Issue
Users attempting to demote or "bury" specific documents in search results using a low boost value (e.g., 0.8) may find that the documents still appear at the top of the result set. This occurs because any positive boost value continues to contribute to the document's total relevancy score, which may still be higher than other documents even after the multiplier is applied.
Diagnosis
When analyzing the debugQuery=true output, it becomes evident how Solr calculates the final score. In cases where a document has a strong base score or significant signal boosting, applying a low positive boost (less than 1 but greater than 0) does not sufficiently reduce the score to move the document down.
For example, a Lucene query syntax rule such as:
query({!lucene q.op=OR v='field_name:"Value"^=0.8'},1)Still results in a positive score contribution. If the base score of the document is high, a 20% reduction (0.8 boost) is often insufficient to overcome the scores of other relevant documents.
Environment
Fusion Version: 5.9.14
Product Line: Fusion (Self-Hosted/Managed)
Platform: Kubernetes (EKS)
Components: Query Rewrite Service, Solr, Predictive Merchandiser
Cause
In Solr-based scoring, a boost value between 0 and 1 reduces the score but keeps it positive. If the document matches other high-weight criteria (such as specific ID boosts or signals), the aggregate score remains high enough to keep the document in a prominent position. Effective "burying" requires the score to be negligible or negative compared to the rest of the result set.
Resolution
To effectively demote results, use one of the following three methods:
Use a Negligible Boost Value
Instead of a value like 0.8, use a significantly smaller decimal to ensure the score contribution becomes negligible.
Example: Update the boost to
0.0001.
Apply a Negative Boost
A negative boost can be applied to the query to actively penalize the document score.
Example Syntax:
field_name:"Value"^-100Implement a Bury Rule Action
The most robust method within Fusion is to use the native "Bury" action in Predictive Merchandiser rather than a "Boost" action with a low value.
The Query Rewrite stage handles Bury rules by moving identified documents to the end of the result set.
This is often achieved by Fusion applying a very large negative boost or utilizing a specific sort order override.
To implement this, navigate to the Predictive Merchandiser UI, select the desired products or query matches, and select the Bury action from the rule configuration menu.
Verification
To verify the change, append the following parameter to your query request to inspect the score calculation:
curl -u <user>:<pass> "http://proxy:8764/api/queries/<collection>?q=your_query&debugQuery=true"In the output, search for the weight and product of sections for the specific Document ID to confirm that the demotion logic is reducing the score as expected.