Hi all,
       I am reading Lucene source code recently and we also use the Elastic
Search as our search engine. As far as I know, the elastic search
performance is pretty good. The elastic search is based on Lucene. So I am
wondering that how it can search words so fast when the field data
(uninverted index) are stored in disk.
    The DocValues make access filed values fast. From my perspective, it's
of course fast when few values of a field are read. But when few fields
need to access, I think it's not fast again. Because when access a field,
all of its doc values need to read with MMap. So the system needs to read
disk to load the data.
    So could anyone help me understand the DocValues operating mechanism?

Echo Yao

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