I have the question with regard to Alfresci CE 4.0d
Is it possible and whe it is the case, how it is possible to perform Lucene AND Solr indexing at the same time? And perform Lucene OR Solr Search by choose once per startup of Alfresco Server?
Solr and Lucene indexing can be done in parallel when you set your search subsystem to "Lucene" and have SOLR running in parallel. But I guess what you actually want is "searching" Lucene and SOLR in parallel. This, I'm afraid is not possible - or at least not easily done, as you'd have to modify code from Alfresco's core.