[ZODB-Dev] Indexing: Query Optimization

[Thomas Guettler]

Hi,

I developed a simple index using ZODB. Searching for single values is
very fast. Searching big ranges is slow.

Example: 
Search: 

customer_id=0815
date_start=2001-01-01
date_end=2004-12-31

The index holds a btree which maps values to docids. The search
for customer_id is very fast (Maybe 500 results) . But the range search from 
date_start to date_end is slow (Maybe 100.000 results).

Up to now I use the intersection method of the BTree package to
join the result with a logical AND.

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, ...)

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, ...

 Thomas