On 03/02/2016 11:28, Vikas Saurabh wrote: > Hi Davide, > > I think 'OR' gets passed as constraints to underlying index engine > (property, lucene, solr) etc. For lucene case (I guess solr too), I > think having a bunch is of 'OR' is more useful than doing a union at > query engine as: > * single query to lucene would save multiple hops into index > * lucene's default relevance sort is very useful (as it orders more > matched 'OR's over less matches) > > So, while agree, that the result would be same at the end of day but > we 'might' get less performant. While I agree in principle if we don't go in such direction we'll have to find solutions for the addressed bug by the conversion itself. In terms of performances it performs already a cost analysis. It ask for the cost of every alternatives and pick up the cheapest.
Plus as per Oak we don't really provide any index definitions there could be cases where, for example, lucene is not there. > > Disclaimer: I'm assuming UNION implies 'solving each query > indepedently and provide union-ed result'. Ignore this mail, if that's > not the case. yes it does. Davide
