[ZODB-Dev] Indexing: Query Optimization

[Christian Robottom Reis]

On Tue, May 03, 2005 at 02:44:58PM +0200, Thomas Guettler wrote:
> It would be better if the index would do the search for customer_id
> first, and then filter the result by deleting entries which are not in
> the given time period.
> 
> Has anyone done such a "Query Optimization"? (Zope, Zope3, IndexCatalog, ...)

I have done it, but the way we do it in IC is synthesize an index
on-the-fly and then do the range query through it. The code is in
Indexes.py:build_temp_index; it's a nasty little hack.

> Since btrees and btree ranges don't know their size, you need to do something 
> like this:
> - do range searches at the end
> - if index "foo" is used, use it first, ...

Hmmm. Can you elaborate on this? I don't quite grasp what you mean.

I think the only way to implement this correctly is using a different
data structure -- one that allows you to slice and dice your data in
different axis. I may be short-sighted, though.

Take care,
--
Christian Robottom Reis | http://async.com.br/~kiko/ | [+55 16] 3361 2331