[SOLR-10448] [LTR] Feature vector caching separation

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Alessandro Benedetti
• Created: 07/Apr/17 15:16
• Updated: 08/Jun/19 15:22

Description

We have different type of features, and their nature is different :
SolrFeature -> can be query dependent / query independent
FieldValueFeature -> query independent
Value Feature -> query level
OriginalScoreFeature - > query dependent

Intuition
Let's see when the extracted value for a feature change :

Query independent ( document level features) -> indexing time, every commit may change the feature value and possibly invaldiate the cache entry

query dependent -> both request parameters and index can change the feature value

query level -> only request parameters can change the value, it is not affected by the index

Caching
let's see the benefits of having 3 separate caches ( so the feature vector components will be separated) :

Query independent feature Cache -> simply changing the request parameters will not invalidate the cache entry, only a commit will cause the autowarming

Query Dependent Feature Cache -> this will behave like the current cache, so changing params you will cache a different feature vector

Query level Cache ->the index is not involved at all

I have not yet investigated how caching internally works in the LTR plugin so i don't know how much effort would imply.