Hello, queryResultWindowSize sets the number of documents to cache for each query in the queryResult cache. So if you normally output 10 results per pages, and users don't go beyond page 3 of results, you could set queryResultWindowSize to 30 and the second and third page requests will read from cache, not from disk. This is well documented in both the Solr example solrconfig.xml file and the Solr documentation.
However, the example in solrconfig.xml and the documentation in the reference manual for Solr 4.10 say that queryResultMaxDocsCached : "sets the maximum number of documents to cache for any entry in the queryResultCache". If this were true, then it would seem that this parameter duplicates queryResultWindowSize. Looking at the code it appears that the queryResultMaxDocsCached parameter actually tells Solr not to cache any results list that has a size over queryResultMaxDocsCached:. From: SolrIndexSearcher.getDocListC // lastly, put the superset in the cache if the size is less than or equal // to queryResultMaxDocsCached if (key != null && superset.size() <= queryResultMaxDocsCached && !qr.isPartialResults()) { queryResultCache.put(key, superset); } Deciding whether or not to cache a DocList if its size is over N (where N = queryResultMaxDocsCached) is very different than caching only N items from the DocList which is what the current documentation (and the variable name) implies. Looking at the JIRA issue https://issues.apache.org/jira/browse/SOLR-291 the original intent was to control memory use and the variable name originally suggested was "noCacheIfLarger" Can someone please let me know if it is true that the queryResultMaxDocsCached parameter actually tells Solr not to cache any results list that contains over the queryResultMaxDocsCached? If so, I will add a comment to the Cwiki doc and open a JIRA and submit a patch to the example file. Tom . --------------------------- http://svn.apache.org/viewvc/lucene/dev/branches/lucene_solr_4_10/solr/example/solr/collection1/conf/solrconfig.xml?revision=1624269&view=markup 635 <!-- Maximum number of documents to cache for any entry in the 636 queryResultCache. 637 --> 638 <queryResultMaxDocsCached>200</queryResultMaxDocsCached>