to
> awful results, though.  The execution time of the part of the code that
> read the index, got the corresponding value from the large record file,
> and wrote that record to a new file grew exponentially.
>
> Does anyone know of a good way to do this kind of sort?  Thanks in advance
> for any responses.

I forgot to mention that I also wrote both indexed i/o and indexed
sequential i/o containers.  These might be useful for minimizing how many
elements are kept in main memory.  (The indexed i/o files are implemented
using a B-tree.)

http://www.adapower.com/reuse/indexed_io.html


-Matt