> As I learned, big data, such as Lucene index, was not > suitable to be > updated frequently.
Some people use ExternalFileField for PageRank-like fields. http://lucidworks.lucidimagination.com/display/solr/Solr+Field+Types#SolrFieldTypes-WorkingwithExternalFiles Lucene supports parent/child documents, may be that can be used too. http://blog.mikemccandless.com/2012/01/tochildblockjoinquery-in-lucene.html
