Suggestion about LRUQueryCache Optimization

[boicehuang]

Description

https://github.com/apache/lucene/blob/main/lucene/core/src/java/org/apache/lucene/search/LRUQueryCache.java#L747

Can we use ReentrantReadWriteLock in LRUQueryCache (Currently ReentrantLock) to allow reading cache concurrently, to improve search performance？

I benchmarked this optimization by mocking some random LongPoint and querying them with PointInSetQuery with bool filter.

doc count	field cardinality	query point	baseline QPS	candidate QPS	diff percentage
30000000	10	1	2481	5102	105.6%
30000000	1000000	1	6396	6596.48	3.1%

I think this change can help filter queries that need to query low-cardinality fields. If it helps, I will submit a PR.

[boicehuang]

@jpountz what you think on this? Any help will be appreciated.

[boicehuang]

#13306

[jpountz]

Fixed by #13306.