[Catalog-sig] Flamenco queries

["Martin v. Löwis"]

> It looks like the __init__ builds a data structure and then
> get_matches() and list_choices() run off this structure.  It would
> certainly be worth fixing this!

I have now committed a fix in PyPI (r441) which performs the computation
of selected entries in SQL, considerably improving browsing if
categories are selected.

If no categories are selected, browsing is still slow. This could be
improved by caching a tally table, as the standard browse page does
not need to report any package names (just a tally).

Is there any efficient way to compute a tally in PostgreSQL on the
fly?

Regards,
Martin