jgq2008303393 commented on a change in pull request #940: LUCENE-9002: Query caching leads to absurdly slow queries URL: https://github.com/apache/lucene-solr/pull/940#discussion_r334223157
########## File path: lucene/core/src/java/org/apache/lucene/search/LRUQueryCache.java ########## @@ -732,8 +741,39 @@ public ScorerSupplier scorerSupplier(LeafReaderContext context) throws IOExcepti if (docIdSet == null) { if (policy.shouldCache(in.getQuery())) { - docIdSet = cache(context); - putIfAbsent(in.getQuery(), docIdSet, cacheHelper); + final ScorerSupplier supplier = in.scorerSupplier(context); + if (supplier == null) { + putIfAbsent(in.getQuery(), DocIdSet.EMPTY, cacheHelper); + return null; + } + + final long cost = supplier.cost(); + return new ScorerSupplier() { + @Override + public Scorer get(long leadCost) throws IOException { + // skip cache operation which would slow query down too much + if ((cost > skipCacheCost || cost > leadCost * skipCacheFactor) Review comment: Yes. With a 250x higher cost, it’s good enough now without _skipCacheCost_. Also we find that _skipCacheCost_ could be done through the following code. Although we think that the allowed cache entry size is a little large, we are not going to modify it now. If we find that the demand is very strong, we will open a new PR. https://github.com/apache/lucene-solr/blob/61a00822e78a02f14ac060dabf66c2b5053c12d7/lucene/core/src/java/org/apache/lucene/search/LRUQueryCache.java#L679-L691 I will submit a new patch that remove _skipCacheCost_. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org