[LUCENE-10418] Improve Query rewriting for non-scoring clauses

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 9.2
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Adrien Grand
• Created: 10/Feb/22 09:16
• Updated: 28/Aug/22 16:36
• Resolved: 17/Mar/22 15:52

Description

Query rewriting is occasionally important for performance, e.g. it may allow using an optimized bulk scorer instead of the default bulk scorer like in the example from LUCENE-10412.

One case when we could simplify queries is in the non-scoring case. All layers of query wrappers that only affect scoring like BoostQuery and ConstantScore query can be removed, which might help identify new opportunities for rewriting. For instance, we have several rewrite rules that optimize for MatchAllDocsQuery and would fail to recognize it if it is behind a ConstantScoreQuery or a BoostQuery. Boolean queries can also simplify themselves in the non-scoring case, by changing MUST clauses to FILTER clauses, or removing fully optional SHOULD clauses.

Issue Links

• links to: GitHub Pull Request #672