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_r334744437
##########
File path: lucene/core/src/java/org/apache/lucene/search/LRUQueryCache.java
##########
@@ -732,8 +737,38 @@ 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 > leadCost * skipCacheFactor) {
Review comment:
Yes, the multiplication may overflow. Considering _leadCost_ may be zero, I
will use `cost / skipCacheFactor > leadCost` to replace the multiplication.
BTW, I found out that why my tests success is that _leadCost_ was always 1.
I will strengthen my tests a little.
----------------------------------------------------------------
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
