[Mediawiki-l] Touchgraph possibility

[FxParlant]

As I managed the first step for a touchgraph specialpage (yet only for 
Category:pages), I start a new thread.

I - Refactoring in 1.5 ?

On a previous thread (don't ask me where), Rowan Collins (as far as I 
remember) wrote that in the 1.5 version, the database would be totally 
refactured. Is the map already available? Will it affect a lot the 
"links" and "categorylinks" tables?

II - Touchgraph coding

1)Touchgraph Architecture

The touchgraph engine feeds the applet with an xml file containing two 
parts:
  - All the nodes (id, label, colors, mouseover hint-html-...)
  - All the edges(links) (from_id, to_id)


REMARK:
-------
The problem is that it works if a node has no edges, but it dies if it 
exists an edge with an id of a node which doesn't exist.


2) Mysql queries

   a)To produce the list of nodes I used:

$sql = "SELECT cur_id,cur_namespace,cur_title,cur_is_redirect FROM cur 
WHERE cur_namespace=14 OR cur_namespace=0 ORDER BY `cur_id` DESC";

   b)To produce the list of edges I used:

$sql="select cfrom.cur_id AS bfrom, cto.cur_id AS bto
FROM categorylinks
INNER JOIN cur AS cfrom ON (cfrom.cur_id = categorylinks.cl_from AND 
cfrom.cur_namespace=14)
INNER JOIN cur AS cto ON (cto.cur_title = categorylinks.cl_to AND 
cto.cur_namespace=14)";

As I said to Richard Holton (cf. "need mysql geek"), a simple query 
wasn't enough because I need  to be sure that the edges are BOTH 
existing nodes in the cur table. Otherwise the engine dies.

QUESTIONS

   a)Has anybody got an idea of the queries for the normal pages d:-D) ?

   b)The file is already very heavy. For a use in production (I mean in 
a public wikipedia site), can someone think of the type of indexes which 
could be useful ?
     - I thought for example of a listing on a limited level of links: 
give the starting page, and the engine will produce a listing of nodes 
up to three nodes level away from the starting page.

   c)Can someone recode in Java the engine to get something more like 
the two frames tikiwiki extension

REFERENCES

http://www.touchgraph.com/ (touchgraph official page)
http://www.fxparlant.net/Special:Touchgraph (my demo on my mediawiki 
category pages)


François