Meta collections: relative weighting
Introduction
It is possible to apply collection-level weightings to components in a meta collection to allow up-weighting/down-weighting of results based on the collection that they are sourced from. This approach is similar to that used by query independent evidence but with the following benefits:
- No dependency on URL structures
- Weighting is applied at query-time (no reindexing required)
This is achieved by directly editing $SEARCH_HOME/data/META-COLLECTION/live/idx/index.sdinfo, which uses the following structure:
$SEARCH_HOME/data/COLLECTION/live/idx/index ALIAS WEIGHT
Where:
- COLLECTION is the component collection identifier
- ALIAS is the the reference used by the
cliveparameter (typically the same as COLLECTION) - WEIGHT is a value between 0 and 1.0 (defaults to 0.5)
How to apply the weightings
Assign weightings to each component in the meta collection
After creating a meta collection (store) containing products and faqs component collections, edit $SEARCH_HOME/data/store/live/idx/index.sdinfo:
/opt/funnelback/data/products/live/idx/index products 1.0
/opt/funnelback/data/faqs/live/idx/index faqs 0.5
This would have the effect of giving all results from the products collection the maximum possible upweighting, while leaving faqs at the default weight.
Assign the level of influence of collection level weighting
The influence that component weighting has on the ranking algorithm is controlled by adding the cool.21 ranking option to your query_processor_options or padre_opts.cfg. You can test the effect of this before applying by using the CGI cool.21 parameter. The range of the value for cool.21 is 0.0 - 1.0 with 1.0 being the maximum influence that can be applied to component weighting.
query_processor_options=-cool.21=0.75