On 7/24/2014 8:45 PM, YouPeng Yang wrote: > To Matt > > Thank you,your opinion is very valuable ,So I have checked the source > codes about how the cache warming up. It seems to just put items of the > old caches into the new caches. > I will pull Mark Miller into this discussion.He is the one of the > developer of the Solr whom I had contacted with. > > To Mark Miller > > Would you please check out what we are discussing in the last two > posts.I need your help.
Matt is completely right. Any commit can drastically change the Lucene document id numbers. It would be too expensive to determine which numbers haven't changed. That means Solr must throw away all cache information on commit. Two of Solr's caches support autowarming. Those caches use queries as keys and results as values. Autowarming works by re-executing the top N queries (keys) in the old cache to obtain fresh Lucene document id numbers (values). The cache code does take *keys* from the old cache for the new cache, but not *values*. I'm very sure about this, as I wrote the current (and not terribly good) LFUCache. Thanks, Shawn
