fix: apply score threshold after reranking in hybrid search#35263
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fatelei merged 2 commits intoApr 16, 2026
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The score threshold was applied to pre-rerank/fusion scores before the reranker ran. Documents with high reranked scores (0.84-0.96) were incorrectly filtered out because their pre-rerank scores were below the threshold. Move score threshold filtering to after the reranking step so it uses the final scores users see in the UI. Fixes langgenius#35233 Made-with: Cursor
fatelei
reviewed
Apr 16, 2026
…search Per reviewer feedback, set embedding_score_threshold to 0.0 rather than None when deferring threshold to post-rerank filtering. Made-with: Cursor
Contributor
Pyrefly DiffNo changes detected. |
fatelei
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Apr 16, 2026
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Hi, I am using Dify Cloud and tested this after the PR was merged but the behavior appears unchanged — score threshold is still being applied before reranking in hybrid search. Could you confirm whether this fix has been deployed to Dify Cloud, or if I need to wait for a specific release? Thanks. |
Contributor
yes, in next release |
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Summary
Fixes #35233
In hybrid search with reranking enabled, the score threshold is applied to the pre-rerank/fusion score instead of the post-rerank score. This causes documents with high reranked scores (0.84-0.96) to be filtered out because their pre-rerank scores were below the threshold.
Root Cause
RetrievalService.embedding_searchpassesscore_thresholdto the vector DB query forHYBRID_SEARCH, which filters on pre-rerank similarity scores. After reranking produces new scores, the threshold-filtered results are already gone.Fix
HYBRID_SEARCH, passscore_threshold=Noneto the vector DB search step so no pre-filtering occursRerankModelRunner,WeightRerankRunner) apply the threshold to the final reranked/fused scoresMade with Cursor